events: improve events performance by rluvaton · Pull Request #50422 · nodejs/node

rluvaton · 2023-10-27T08:41:37Z

Benchmarks

Change `_events` to be a `Map`:

commit: 249c2b8

Notes:

I'm afraid this can break userland implementation of EventEmitter that are using node EventEmitter class functions (cc @ronag )
This also improves creation by a lot (and therefore improves streams creation)

15:31:01 confidence improvement accuracy (*) (**) (***)
15:31:01 events/ee-add-remove.js n=1000000 removeListener=0 newListener=0 *** 19.64 % ±1.57% ±2.09% ±2.73%
15:31:01 events/ee-add-remove.js n=1000000 removeListener=0 newListener=1 *** 46.84 % ±2.02% ±2.70% ±3.54%
15:31:01 events/ee-add-remove.js n=1000000 removeListener=1 newListener=0 *** 45.01 % ±2.68% ±3.60% ±4.75%
15:31:01 events/ee-add-remove.js n=1000000 removeListener=1 newListener=1 *** 56.27 % ±2.72% ±3.64% ±4.79%
15:31:01 events/ee-emit.js listeners=1 argc=0 n=2000000 *** 32.42 % ±9.82% ±13.07% ±17.02%
15:31:01 events/ee-emit.js listeners=1 argc=10 n=2000000 *** 36.00 % ±8.08% ±10.75% ±14.00%
15:31:01 events/ee-emit.js listeners=1 argc=2 n=2000000 *** 23.57 % ±9.57% ±12.75% ±16.62%
15:31:01 events/ee-emit.js listeners=1 argc=4 n=2000000 *** 28.33 % ±8.95% ±11.92% ±15.52%
15:31:01 events/ee-emit.js listeners=10 argc=0 n=2000000 4.48 % ±7.03% ±9.35% ±12.17%
15:31:01 events/ee-emit.js listeners=10 argc=10 n=2000000 0.02 % ±4.28% ±5.70% ±7.42%
15:31:01 events/ee-emit.js listeners=10 argc=2 n=2000000 ** -6.22 % ±4.54% ±6.06% ±7.91%
15:31:01 events/ee-emit.js listeners=10 argc=4 n=2000000 ** 6.55 % ±4.59% ±6.13% ±8.00%
15:31:01 events/ee-emit.js listeners=5 argc=0 n=2000000 1.39 % ±9.30% ±12.37% ±16.11%
15:31:01 events/ee-emit.js listeners=5 argc=10 n=2000000 -0.34 % ±7.02% ±9.35% ±12.18%
15:31:01 events/ee-emit.js listeners=5 argc=2 n=2000000 5.45 % ±8.85% ±11.78% ±15.33%
15:31:01 events/ee-emit.js listeners=5 argc=4 n=2000000 0.79 % ±8.60% ±11.44% ±14.89%
15:31:01 events/ee-listen-unique.js n=1000000 events=1 *** 30.56 % ±2.05% ±2.73% ±3.56%
15:31:01 events/ee-listen-unique.js n=1000000 events=10 *** 13.34 % ±1.21% ±1.62% ±2.11%
15:31:01 events/ee-listen-unique.js n=1000000 events=2 *** 18.32 % ±1.99% ±2.67% ±3.51%
15:31:01 events/ee-listen-unique.js n=1000000 events=20 *** 13.37 % ±1.22% ±1.62% ±2.12%
15:31:01 events/ee-listen-unique.js n=1000000 events=3 *** 19.46 % ±1.15% ±1.53% ±2.00%
15:31:01 events/ee-listen-unique.js n=1000000 events=5 *** 15.05 % ±1.35% ±1.80% ±2.35%
15:31:01 events/ee-listener-count-on-prototype.js n=50000000 *** 29.98 % ±5.74% ±7.70% ±10.14%
15:31:01 events/ee-listeners.js raw='false' listeners=5 n=5000000 -2.69 % ±7.61% ±10.13% ±13.18%
15:31:01 events/ee-listeners.js raw='false' listeners=50 n=5000000 0.48 % ±1.82% ±2.42% ±3.15%
15:31:01 events/ee-listeners.js raw='true' listeners=5 n=5000000 6.34 % ±8.35% ±11.12% ±14.49%
15:31:01 events/ee-listeners.js raw='true' listeners=50 n=5000000 -1.34 % ±4.45% ±5.92% ±7.71%
15:31:01 events/ee-once.js argc=0 n=20000000 *** 31.26 % ±1.10% ±1.47% ±1.94%
15:31:01 events/ee-once.js argc=1 n=20000000 *** 26.62 % ±0.60% ±0.80% ±1.04%
15:31:01 events/ee-once.js argc=4 n=20000000 *** 26.93 % ±0.65% ±0.86% ±1.12%
15:31:01 events/ee-once.js argc=5 n=20000000 *** 27.19 % ±0.76% ±1.02% ±1.32%
15:31:01 events/eventtarget-add-remove.js nListener=10 n=1000000 *** 0.92 % ±0.38% ±0.51% ±0.66%
15:31:01 events/eventtarget-add-remove.js nListener=5 n=1000000 * 0.87 % ±0.69% ±0.91% ±1.19%
15:31:01 events/eventtarget-creation.js n=1000000 0.60 % ±5.04% ±6.70% ±8.73%
15:31:01 events/eventtarget.js listeners=1 n=1000000 0.90 % ±6.28% ±8.35% ±10.87%
15:31:01 events/eventtarget.js listeners=10 n=1000000 0.45 % ±3.51% ±4.68% ±6.09%
15:31:01 events/eventtarget.js listeners=5 n=1000000 0.21 % ±4.80% ±6.39% ±8.31%
15:31:01 15:31:01 Be aware that when doing many comparisons the risk of a false-positive
15:31:01 result increases. In this case, there are 37 comparisons, you can thus
15:31:01 expect the following amount of false-positive results:
15:31:01 1.85 false positives, when considering a 5% risk acceptance (*, **, ***),
15:31:01 0.37 false positives, when considering a 1% risk acceptance (**, ***),
15:31:01 0.04 false positives, when considering a 0.1% risk acceptance (***)

