[runtime-async] Fix timestamp instrumentation - #127662

Merged
rcj1 merged 6 commits into
dotnet:mainfrom
rcj1:fix-timestamps
May 12, 2026
Merged

[runtime-async] Fix timestamp instrumentation#127662
rcj1 merged 6 commits into
dotnet:mainfrom
rcj1:fix-timestamps

Conversation

@rcj1

@rcj1rcj1 commented May 1, 2026•
edited
Loading

Copy link
Copy Markdown
Contributor

  1. We need to ensure that new continuations are timestamped at suspension time. In an app with an async chain starting with, say, Main, curContinuation and newContinuation will both belong to Main upon resuming Main in DispatchContinuations. The async chain in t_runtimeAsyncAwaitState.SentinelContinuation!.Next has been built by the JIT via AsyncSuspend and contains newly allocated continuations for the methods above Main in the stack. These should receive a new timestamp, not that of Main.

  2. I don't think we need to add timestamps in QueueContinuationFollowUpActionIfNecessary; they have already been added in HandleSuspended.

Fixes the issue of all the timestamps being the same.
Benchmark #123727 (comment):
New: 387.4 ms
Old: 404.2 ms

@rcj1rcj1 changed the title Fix timestamp instrumentation[runtime-async] Fix timestamp instrumentationMay 1, 2026
@dotnet-policy-service

dotnet-policy-serviceBot commented May 1, 2026

Copy link
Copy Markdown
Contributor

Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag
See info in area-owners.md if you want to be subscribed.

CopilotAI reviewed May 1, 2026
View reviewed changes

CopilotAI left a comment

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview

This PR adjusts the runtime-async async-debugger instrumentation so that newly-created continuation chains get fresh timestamps at suspension time (instead of inheriting the timestamp of the currently-running continuation), and removes now-unneeded timestamp propagation logic tied to follow-up scheduling.

Changes:

  • Removed the Task.TryAddRuntimeAsyncContinuationChainTimestamps(Continuation chain, Continuation timestampSource) overload to avoid propagating an “old” timestamp to newly allocated continuation nodes.
  • Simplified AsyncDebugger.HandleSuspended / InstrumentedHandleSuspended to always timestamp based on the suspended chain head (sentinel’s Next) without a separate timestamp source.
  • Removed the SuspendRuntimeAsyncContext(ref AsyncDispatcherInfo, ...) / SuspendAsyncContext(ref AsyncDispatcherInfo, ...) path that previously timestamped the remaining chain when a follow-up continuation was queued.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

FileDescription
src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.csRemoves the timestamp-source-based chain timestamping helper, leaving chain timestamping to use a fresh suspension-time timestamp.
src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.csUpdates runtime-async instrumentation to timestamp suspended chains without using a “source continuation”, and removes the follow-up-action timestamping/suspend helper calls.

Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
CopilotAI review requested due to automatic review settings May 1, 2026 20:59
CopilotAI reviewed May 1, 2026
View reviewed changes

CopilotAI left a comment

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
@lateralusX

lateralusX commented May 4, 2026

Copy link
Copy Markdown
Member

You will need to rebase and test this on top of #127238.

@lateralusX

lateralusX commented May 4, 2026

Copy link
Copy Markdown
Member

We should probably also add some test to see if we could guard this specific scenario as well.

CopilotAI review requested due to automatic review settings May 5, 2026 19:20
CopilotAI reviewed May 5, 2026
View reviewed changes

CopilotAI left a comment

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

Comment thread...time/tests/System.Threading.Tasks.Tests/System.Runtime.CompilerServices/RuntimeAsyncTests.cs
lateralusX
lateralusX approved these changes May 12, 2026
View reviewed changes

@lateralusXlateralusX left a comment

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM!

@rcj1

rcj1 commented May 12, 2026

Copy link
Copy Markdown
ContributorAuthor

/ba-g timeouts

@rcj1
rcj1 merged commit 408f6a0 into dotnet:mainMay 12, 2026
150 of 153 checks passed
@rcj1
rcj1 deleted the fix-timestamps branch May 12, 2026 17:14
@dotnet-maestrodotnet-maestroBot mentioned this pull request May 12, 2026
Merged
This was referenced Jun 2, 2026
Closed
Closed
@github-actionsgithub-actionsBot locked and limited conversation to collaborators Jun 12, 2026
Sign up for freeto subscribe to this conversation on GitHub. Already have an account? Sign in.

