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Merged
byrnedj merged 1 commit into from
Mar 23, 2023
Merged

Per tier pool stats #70

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9 changes: 5 additions & 4 deletions cachelib/allocator/Cache.cpp
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Original file line numberDiff line numberDiff line change
Expand Up@@ -235,17 +235,18 @@ void CacheBase::updateGlobalCacheStats(const std::string& statPrefix) const {
statPrefix + "cache.size.configured",
memStats.configuredRamCacheSize + memStats.nvmCacheSize);

//TODO: add specific per-tier counters
const auto stats = getGlobalCacheStats();
counters_.updateDelta(statPrefix + "cache.alloc_attempts",
stats.allocAttempts);
std::accumulate(stats.allocAttempts.begin(), stats.allocAttempts.end(),0));
counters_.updateDelta(statPrefix + "cache.eviction_attempts",
stats.evictionAttempts);
std::accumulate(stats.evictionAttempts.begin(),stats.evictionAttempts.end(),0));
counters_.updateDelta(statPrefix + "cache.alloc_failures",
stats.allocFailures);
std::accumulate(stats.allocFailures.begin(),stats.allocFailures.end(),0));
counters_.updateDelta(statPrefix + "cache.invalid_allocs",
stats.invalidAllocs);
const std::string ramEvictionKey = statPrefix + "ram.evictions";
counters_.updateDelta(ramEvictionKey, stats.numEvictions);
counters_.updateDelta(ramEvictionKey, std::accumulate(stats.numEvictions.begin(),stats.numEvictions.end(),0));
// get the new delta to see if uploading any eviction age stats or lifetime
// stats makes sense.
uint64_t ramEvictionDelta = counters_.getDelta(ramEvictionKey);
Expand Down
156 changes: 122 additions & 34 deletions cachelib/allocator/CacheAllocator-inl.h
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Original file line numberDiff line numberDiff line change
Expand Up@@ -418,8 +418,7 @@ CacheAllocator<CacheTrait>::allocateInternalTier(TierId tid,
util::RollingLatencyTracker rollTracker{
(*stats_.classAllocLatency)[tid][pid][cid]};

// TODO: per-tier
(*stats_.allocAttempts)[pid][cid].inc();
(*stats_.allocAttempts)[tid][pid][cid].inc();

void* memory = allocator_[tid]->allocate(pid, requiredSize);

Expand All@@ -445,12 +444,12 @@ CacheAllocator<CacheTrait>::allocateInternalTier(TierId tid,
handle = acquire(new (memory) Item(key, size, creationTime, expiryTime));
if (handle) {
handle.markNascent();
(*stats_.fragmentationSize)[pid][cid].add(
(*stats_.fragmentationSize)[tid][pid][cid].add(
util::getFragmentation(*this, *handle));
}

} else { // failed to allocate memory.
(*stats_.allocFailures)[pid][cid].inc(); // TODO: per-tier
(*stats_.allocFailures)[tid][pid][cid].inc();
// wake up rebalancer
if (poolRebalancer_) {
poolRebalancer_->wakeUp();
Expand DownExpand Up@@ -522,16 +521,14 @@ CacheAllocator<CacheTrait>::allocateChainedItemInternal(
util::RollingLatencyTracker rollTracker{
(*stats_.classAllocLatency)[tid][pid][cid]};

// TODO: per-tier? Right now stats_ are not used in any public periodic
// worker
(*stats_.allocAttempts)[pid][cid].inc();
(*stats_.allocAttempts)[tid][pid][cid].inc();

void* memory = allocator_[tid]->allocate(pid, requiredSize);
if (memory == nullptr) {
memory = findEviction(tid, pid, cid);
}
if (memory == nullptr) {
(*stats_.allocFailures)[pid][cid].inc();
(*stats_.allocFailures)[tid][pid][cid].inc();
return WriteHandle{};
}

Expand All@@ -543,7 +540,7 @@ CacheAllocator<CacheTrait>::allocateChainedItemInternal(

if (child) {
child.markNascent();
(*stats_.fragmentationSize)[pid][cid].add(
(*stats_.fragmentationSize)[tid][pid][cid].add(
util::getFragmentation(*this, *child));
}

Expand DownExpand Up@@ -858,7 +855,7 @@ CacheAllocator<CacheTrait>::releaseBackToAllocator(Item& it,
stats_.perPoolEvictionAgeSecs_[allocInfo.poolId].trackValue(refreshTime);
}

(*stats_.fragmentationSize)[allocInfo.poolId][allocInfo.classId].sub(
(*stats_.fragmentationSize)[tid][allocInfo.poolId][allocInfo.classId].sub(
util::getFragmentation(*this, it));