I run it on streams as well to see the impact as this was my original intent: url

Change to `Map` todos:

move all our internal code away from _events and use [kEvents] instead
I saw undici used _events so need to migrate as well

~~change _events to be without __proto__: null~~

change `_events` to be without `proto: null`

Commit: eb29e97

I think the performance without proto is not fully representative as the event name can be anything so the dictionary mode is not used here

Benchmark URL

12:55:39 ++ Rscript benchmark/compare.R
12:55:40 confidence improvement accuracy (*) (**) (***)
12:55:40 events/ee-add-remove.js n=1000000 removeListener=0 newListener=0 ** -2.22 % ±1.50% ±2.00% ±2.60%
12:55:40 events/ee-add-remove.js n=1000000 removeListener=0 newListener=1 *** 30.34 % ±1.75% ±2.33% ±3.04%
12:55:40 events/ee-add-remove.js n=1000000 removeListener=1 newListener=0 *** 22.74 % ±1.17% ±1.56% ±2.03%
12:55:40 events/ee-add-remove.js n=1000000 removeListener=1 newListener=1 *** 10.04 % ±1.11% ±1.47% ±1.92%
12:55:40 events/ee-emit.js listeners=1 argc=0 n=2000000 *** 159.54 % ±8.72% ±11.64% ±15.20%
12:55:40 events/ee-emit.js listeners=1 argc=10 n=2000000 *** 139.14 % ±12.44% ±16.59% ±21.66%
12:55:40 events/ee-emit.js listeners=1 argc=2 n=2000000 *** 159.56 % ±13.83% ±18.46% ±24.15%
12:55:40 events/ee-emit.js listeners=1 argc=4 n=2000000 *** 148.52 % ±10.04% ±13.37% ±17.43%
12:55:40 events/ee-emit.js listeners=10 argc=0 n=2000000 *** 13.34 % ±7.48% ±9.96% ±12.96%
12:55:40 events/ee-emit.js listeners=10 argc=10 n=2000000 *** 11.22 % ±5.66% ±7.53% ±9.81%
12:55:40 events/ee-emit.js listeners=10 argc=2 n=2000000 3.11 % ±6.21% ±8.27% ±10.77%
12:55:40 events/ee-emit.js listeners=10 argc=4 n=2000000 *** 12.07 % ±6.04% ±8.04% ±10.47%
12:55:40 events/ee-emit.js listeners=5 argc=0 n=2000000 *** 20.76 % ±9.34% ±12.44% ±16.24%
12:55:40 events/ee-emit.js listeners=5 argc=10 n=2000000 *** 17.29 % ±8.71% ±11.59% ±15.10%
12:55:40 events/ee-emit.js listeners=5 argc=2 n=2000000 * 13.10 % ±9.93% ±13.21% ±17.20%
12:55:40 events/ee-emit.js listeners=5 argc=4 n=2000000 * 9.82 % ±9.51% ±12.66% ±16.48%
12:55:40 events/ee-listen-unique.js n=1000000 events=1 0.24 % ±1.32% ±1.76% ±2.29%
12:55:40 events/ee-listen-unique.js n=1000000 events=10 *** -3.02 % ±1.08% ±1.44% ±1.88%
12:55:40 events/ee-listen-unique.js n=1000000 events=2 *** -2.28 % ±0.69% ±0.92% ±1.20%