Reviewers

Copilot code reviewCopilot
Copilot review effort
Applies to this pull request for everyone.Learn more about Copilot code review.
Copilot left review comments
@lateralusXlateralusXlateralusX approved these changes
@jakobbotschjakobbotschAwaiting requested review from jakobbotsch

Assignees

@rcj1rcj1

Labels

area-Diagnostics-coreclr

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

3 participants

@rcj1@lateralusX
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
[runtime-async] Fix timestamp instrumentation - #127662
Merged
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
May 12, 2026
Merged
[runtime-async] Fix timestamp instrumentation#127662
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
Conversation
@rcj1
@rcj1rcj1
commented
May 1, 2026•

edited

Loading

Copy link


Copy Markdown

Contributor
  1. We need to ensure that new continuations are timestamped at suspension time. In an app with an async chain starting with, say, Main, curContinuation and newContinuation will both belong to Main upon resuming Main in DispatchContinuations. The async chain in t_runtimeAsyncAwaitState.SentinelContinuation!.Next has been built by the JIT via AsyncSuspend and contains newly allocated continuations for the methods above Main in the stack. These should receive a new timestamp, not that of Main.
  2. I don't think we need to add timestamps in QueueContinuationFollowUpActionIfNecessary; they have already been added in HandleSuspended.
Fixes the issue of all the timestamps being the same.

Benchmark #123727 (comment):

New: 387.4 ms

Old: 404.2 ms
@rcj1rcj1
changed the title
Fix timestamp instrumentation[runtime-async] Fix timestamp instrumentationMay 1, 2026
@dotnet-policy-service
dotnet-policy-serviceBot
commented
May 1, 2026

Copy link


Copy Markdown

Contributor
Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag

See info in area-owners.md if you want to be subscribed.
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
This PR adjusts the runtime-async async-debugger instrumentation so that newly-created continuation chains get fresh timestamps at suspension time (instead of inheriting the timestamp of the currently-running continuation), and removes now-unneeded timestamp propagation logic tied to follow-up scheduling.
Changes:
  • Removed the Task.TryAddRuntimeAsyncContinuationChainTimestamps(Continuation chain, Continuation timestampSource) overload to avoid propagating an “old” timestamp to newly allocated continuation nodes.
  • Simplified AsyncDebugger.HandleSuspended / InstrumentedHandleSuspended to always timestamp based on the suspended chain head (sentinel’s Next) without a separate timestamp source.
  • Removed the SuspendRuntimeAsyncContext(ref AsyncDispatcherInfo, ...) / SuspendAsyncContext(ref AsyncDispatcherInfo, ...) path that previously timestamped the remaining chain when a follow-up continuation was queued.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.csRemoves the timestamp-source-based chain timestamping helper, leaving chain timestamping to use a fresh suspension-time timestamp.
src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.csUpdates runtime-async instrumentation to timestamp suspended chains without using a “source continuation”, and removes the follow-up-action timestamping/suspend helper calls.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
CopilotAI
review requested due to automatic review settings
May 1, 2026 20:59
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
You will need to rebase and test this on top of #127238.
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
We should probably also add some test to see if we could guard this specific scenario as well.
CopilotAI
review requested due to automatic review settings
May 5, 2026 19:20
CopilotAI
reviewed
May 5, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.
Comment thread...time/tests/System.Threading.Tasks.Tests/System.Runtime.CompilerServices/RuntimeAsyncTests.cs
lateralusX
lateralusX
approved these changes
May 12, 2026
View reviewed changes
@lateralusXlateralusX
left a comment


Copy link


Copy Markdown

Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM!
@rcj1
rcj1
commented
May 12, 2026

Copy link


Copy Markdown

ContributorAuthor
/ba-g timeouts
@rcj1
rcj1
merged commit 408f6a0
into
dotnet:mainMay 12, 2026

150 of 153 checks passed

@rcj1
rcj1
deleted the

fix-timestamps

branch
May 12, 2026 17:14
@dotnet-maestrodotnet-maestroBot
mentioned this pull request
May 12, 2026
 Merged


This was referenced Jun 2, 2026
 Closed

 Closed

@github-actionsgithub-actionsBot
locked and limited conversation to collaborators
Jun 12, 2026
Sign up for freeto subscribe to this conversation on GitHub.
Already have an account?
Sign in.


Reviewers

Copilot code reviewCopilot
Copilot review effort
Applies to this pull request for everyone.Learn more about Copilot code review.
Copilot left review comments
@lateralusXlateralusXlateralusX approved these changes
@jakobbotschjakobbotschAwaiting requested review from jakobbotsch

Assignees

@rcj1rcj1

Labels

area-Diagnostics-coreclr

Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

3 participants

@rcj1@lateralusX

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[runtime-async] Fix timestamp instrumentation - #127662
Merged
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
May 12, 2026
Merged
[runtime-async] Fix timestamp instrumentation#127662
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
Conversation
@rcj1
@rcj1rcj1
commented
May 1, 2026•

edited

Loading

Copy link


Copy Markdown

Contributor
  1. We need to ensure that new continuations are timestamped at suspension time. In an app with an async chain starting with, say, Main, curContinuation and newContinuation will both belong to Main upon resuming Main in DispatchContinuations. The async chain in t_runtimeAsyncAwaitState.SentinelContinuation!.Next has been built by the JIT via AsyncSuspend and contains newly allocated continuations for the methods above Main in the stack. These should receive a new timestamp, not that of Main.
  2. I don't think we need to add timestamps in QueueContinuationFollowUpActionIfNecessary; they have already been added in HandleSuspended.
Fixes the issue of all the timestamps being the same.

Benchmark #123727 (comment):

New: 387.4 ms

Old: 404.2 ms
@rcj1rcj1
changed the title
Fix timestamp instrumentation[runtime-async] Fix timestamp instrumentationMay 1, 2026
@dotnet-policy-service
dotnet-policy-serviceBot
commented
May 1, 2026

Copy link


Copy Markdown

Contributor
Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag

See info in area-owners.md if you want to be subscribed.
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
This PR adjusts the runtime-async async-debugger instrumentation so that newly-created continuation chains get fresh timestamps at suspension time (instead of inheriting the timestamp of the currently-running continuation), and removes now-unneeded timestamp propagation logic tied to follow-up scheduling.
Changes:
  • Removed the Task.TryAddRuntimeAsyncContinuationChainTimestamps(Continuation chain, Continuation timestampSource) overload to avoid propagating an “old” timestamp to newly allocated continuation nodes.
  • Simplified AsyncDebugger.HandleSuspended / InstrumentedHandleSuspended to always timestamp based on the suspended chain head (sentinel’s Next) without a separate timestamp source.
  • Removed the SuspendRuntimeAsyncContext(ref AsyncDispatcherInfo, ...) / SuspendAsyncContext(ref AsyncDispatcherInfo, ...) path that previously timestamped the remaining chain when a follow-up continuation was queued.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.csRemoves the timestamp-source-based chain timestamping helper, leaving chain timestamping to use a fresh suspension-time timestamp.
src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.csUpdates runtime-async instrumentation to timestamp suspended chains without using a “source continuation”, and removes the follow-up-action timestamping/suspend helper calls.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
CopilotAI
review requested due to automatic review settings
May 1, 2026 20:59
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
You will need to rebase and test this on top of #127238.
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
We should probably also add some test to see if we could guard this specific scenario as well.
CopilotAI
review requested due to automatic review settings
May 5, 2026 19:20
CopilotAI
reviewed
May 5, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.
Comment thread...time/tests/System.Threading.Tasks.Tests/System.Runtime.CompilerServices/RuntimeAsyncTests.cs
lateralusX
lateralusX
approved these changes
May 12, 2026
View reviewed changes
@lateralusXlateralusX
left a comment


Copy link


Copy Markdown

Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM!
@rcj1
rcj1
commented
May 12, 2026

Copy link


Copy Markdown

ContributorAuthor
/ba-g timeouts
@rcj1
rcj1
merged commit 408f6a0
into
dotnet:mainMay 12, 2026

150 of 153 checks passed

@rcj1
rcj1
deleted the

fix-timestamps

branch
May 12, 2026 17:14
@dotnet-maestrodotnet-maestroBot
mentioned this pull request
May 12, 2026
 Merged


This was referenced Jun 2, 2026
 Closed

 Closed

@github-actionsgithub-actionsBot
locked and limited conversation to collaborators
Jun 12, 2026
Sign up for freeto subscribe to this conversation on GitHub.
Already have an account?
Sign in.