12:55:40 events/ee-listen-unique.js n=1000000 events=20 ** -2.16 % ±1.56% ±2.09% ±2.73%
12:55:40 events/ee-listen-unique.js n=1000000 events=3 *** -2.03 % ±0.98% ±1.31% ±1.71%
12:55:40 events/ee-listen-unique.js n=1000000 events=5 *** -4.36 % ±0.89% ±1.19% ±1.55%
12:55:40 events/ee-listener-count-on-prototype.js n=50000000 *** -6.40 % ±3.40% ±4.53% ±5.91%
12:55:40 events/ee-listeners.js raw='false' listeners=5 n=5000000 * -8.30 % ±6.34% ±8.45% ±11.02%
12:55:40 events/ee-listeners.js raw='false' listeners=50 n=5000000 -1.08 % ±1.71% ±2.28% ±2.97%
12:55:40 events/ee-listeners.js raw='true' listeners=5 n=5000000 -3.00 % ±5.69% ±7.58% ±9.89%
12:55:40 events/ee-listeners.js raw='true' listeners=50 n=5000000 3.68 % ±4.65% ±6.18% ±8.05%
12:55:40 events/ee-once.js argc=0 n=20000000 -0.21 % ±0.64% ±0.85% ±1.10%
12:55:40 events/ee-once.js argc=1 n=20000000 0.06 % ±0.44% ±0.59% ±0.76%
12:55:40 events/ee-once.js argc=4 n=20000000 -0.13 % ±0.62% ±0.83% ±1.08%
12:55:40 events/ee-once.js argc=5 n=20000000 0.26 % ±0.69% ±0.91% ±1.19%
12:55:40 events/eventtarget-add-remove.js nListener=10 n=1000000 ** 0.71 % ±0.42% ±0.56% ±0.73%
12:55:40 events/eventtarget-add-remove.js nListener=5 n=1000000 0.30 % ±0.70% ±0.94% ±1.22%
12:55:40 events/eventtarget-creation.js n=1000000 1.95 % ±3.80% ±5.09% ±6.72%
12:55:40 events/eventtarget.js listeners=1 n=1000000 -0.66 % ±5.51% ±7.34% ±9.55%
12:55:40 events/eventtarget.js listeners=10 n=1000000 -0.32 % ±3.15% ±4.19% ±5.46%
12:55:40 events/eventtarget.js listeners=5 n=1000000 -0.39 % ±5.18% ±6.90% ±8.98%
12:55:40 12:55:40 Be aware that when doing many comparisons the risk of a false-positive
12:55:40 result increases. In this case, there are 37 comparisons, you can thus
12:55:40 expect the following amount of false-positive results:
12:55:40 1.85 false positives, when considering a 5% risk acceptance (*, **, ***),
12:55:40 0.37 false positives, when considering a 1% risk acceptance (**, ***),
12:55:40 0.04 false positives, when considering a 0.1% risk acceptance (***)

nodejs-github-bot · 2023-10-27T11:07:06Z

CI: https://ci.nodejs.org/job/node-test-pull-request/55268/

ronag · 2023-10-27T13:42:41Z

This is probably going to break someone somewhere. That being said, maybe there is a way to minimize it by returning a Proxy from the _events getter that more accurately imitates the original behavior.