Reviewers

Copilot code reviewCopilot
Copilot review effort
Applies to this pull request for everyone.Learn more about Copilot code review.
Copilot left review comments
@lateralusXlateralusXlateralusX approved these changes
@jakobbotschjakobbotschAwaiting requested review from jakobbotsch

Assignees

@rcj1rcj1

Labels

area-Diagnostics-coreclr

Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

3 participants

@rcj1@lateralusX

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[runtime-async] Fix timestamp instrumentation - #127662
Merged
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
May 12, 2026
Merged
[runtime-async] Fix timestamp instrumentation#127662
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
Conversation
@rcj1
@rcj1rcj1
commented
May 1, 2026•

edited

Loading

Copy link


Copy Markdown

Contributor
  1. We need to ensure that new continuations are timestamped at suspension time. In an app with an async chain starting with, say, Main, curContinuation and newContinuation will both belong to Main upon resuming Main in DispatchContinuations. The async chain in t_runtimeAsyncAwaitState.SentinelContinuation!.Next has been built by the JIT via AsyncSuspend and contains newly allocated continuations for the methods above Main in the stack. These should receive a new timestamp, not that of Main.
  2. I don't think we need to add timestamps in QueueContinuationFollowUpActionIfNecessary; they have already been added in HandleSuspended.
Fixes the issue of all the timestamps being the same.

Benchmark #123727 (comment):

New: 387.4 ms

Old: 404.2 ms
@rcj1rcj1
changed the title
Fix timestamp instrumentation[runtime-async] Fix timestamp instrumentationMay 1, 2026
@dotnet-policy-service
dotnet-policy-serviceBot
commented
May 1, 2026

Copy link


Copy Markdown

Contributor
Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag

See info in area-owners.md if you want to be subscribed.
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
This PR adjusts the runtime-async async-debugger instrumentation so that newly-created continuation chains get fresh timestamps at suspension time (instead of inheriting the timestamp of the currently-running continuation), and removes now-unneeded timestamp propagation logic tied to follow-up scheduling.
Changes:
  • Removed the Task.TryAddRuntimeAsyncContinuationChainTimestamps(Continuation chain, Continuation timestampSource) overload to avoid propagating an “old” timestamp to newly allocated continuation nodes.
  • Simplified AsyncDebugger.HandleSuspended / InstrumentedHandleSuspended to always timestamp based on the suspended chain head (sentinel’s Next) without a separate timestamp source.
  • Removed the SuspendRuntimeAsyncContext(ref AsyncDispatcherInfo, ...) / SuspendAsyncContext(ref AsyncDispatcherInfo, ...) path that previously timestamped the remaining chain when a follow-up continuation was queued.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.csRemoves the timestamp-source-based chain timestamping helper, leaving chain timestamping to use a fresh suspension-time timestamp.
src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.csUpdates runtime-async instrumentation to timestamp suspended chains without using a “source continuation”, and removes the follow-up-action timestamping/suspend helper calls.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
CopilotAI
review requested due to automatic review settings
May 1, 2026 20:59
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
You will need to rebase and test this on top of #127238.
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
We should probably also add some test to see if we could guard this specific scenario as well.
CopilotAI
review requested due to automatic review settings
May 5, 2026 19:20
CopilotAI
reviewed
May 5, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.
Comment thread...time/tests/System.Threading.Tasks.Tests/System.Runtime.CompilerServices/RuntimeAsyncTests.cs
lateralusX
lateralusX
approved these changes
May 12, 2026
View reviewed changes
@lateralusXlateralusX
left a comment


Copy link


Copy Markdown

Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM!
@rcj1
rcj1
commented
May 12, 2026

Copy link


Copy Markdown

ContributorAuthor
/ba-g timeouts
@rcj1
rcj1
merged commit 408f6a0
into
dotnet:mainMay 12, 2026

150 of 153 checks passed

@rcj1
rcj1
deleted the

fix-timestamps

branch
May 12, 2026 17:14
@dotnet-maestrodotnet-maestroBot
mentioned this pull request
May 12, 2026
 Merged


This was referenced Jun 2, 2026
 Closed

 Closed

@github-actionsgithub-actionsBot
locked and limited conversation to collaborators
Jun 12, 2026
Sign up for freeto subscribe to this conversation on GitHub.
Already have an account?
Sign in.