Also, I'm surprised this is so much faster. Often the same events are used (e.g. for streams), so I would assume that V8 uses a shape rather than a map behind the scenes, which should be faster than a Map instance. @benjamingr wdyt?

ronag · 2023-10-27T13:44:50Z

I'm actually not that interested in ee-listen-unique and ee-once.

rluvaton · 2023-10-27T13:45:31Z

Also, I'm surprised this is so much faster. Often the same events are used (e.g. for streams), so I would assume that V8 uses a shape rather than a map behind the scenes, which should be faster than a Map instance.

{ __proto__: null } hint v8 to use the dictionary mode src/runtime/runtime-literals.cc in V8 (founded by @benjamingr)

rluvaton · 2023-10-27T13:47:51Z

This is probably going to break someone somewhere. That being said, maybe there is a way to minimize it by returning a Proxy from the _events getter that more accurately imitates the original behavior.
Often the same events are used (e.g. for streams)

you can see the results when removing __proto__ null at the bottom (collapsed)

rluvaton · 2023-10-27T13:58:32Z

This is concerning:

16:57:40 confidence improvement accuracy (*) (**) (***)
16:57:40 streams/creation.js kind='duplex' n=50000000 ** 1.61 % ±0.93% ±1.23% ±1.61%
16:57:40 streams/creation.js kind='readable' n=50000000 *** -17.07 % ±0.68% ±0.91% ±1.19%
16:57:40 streams/creation.js kind='transform' n=50000000 *** 24.20 % ±1.46% ±1.95% ±2.55%
16:57:40 streams/creation.js kind='writable' n=50000000 0.54 % ±0.92% ±1.23% ±1.60%
16:57:40 streams/destroy.js kind='duplex' n=1000000 ** -3.85 % ±2.25% ±2.99% ±3.90%
16:57:40 streams/destroy.js kind='readable' n=1000000 -0.90 % ±1.66% ±2.21% ±2.88%
16:57:40 streams/destroy.js kind='transform' n=1000000 -1.38 % ±1.91% ±2.54% ±3.31%
16:57:40 streams/destroy.js kind='writable' n=1000000 -2.12 % ±2.19% ±2.91% ±3.80%
16:57:40 streams/pipe-object-mode.js n=5000000 * 6.22 % ±5.34% ±7.11% ±9.26%
16:57:40 streams/pipe.js n=5000000 *** 7.73 % ±3.87% ±5.15% ±6.70%
16:57:40 streams/readable-async-iterator.js sync='no' n=100000 -2.28 % ±6.37% ±8.48% ±11.05%
16:57:40 streams/readable-async-iterator.js sync='yes' n=100000 -0.80 % ±5.49% ±7.30% ±9.51%
16:57:40 streams/readable-bigread.js n=1000 * 3.49 % ±2.92% ±3.92% ±5.17%
16:57:40 streams/readable-bigunevenread.js n=1000 -0.62 % ±3.22% ±4.33% ±5.72%
16:57:40 streams/readable-boundaryread.js type='buffer' n=2000 *** 11.62 % ±1.13% ±1.50% ±1.95%
16:57:40 streams/readable-boundaryread.js type='string' n=2000 2.67 % ±3.46% ±4.61% ±6.03%
16:57:40 streams/readable-from.js type='array' n=10000000 4.68 % ±5.29% ±7.05% ±9.18%
16:57:40 streams/readable-from.js type='async-generator' n=10000000 *** 2.44 % ±0.90% ±1.20% ±1.56%
16:57:40 streams/readable-from.js type='sync-generator-with-async-values' n=10000000 *** 4.27 % ±0.99% ±1.32% ±1.71%
16:57:40 streams/readable-from.js type='sync-generator-with-sync-values' n=10000000 2.93 % ±4.20% ±5.59% ±7.28%
16:57:40 streams/readable-readall.js n=5000 -1.18 % ±6.06% ±8.06% ±10.50%
16:57:40 streams/readable-unevenread.js n=1000 *** 3.97 % ±2.02% ±2.68% ±3.49%
16:57:40 streams/writable-manywrites.js len=1024 callback='no' writev='no' sync='no' n=100000 *** -3.08 % ±1.04% ±1.38% ±1.79%