Reviewers

Copilot code reviewCopilot
Copilot review effort
Applies to this pull request for everyone.Learn more about Copilot code review.
Copilot left review comments
@lateralusXlateralusXlateralusX approved these changes
@jakobbotschjakobbotschAwaiting requested review from jakobbotsch

Assignees

@rcj1rcj1

Labels

area-Diagnostics-coreclr

Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

3 participants

@rcj1@lateralusX

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
[runtime-async] Fix timestamp instrumentation - #127662
Merged
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
May 12, 2026
Merged
[runtime-async] Fix timestamp instrumentation#127662
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
Conversation
@rcj1
@rcj1rcj1
commented
May 1, 2026•

edited

Loading

Copy link


Copy Markdown

Contributor
  1. We need to ensure that new continuations are timestamped at suspension time. In an app with an async chain starting with, say, Main, curContinuation and newContinuation will both belong to Main upon resuming Main in DispatchContinuations. The async chain in t_runtimeAsyncAwaitState.SentinelContinuation!.Next has been built by the JIT via AsyncSuspend and contains newly allocated continuations for the methods above Main in the stack. These should receive a new timestamp, not that of Main.
  2. I don't think we need to add timestamps in QueueContinuationFollowUpActionIfNecessary; they have already been added in HandleSuspended.
Fixes the issue of all the timestamps being the same.

Benchmark #123727 (comment):

New: 387.4 ms

Old: 404.2 ms
@rcj1rcj1
changed the title
Fix timestamp instrumentation[runtime-async] Fix timestamp instrumentationMay 1, 2026
@dotnet-policy-service
dotnet-policy-serviceBot
commented
May 1, 2026

Copy link


Copy Markdown

Contributor
Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag

See info in area-owners.md if you want to be subscribed.
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
This PR adjusts the runtime-async async-debugger instrumentation so that newly-created continuation chains get fresh timestamps at suspension time (instead of inheriting the timestamp of the currently-running continuation), and removes now-unneeded timestamp propagation logic tied to follow-up scheduling.
Changes:
  • Removed the Task.TryAddRuntimeAsyncContinuationChainTimestamps(Continuation chain, Continuation timestampSource) overload to avoid propagating an “old” timestamp to newly allocated continuation nodes.
  • Simplified AsyncDebugger.HandleSuspended / InstrumentedHandleSuspended to always timestamp based on the suspended chain head (sentinel’s Next) without a separate timestamp source.
  • Removed the SuspendRuntimeAsyncContext(ref AsyncDispatcherInfo, ...) / SuspendAsyncContext(ref AsyncDispatcherInfo, ...) path that previously timestamped the remaining chain when a follow-up continuation was queued.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.csRemoves the timestamp-source-based chain timestamping helper, leaving chain timestamping to use a fresh suspension-time timestamp.
src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.csUpdates runtime-async instrumentation to timestamp suspended chains without using a “source continuation”, and removes the follow-up-action timestamping/suspend helper calls.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
CopilotAI
review requested due to automatic review settings
May 1, 2026 20:59
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
You will need to rebase and test this on top of #127238.
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
We should probably also add some test to see if we could guard this specific scenario as well.
CopilotAI
review requested due to automatic review settings
May 5, 2026 19:20
CopilotAI
reviewed
May 5, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.
Comment thread...time/tests/System.Threading.Tasks.Tests/System.Runtime.CompilerServices/RuntimeAsyncTests.cs
lateralusX
lateralusX
approved these changes
May 12, 2026
View reviewed changes
@lateralusXlateralusX
left a comment


Copy link


Copy Markdown

Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM!
@rcj1
rcj1
commented
May 12, 2026

Copy link


Copy Markdown

ContributorAuthor
/ba-g timeouts
@rcj1
rcj1
merged commit 408f6a0
into
dotnet:mainMay 12, 2026

150 of 153 checks passed

@rcj1
rcj1
deleted the

fix-timestamps

branch
May 12, 2026 17:14
@dotnet-maestrodotnet-maestroBot
mentioned this pull request
May 12, 2026
 Merged


This was referenced Jun 2, 2026
 Closed

 Closed

@github-actionsgithub-actionsBot
locked and limited conversation to collaborators
Jun 12, 2026
Sign up for freeto subscribe to this conversation on GitHub.
Already have an account?
Sign in.