16:57:40 streams/writable-manywrites.js len=1024 callback='no' writev='no' sync='yes' n=100000 0.94 % ±1.97% ±2.63% ±3.43%
16:57:40 streams/writable-manywrites.js len=1024 callback='no' writev='yes' sync='no' n=100000 *** -6.76 % ±2.49% ±3.34% ±4.39%
16:57:40 streams/writable-manywrites.js len=1024 callback='no' writev='yes' sync='yes' n=100000 -3.66 % ±4.38% ±5.84% ±7.63%
16:57:40 streams/writable-manywrites.js len=1024 callback='yes' writev='no' sync='no' n=100000 -2.13 % ±3.01% ±4.01% ±5.22%
16:57:40 streams/writable-manywrites.js len=1024 callback='yes' writev='no' sync='yes' n=100000 -1.16 % ±2.15% ±2.86% ±3.72%
16:57:40 streams/writable-manywrites.js len=1024 callback='yes' writev='yes' sync='no' n=100000 *** -4.85 % ±2.67% ±3.56% ±4.66%
16:57:40 streams/writable-manywrites.js len=1024 callback='yes' writev='yes' sync='yes' n=100000 -1.77 % ±3.70% ±4.95% ±6.49%
16:57:40 streams/writable-manywrites.js len=32768 callback='no' writev='no' sync='no' n=100000 0.89 % ±3.28% ±4.39% ±5.76%
16:57:40 streams/writable-manywrites.js len=32768 callback='no' writev='no' sync='yes' n=100000 -1.94 % ±3.64% ±4.85% ±6.31%
16:57:40 streams/writable-manywrites.js len=32768 callback='no' writev='yes' sync='no' n=100000 * -1.35 % ±1.11% ±1.47% ±1.92%
16:57:40 streams/writable-manywrites.js len=32768 callback='no' writev='yes' sync='yes' n=100000 -2.63 % ±3.85% ±5.12% ±6.67%
16:57:40 streams/writable-manywrites.js len=32768 callback='yes' writev='no' sync='no' n=100000 1.63 % ±3.13% ±4.19% ±5.53%
16:57:40 streams/writable-manywrites.js len=32768 callback='yes' writev='no' sync='yes' n=100000 -1.37 % ±2.82% ±3.75% ±4.89%
16:57:40 streams/writable-manywrites.js len=32768 callback='yes' writev='yes' sync='no' n=100000 ** -1.50 % ±1.09% ±1.44% ±1.88%
16:57:40 streams/writable-manywrites.js len=32768 callback='yes' writev='yes' sync='yes' n=100000 -1.05 % ±2.24% ±2.98% ±3.88%
16:57:40 16:57:40 Be aware that when doing many comparisons the risk of a false-positive
16:57:40 result increases. In this case, there are 38 comparisons, you can thus
16:57:40 expect the following amount of false-positive results:
16:57:40 1.90 false positives, when considering a 5% risk acceptance (*, **, ***),
16:57:40 0.38 false positives, when considering a 1% risk acceptance (**, ***),
16:57:40 0.04 false positives, when considering a 0.1% risk acceptance (***)

benjamingr

This is neat but I don't understand how it's faster since objects in dictionary mode and maps have basically the same performance.

Also the "polyfill" for ._eventsis incorrect since if someone sets a value on it it won't get reflected in the emitter.

ronag · 2023-10-27T14:06:55Z

{ proto: null } hint v8 to use the dictionary mod

What happens if you remove that hint? Sorry it's a bit unclear what your last benchmark results are from.

rluvaton · 2023-10-27T14:09:58Z

Also the "polyfill" for ._eventsis incorrect since if someone sets a value on it it won't get reflected in the emitter.

I know I still have a todo there to convert to Proxy so it support everything

This is neat but I don't understand how it's faster since objects in dictionary mode and maps have basically the same performance.

Maybe because it by default go to the dict mode?