Reviewers

Copilot code reviewCopilot
Copilot review effort
Applies to this pull request for everyone.Learn more about Copilot code review.
Copilot left review comments
@lateralusXlateralusXlateralusX approved these changes
@jakobbotschjakobbotschAwaiting requested review from jakobbotsch

Assignees

@rcj1rcj1

Labels

area-Diagnostics-coreclr

Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

3 participants

@rcj1@lateralusX

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[runtime-async] Fix timestamp instrumentation - #127662
Merged
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
May 12, 2026
Merged
[runtime-async] Fix timestamp instrumentation#127662
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
Conversation
@rcj1
@rcj1rcj1
commented
May 1, 2026•

edited

Loading

Copy link


Copy Markdown

Contributor
  1. We need to ensure that new continuations are timestamped at suspension time. In an app with an async chain starting with, say, Main, curContinuation and newContinuation will both belong to Main upon resuming Main in DispatchContinuations. The async chain in t_runtimeAsyncAwaitState.SentinelContinuation!.Next has been built by the JIT via AsyncSuspend and contains newly allocated continuations for the methods above Main in the stack. These should receive a new timestamp, not that of Main.
  2. I don't think we need to add timestamps in QueueContinuationFollowUpActionIfNecessary; they have already been added in HandleSuspended.
Fixes the issue of all the timestamps being the same.

Benchmark #123727 (comment):

New: 387.4 ms

Old: 404.2 ms
@rcj1rcj1
changed the title
Fix timestamp instrumentation[runtime-async] Fix timestamp instrumentationMay 1, 2026
@dotnet-policy-service
dotnet-policy-serviceBot
commented
May 1, 2026

Copy link


Copy Markdown

Contributor
Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag

See info in area-owners.md if you want to be subscribed.
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
This PR adjusts the runtime-async async-debugger instrumentation so that newly-created continuation chains get fresh timestamps at suspension time (instead of inheriting the timestamp of the currently-running continuation), and removes now-unneeded timestamp propagation logic tied to follow-up scheduling.
Changes:
  • Removed the Task.TryAddRuntimeAsyncContinuationChainTimestamps(Continuation chain, Continuation timestampSource) overload to avoid propagating an “old” timestamp to newly allocated continuation nodes.
  • Simplified AsyncDebugger.HandleSuspended / InstrumentedHandleSuspended to always timestamp based on the suspended chain head (sentinel’s Next) without a separate timestamp source.
  • Removed the SuspendRuntimeAsyncContext(ref AsyncDispatcherInfo, ...) / SuspendAsyncContext(ref AsyncDispatcherInfo, ...) path that previously timestamped the remaining chain when a follow-up continuation was queued.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.csRemoves the timestamp-source-based chain timestamping helper, leaving chain timestamping to use a fresh suspension-time timestamp.
src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.csUpdates runtime-async instrumentation to timestamp suspended chains without using a “source continuation”, and removes the follow-up-action timestamping/suspend helper calls.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
CopilotAI
review requested due to automatic review settings
May 1, 2026 20:59
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
You will need to rebase and test this on top of #127238.
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
We should probably also add some test to see if we could guard this specific scenario as well.
CopilotAI
review requested due to automatic review settings
May 5, 2026 19:20
CopilotAI
reviewed
May 5, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.
Comment thread...time/tests/System.Threading.Tasks.Tests/System.Runtime.CompilerServices/RuntimeAsyncTests.cs
lateralusX
lateralusX
approved these changes
May 12, 2026
View reviewed changes
@lateralusXlateralusX
left a comment


Copy link


Copy Markdown

Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM!
@rcj1
rcj1
commented
May 12, 2026

Copy link


Copy Markdown

ContributorAuthor
/ba-g timeouts
@rcj1
rcj1
merged commit 408f6a0
into
dotnet:mainMay 12, 2026

150 of 153 checks passed

@rcj1
rcj1
deleted the

fix-timestamps

branch
May 12, 2026 17:14
@dotnet-maestrodotnet-maestroBot
mentioned this pull request
May 12, 2026
 Merged


This was referenced Jun 2, 2026
 Closed

 Closed

@github-actionsgithub-actionsBot
locked and limited conversation to collaborators
Jun 12, 2026
Sign up for freeto subscribe to this conversation on GitHub.
Already have an account?
Sign in.