{ proto: null } hint v8 to use the dictionary mod
What happens if you remove that hint? Sorry it's a bit unclear what your last benchmark results are from.

the benchmarks are from the linked commit

change `_events` to be without `proto: null`

Commit: eb29e97

I think the performance without proto is not fully representative as the event name can be anything so the dictionary mode is not used here

Benchmark URL

12:55:39 ++ Rscript benchmark/compare.R
12:55:40 confidence improvement accuracy (*) (**) (***)
12:55:40 events/ee-add-remove.js n=1000000 removeListener=0 newListener=0 ** -2.22 % ±1.50% ±2.00% ±2.60%
12:55:40 events/ee-add-remove.js n=1000000 removeListener=0 newListener=1 *** 30.34 % ±1.75% ±2.33% ±3.04%
12:55:40 events/ee-add-remove.js n=1000000 removeListener=1 newListener=0 *** 22.74 % ±1.17% ±1.56% ±2.03%
12:55:40 events/ee-add-remove.js n=1000000 removeListener=1 newListener=1 *** 10.04 % ±1.11% ±1.47% ±1.92%
12:55:40 events/ee-emit.js listeners=1 argc=0 n=2000000 *** 159.54 % ±8.72% ±11.64% ±15.20%
12:55:40 events/ee-emit.js listeners=1 argc=10 n=2000000 *** 139.14 % ±12.44% ±16.59% ±21.66%
12:55:40 events/ee-emit.js listeners=1 argc=2 n=2000000 *** 159.56 % ±13.83% ±18.46% ±24.15%
12:55:40 events/ee-emit.js listeners=1 argc=4 n=2000000 *** 148.52 % ±10.04% ±13.37% ±17.43%
12:55:40 events/ee-emit.js listeners=10 argc=0 n=2000000 *** 13.34 % ±7.48% ±9.96% ±12.96%
12:55:40 events/ee-emit.js listeners=10 argc=10 n=2000000 *** 11.22 % ±5.66% ±7.53% ±9.81%
12:55:40 events/ee-emit.js listeners=10 argc=2 n=2000000 3.11 % ±6.21% ±8.27% ±10.77%
12:55:40 events/ee-emit.js listeners=10 argc=4 n=2000000 *** 12.07 % ±6.04% ±8.04% ±10.47%
12:55:40 events/ee-emit.js listeners=5 argc=0 n=2000000 *** 20.76 % ±9.34% ±12.44% ±16.24%
12:55:40 events/ee-emit.js listeners=5 argc=10 n=2000000 *** 17.29 % ±8.71% ±11.59% ±15.10%
12:55:40 events/ee-emit.js listeners=5 argc=2 n=2000000 * 13.10 % ±9.93% ±13.21% ±17.20%
12:55:40 events/ee-emit.js listeners=5 argc=4 n=2000000 * 9.82 % ±9.51% ±12.66% ±16.48%
12:55:40 events/ee-listen-unique.js n=1000000 events=1 0.24 % ±1.32% ±1.76% ±2.29%
12:55:40 events/ee-listen-unique.js n=1000000 events=10 *** -3.02 % ±1.08% ±1.44% ±1.88%
12:55:40 events/ee-listen-unique.js n=1000000 events=2 *** -2.28 % ±0.69% ±0.92% ±1.20%
12:55:40 events/ee-listen-unique.js n=1000000 events=20 ** -2.16 % ±1.56% ±2.09% ±2.73%
12:55:40 events/ee-listen-unique.js n=1000000 events=3 *** -2.03 % ±0.98% ±1.31% ±1.71%
12:55:40 events/ee-listen-unique.js n=1000000 events=5 *** -4.36 % ±0.89% ±1.19% ±1.55%
12:55:40 events/ee-listener-count-on-prototype.js n=50000000 *** -6.40 % ±3.40% ±4.53% ±5.91%
12:55:40 events/ee-listeners.js raw='false' listeners=5 n=5000000 * -8.30 % ±6.34% ±8.45% ±11.02%
12:55:40 events/ee-listeners.js raw='false' listeners=50 n=5000000 -1.08 % ±1.71% ±2.28% ±2.97%
12:55:40 events/ee-listeners.js raw='true' listeners=5 n=5000000 -3.00 % ±5.69% ±7.58% ±9.89%
12:55:40 events/ee-listeners.js raw='true' listeners=50 n=5000000 3.68 % ±4.65% ±6.18% ±8.05%
12:55:40 events/ee-once.js argc=0 n=20000000 -0.21 % ±0.64% ±0.85% ±1.10%
12:55:40 events/ee-once.js argc=1 n=20000000 0.06 % ±0.44% ±0.59% ±0.76%
12:55:40 events/ee-once.js argc=4 n=20000000 -0.13 % ±0.62% ±0.83% ±1.08%
12:55:40 events/ee-once.js argc=5 n=20000000 0.26 % ±0.69% ±0.91% ±1.19%
12:55:40 events/eventtarget-add-remove.js nListener=10 n=1000000 ** 0.71 % ±0.42% ±0.56% ±0.73%
12:55:40 events/eventtarget-add-remove.js nListener=5 n=1000000 0.30 % ±0.70% ±0.94% ±1.22%
12:55:40 events/eventtarget-creation.js n=1000000 1.95 % ±3.80% ±5.09% ±6.72%
12:55:40 events/eventtarget.js listeners=1 n=1000000 -0.66 % ±5.51% ±7.34% ±9.55%
12:55:40 events/eventtarget.js listeners=10 n=1000000 -0.32 % ±3.15% ±4.19% ±5.46%
12:55:40 events/eventtarget.js listeners=5 n=1000000 -0.39 % ±5.18% ±6.90% ±8.98%
12:55:40 12:55:40 Be aware that when doing many comparisons the risk of a false-positive
12:55:40 result increases. In this case, there are 37 comparisons, you can thus
12:55:40 expect the following amount of false-positive results:
12:55:40 1.85 false positives, when considering a 5% risk acceptance (*, **, ***),
12:55:40 0.37 false positives, when considering a 1% risk acceptance (**, ***),
12:55:40 0.04 false positives, when considering a 0.1% risk acceptance (***)

ronag · 2023-10-27T14:19:11Z

change _events to be without proto: null

Looks great to me!

ronag · 2023-10-27T14:20:24Z

Also what about something like the following for streams?

diff --git a/lib/internal/streams/duplex.js b/lib/internal/streams/duplex.js
index 834d875be6..2b3fe64df9 100644
--- a/lib/internal/streams/duplex.js
+++ b/lib/internal/streams/duplex.js
@@ -63,6 +63,21 @@ function Duplex(options) {
if (!(this instanceof Duplex))
return new Duplex(options);
+ this._events = {
+ close: undefined,
+ error: undefined,
+ prefinish: undefined,
+ finish: undefined,
+ drain: undefined,
+ data: undefined,
+ end: undefined,
+ pause: undefined,
+ resume: undefined,
+ readable: undefined,
+ pipe: undefined,
+ unpipe: undefined,
+ };
+
this._readableState = new Readable.ReadableState(options, this, true);
this._writableState = new Writable.WritableState(options, this, true);
diff --git a/lib/internal/streams/readable.js b/lib/internal/streams/readable.js
index 80798a35dc..83f09194a6 100644
--- a/lib/internal/streams/readable.js
+++ b/lib/internal/streams/readable.js
@@ -316,6 +316,18 @@ function Readable(options) {
if (!(this instanceof Readable))
return new Readable(options);
+ this._events = {
+ close: undefined,
+ error: undefined,
+ data: undefined,
+ end: undefined,
+ pause: undefined,
+ resume: undefined,
+ readable: undefined,
+ pipe: undefined,
+ unpipe: undefined,
+ };
+
this._readableState = new ReadableState(options, this, false);
if (options) {
diff --git a/lib/internal/streams/writable.js b/lib/internal/streams/writable.js
index 74573033ea..69fb2be7f0 100644
--- a/lib/internal/streams/writable.js
+++ b/lib/internal/streams/writable.js
@@ -382,6 +382,14 @@ function Writable(options) {
if (!(this instanceof Writable))
return new Writable(options);
+ this._events = {
+ close: undefined,
+ error: undefined,
+ prefinish: undefined,
+ finish: undefined,
+ drain: undefined,
+ };
+
this._writableState = new WritableState(options, this, false);
if (options) {

rluvaton · 2023-10-27T14:20:33Z

Do you think it's representative, I think the reason someone put __proto__ null was to be in dict mode

rluvaton · 2023-10-27T14:21:26Z

Also what about something like the following for streams?