Reviewers

Copilot code reviewCopilot
Copilot review effort
Applies to this pull request for everyone.Learn more about Copilot code review.
Copilot left review comments
@lateralusXlateralusXlateralusX approved these changes
@jakobbotschjakobbotschAwaiting requested review from jakobbotsch

Assignees

@rcj1rcj1

Labels

area-Diagnostics-coreclr

Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

3 participants

@rcj1@lateralusX

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[runtime-async] Fix timestamp instrumentation - #127662
Merged
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
May 12, 2026
Merged
[runtime-async] Fix timestamp instrumentation#127662
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
Conversation
@rcj1
@rcj1rcj1
commented
May 1, 2026•

edited

Loading

Copy link


Copy Markdown

Contributor
  1. We need to ensure that new continuations are timestamped at suspension time. In an app with an async chain starting with, say, Main, curContinuation and newContinuation will both belong to Main upon resuming Main in DispatchContinuations. The async chain in t_runtimeAsyncAwaitState.SentinelContinuation!.Next has been built by the JIT via AsyncSuspend and contains newly allocated continuations for the methods above Main in the stack. These should receive a new timestamp, not that of Main.
  2. I don't think we need to add timestamps in QueueContinuationFollowUpActionIfNecessary; they have already been added in HandleSuspended.
Fixes the issue of all the timestamps being the same.

Benchmark #123727 (comment):

New: 387.4 ms

Old: 404.2 ms
@rcj1rcj1
changed the title
Fix timestamp instrumentation[runtime-async] Fix timestamp instrumentationMay 1, 2026
@dotnet-policy-service
dotnet-policy-serviceBot
commented
May 1, 2026

Copy link


Copy Markdown

Contributor
Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag

See info in area-owners.md if you want to be subscribed.
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
This PR adjusts the runtime-async async-debugger instrumentation so that newly-created continuation chains get fresh timestamps at suspension time (instead of inheriting the timestamp of the currently-running continuation), and removes now-unneeded timestamp propagation logic tied to follow-up scheduling.
Changes:
  • Removed the Task.TryAddRuntimeAsyncContinuationChainTimestamps(Continuation chain, Continuation timestampSource) overload to avoid propagating an “old” timestamp to newly allocated continuation nodes.
  • Simplified AsyncDebugger.HandleSuspended / InstrumentedHandleSuspended to always timestamp based on the suspended chain head (sentinel’s Next) without a separate timestamp source.
  • Removed the SuspendRuntimeAsyncContext(ref AsyncDispatcherInfo, ...) / SuspendAsyncContext(ref AsyncDispatcherInfo, ...) path that previously timestamped the remaining chain when a follow-up continuation was queued.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.csRemoves the timestamp-source-based chain timestamping helper, leaving chain timestamping to use a fresh suspension-time timestamp.
src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.csUpdates runtime-async instrumentation to timestamp suspended chains without using a “source continuation”, and removes the follow-up-action timestamping/suspend helper calls.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
CopilotAI
review requested due to automatic review settings
May 1, 2026 20:59
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
You will need to rebase and test this on top of #127238.
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
We should probably also add some test to see if we could guard this specific scenario as well.
CopilotAI
review requested due to automatic review settings
May 5, 2026 19:20
CopilotAI
reviewed
May 5, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.
Comment thread...time/tests/System.Threading.Tasks.Tests/System.Runtime.CompilerServices/RuntimeAsyncTests.cs
lateralusX
lateralusX
approved these changes
May 12, 2026
View reviewed changes
@lateralusXlateralusX
left a comment


Copy link


Copy Markdown

Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM!
@rcj1
rcj1
commented
May 12, 2026

Copy link


Copy Markdown

ContributorAuthor
/ba-g timeouts
@rcj1
rcj1
merged commit 408f6a0
into
dotnet:mainMay 12, 2026

150 of 153 checks passed

@rcj1
rcj1
deleted the

fix-timestamps

branch
May 12, 2026 17:14
@dotnet-maestrodotnet-maestroBot
mentioned this pull request
May 12, 2026
 Merged


This was referenced Jun 2, 2026
 Closed

 Closed

@github-actionsgithub-actionsBot
locked and limited conversation to collaborators
Jun 12, 2026
Sign up for freeto subscribe to this conversation on GitHub.
Already have an account?
Sign in.


Reviewers

Copilot code reviewCopilot
Copilot review effort
Applies to this pull request for everyone.Learn more about Copilot code review.
Copilot left review comments
@lateralusXlateralusXlateralusX approved these changes
@jakobbotschjakobbotschAwaiting requested review from jakobbotsch

Assignees

@rcj1rcj1

Labels

area-Diagnostics-coreclr

Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

3 participants

@rcj1@lateralusX

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
[runtime-async] Fix timestamp instrumentation - #127662
Merged
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
May 12, 2026
Merged
[runtime-async] Fix timestamp instrumentation#127662
rcj1 merged 6 commits into
dotnet:mainfrom 
rcj1:fix-timestamps
Conversation
@rcj1
@rcj1rcj1
commented
May 1, 2026•

edited

Loading

Copy link


Copy Markdown

Contributor
  1. We need to ensure that new continuations are timestamped at suspension time. In an app with an async chain starting with, say, Main, curContinuation and newContinuation will both belong to Main upon resuming Main in DispatchContinuations. The async chain in t_runtimeAsyncAwaitState.SentinelContinuation!.Next has been built by the JIT via AsyncSuspend and contains newly allocated continuations for the methods above Main in the stack. These should receive a new timestamp, not that of Main.
  2. I don't think we need to add timestamps in QueueContinuationFollowUpActionIfNecessary; they have already been added in HandleSuspended.
Fixes the issue of all the timestamps being the same.

Benchmark #123727 (comment):

New: 387.4 ms

Old: 404.2 ms
@rcj1rcj1
changed the title
Fix timestamp instrumentation[runtime-async] Fix timestamp instrumentationMay 1, 2026
@dotnet-policy-service
dotnet-policy-serviceBot
commented
May 1, 2026

Copy link


Copy Markdown

Contributor
Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag

See info in area-owners.md if you want to be subscribed.
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
This PR adjusts the runtime-async async-debugger instrumentation so that newly-created continuation chains get fresh timestamps at suspension time (instead of inheriting the timestamp of the currently-running continuation), and removes now-unneeded timestamp propagation logic tied to follow-up scheduling.
Changes:
  • Removed the Task.TryAddRuntimeAsyncContinuationChainTimestamps(Continuation chain, Continuation timestampSource) overload to avoid propagating an “old” timestamp to newly allocated continuation nodes.
  • Simplified AsyncDebugger.HandleSuspended / InstrumentedHandleSuspended to always timestamp based on the suspended chain head (sentinel’s Next) without a separate timestamp source.
  • Removed the SuspendRuntimeAsyncContext(ref AsyncDispatcherInfo, ...) / SuspendAsyncContext(ref AsyncDispatcherInfo, ...) path that previously timestamped the remaining chain when a follow-up continuation was queued.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.csRemoves the timestamp-source-based chain timestamping helper, leaving chain timestamping to use a fresh suspension-time timestamp.
src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.csUpdates runtime-async instrumentation to timestamp suspended chains without using a “source continuation”, and removes the follow-up-action timestamping/suspend helper calls.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
CopilotAI
review requested due to automatic review settings
May 1, 2026 20:59
CopilotAI
reviewed
May 1, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
Comment threadsrc/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
You will need to rebase and test this on top of #127238.
@lateralusX
lateralusX
commented
May 4, 2026

Copy link


Copy Markdown

Member
We should probably also add some test to see if we could guard this specific scenario as well.
CopilotAI
review requested due to automatic review settings
May 5, 2026 19:20
CopilotAI
reviewed
May 5, 2026
View reviewed changes
CopilotAI
left a comment


Copy link


Copy Markdown

Contributor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview
Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.
Comment thread...time/tests/System.Threading.Tasks.Tests/System.Runtime.CompilerServices/RuntimeAsyncTests.cs
lateralusX
lateralusX
approved these changes
May 12, 2026
View reviewed changes
@lateralusXlateralusX
left a comment


Copy link


Copy Markdown

Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM!
@rcj1
rcj1
commented
May 12, 2026

Copy link


Copy Markdown

ContributorAuthor
/ba-g timeouts
@rcj1
rcj1
merged commit 408f6a0
into
dotnet:mainMay 12, 2026

150 of 153 checks passed

@rcj1
rcj1
deleted the

fix-timestamps

branch
May 12, 2026 17:14
@dotnet-maestrodotnet-maestroBot
mentioned this pull request
May 12, 2026
 Merged


This was referenced Jun 2, 2026
 Closed

 Closed

@github-actionsgithub-actionsBot
locked and limited conversation to collaborators
Jun 12, 2026
Sign up for freeto subscribe to this conversation on GitHub.
Already have an account?
Sign in.


Reviewers

Copilot code reviewCopilot
Copilot review effort
Applies to this pull request for everyone.Learn more about Copilot code review.
Copilot left review comments
@lateralusXlateralusXlateralusX approved these changes
@jakobbotschjakobbotschAwaiting requested review from jakobbotsch

Assignees

@rcj1rcj1

Labels

area-Diagnostics-coreclr

Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

3 participants

@rcj1@lateralusX