diff --git a/lib/internal/streams/duplex.js b/lib/internal/streams/duplex.js
index 834d875be6..2b3fe64df9 100644
--- a/lib/internal/streams/duplex.js
+++ b/lib/internal/streams/duplex.js
@@ -63,6 +63,21 @@ function Duplex(options) {
if (!(this instanceof Duplex))
return new Duplex(options);
+ this._events = {
+ close: undefined,
+ error: undefined,
+ prefinish: undefined,
+ finish: undefined,
+ drain: undefined,
+ data: undefined,
+ end: undefined,
+ pause: undefined,
+ resume: undefined,
+ readable: undefined,
+ pipe: undefined,
+ unpipe: undefined,
+ };
+
this._readableState = new Readable.ReadableState(options, this, true);
this._writableState = new Writable.WritableState(options, this, true);
diff --git a/lib/internal/streams/readable.js b/lib/internal/streams/readable.js
index 80798a35dc..83f09194a6 100644
--- a/lib/internal/streams/readable.js
+++ b/lib/internal/streams/readable.js
@@ -316,6 +316,18 @@ function Readable(options) {
if (!(this instanceof Readable))
return new Readable(options);
+ this._events = {
+ close: undefined,
+ error: undefined,
+ data: undefined,
+ end: undefined,
+ pause: undefined,
+ resume: undefined,
+ readable: undefined,
+ pipe: undefined,
+ unpipe: undefined,
+ };
+
this._readableState = new ReadableState(options, this, false);
if (options) {
diff --git a/lib/internal/streams/writable.js b/lib/internal/streams/writable.js
index 74573033ea..69fb2be7f0 100644
--- a/lib/internal/streams/writable.js
+++ b/lib/internal/streams/writable.js
@@ -382,6 +382,14 @@ function Writable(options) {
if (!(this instanceof Writable))
return new Writable(options);
+ this._events = {
+ close: undefined,
+ error: undefined,
+ prefinish: undefined,
+ finish: undefined,
+ drain: undefined,
+ };
+
this._writableState = new WritableState(options, this, false);
if (options) {

I thought about that, but since I changed to Map I did not do it

benjamingr · 2023-10-27T14:51:30Z

Eh, this makes one use case slower and another one faster (changing to no proto: null), making "EventEmitter events shape specific to common use cases for streams" could be worth it, with benchmarks

lpinca · 2023-10-27T14:54:23Z

Possible duplicate of #44627 and #39939. See also #11930.

rluvaton · 2023-10-29T10:21:47Z

Supersede by #50428

events: improve creation performance
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nodejs-github-bot added events Issues and PRs related to the events subsystem / EventEmitter. needs-ci PRs that need a full CI run. labels Oct 27, 2023

rluvaton changed the title ~~events: improve creation performance~~events: improve events performanceOct 27, 2023

rluvaton force-pushed the improve-ee-creation branch from 4c02bdb to bb44f6fCompare October 27, 2023 10:11

rluvaton added the performance Issues and PRs related to the performance of Node.js. label Oct 27, 2023

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events: replace _events with Map
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events: remove __proto__ null from _events
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rluvaton closed this Oct 29, 2023

rluvaton deleted the improve-ee-creation branch October 29, 2023 10:21

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rluvaton commented Oct 27, 2023• edited Loading Uh oh! There was an error while loading. Please reload this page.

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Benchmarks

Change _events to be a Map:

Change to Map todos:

change _events to be without __proto__: null

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change _events to be without __proto__: null

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rluvaton commented Oct 27, 2023•
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Change `_events` to be a `Map`:

Change to `Map` todos:

change `_events` to be without `proto: null`

ronag commented Oct 27, 2023•
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rluvaton commented Oct 27, 2023•
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rluvaton commented Oct 27, 2023•
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change `_events` to be without `proto: null`