// Chained items can only end up in this place if the user has allocated
Expand DownExpand Up@@ -941,7 +938,7 @@ CacheAllocator<CacheTrait>::releaseBackToAllocator(Item& it,

const auto childInfo =
allocator_[tid]->getAllocInfo(static_cast<const void*>(head));
(*stats_.fragmentationSize)[childInfo.poolId][childInfo.classId].sub(
(*stats_.fragmentationSize)[tid][childInfo.poolId][childInfo.classId].sub(
util::getFragmentation(*this, *head));

removeFromMMContainer(*head);
Expand DownExpand Up@@ -1585,20 +1582,20 @@ CacheAllocator<CacheTrait>::findEviction(TierId tid, PoolId pid, ClassId cid) {
Item* candidate = nullptr;
typename NvmCacheT::PutToken token;

mmContainer.withEvictionIterator([this, pid, cid, &candidate, &toRecycle,
mmContainer.withEvictionIterator([this, tid, pid, cid, &candidate, &toRecycle,
&searchTries, &mmContainer, &lastTier,
&token](auto&& itr) {
if (!itr) {
++searchTries;
(*stats_.evictionAttempts)[pid][cid].inc();
(*stats_.evictionAttempts)[tid][pid][cid].inc();
return;
}

while ((config_.evictionSearchTries == 0 ||
config_.evictionSearchTries > searchTries) &&
itr) {
++searchTries;
(*stats_.evictionAttempts)[pid][cid].inc();
(*stats_.evictionAttempts)[tid][pid][cid].inc();

auto* toRecycle_ = itr.get();
auto* candidate_ =
Expand DownExpand Up@@ -1698,6 +1695,7 @@ CacheAllocator<CacheTrait>::findEviction(TierId tid, PoolId pid, ClassId cid) {
XDCHECK(!candidate->isAccessible());
XDCHECK(candidate->getKey() == evictedToNext->getKey());

(*stats_.numWritebacks)[tid][pid][cid].inc();
wakeUpWaiters(*candidate, std::move(evictedToNext));
}

Expand All@@ -1707,9 +1705,9 @@ CacheAllocator<CacheTrait>::findEviction(TierId tid, PoolId pid, ClassId cid) {
// NULL. If `ref` == 0 then it means that we are the last holder of
// that item.
if (candidate->hasChainedItem()) {
(*stats_.chainedItemEvictions)[pid][cid].inc();
(*stats_.chainedItemEvictions)[tid][pid][cid].inc();
} else {
(*stats_.regularItemEvictions)[pid][cid].inc();
(*stats_.regularItemEvictions)[tid][pid][cid].inc();
}

if (auto eventTracker = getEventTracker()) {
Expand DownExpand Up@@ -2304,7 +2302,7 @@ bool CacheAllocator<CacheTrait>::recordAccessInMMContainer(Item& item,
const auto tid = getTierId(item);
const auto allocInfo =
allocator_[tid]->getAllocInfo(static_cast<const void*>(&item));
(*stats_.cacheHits)[allocInfo.poolId][allocInfo.classId].inc();
(*stats_.cacheHits)[tid][allocInfo.poolId][allocInfo.classId].inc();

// track recently accessed items if needed
if (UNLIKELY(config_.trackRecentItemsForDump)) {
Expand DownExpand Up@@ -2773,6 +2771,8 @@ size_t CacheAllocator<CacheTrait>::getPoolSize(PoolId poolId) const {

template <typename CacheTrait>
PoolStats CacheAllocator<CacheTrait>::getPoolStats(PoolId poolId) const {
//this pool ref is just used to get class ids, which will be the
//same across tiers
const auto& pool = allocator_[currentTier()]->getPool(poolId);
const auto& allocSizes = pool.getAllocSizes();
auto mpStats = pool.getStats();
Expand All@@ -2791,24 +2791,42 @@ PoolStats CacheAllocator<CacheTrait>::getPoolStats(PoolId poolId) const {
// TODO export evictions, numItems etc from compact cache directly.
if (!isCompactCache) {
for (const ClassId cid : classIds) {
uint64_t classHits = (*stats_.cacheHits)[poolId][cid].get();
XDCHECK(mmContainers_[currentTier()][poolId][cid],
folly::sformat("Pid {}, Cid {} not initialized.", poolId, cid));
uint64_t allocAttempts, evictionAttempts, allocFailures,
fragmentationSize, classHits, chainedItemEvictions,
regularItemEvictions, numWritebacks = 0;
MMContainerStat mmContainerStats;
for (TierId tid = 0; tid < getNumTiers(); tid++) {
allocAttempts += (*stats_.allocAttempts)[tid][poolId][cid].get();
evictionAttempts += (*stats_.evictionAttempts)[tid][poolId][cid].get();
allocFailures += (*stats_.allocFailures)[tid][poolId][cid].get();
fragmentationSize += (*stats_.fragmentationSize)[tid][poolId][cid].get();
classHits += (*stats_.cacheHits)[tid][poolId][cid].get();
chainedItemEvictions += (*stats_.chainedItemEvictions)[tid][poolId][cid].get();
regularItemEvictions += (*stats_.regularItemEvictions)[tid][poolId][cid].get();
numWritebacks += (*stats_.numWritebacks)[tid][poolId][cid].get();
mmContainerStats += getMMContainerStat(tid, poolId, cid);
XDCHECK(mmContainers_[tid][poolId][cid],
folly::sformat("Tid {}, Pid {}, Cid {} not initialized.", tid, poolId, cid));
}
cacheStats.insert(
{cid,
{allocSizes[cid], (*stats_.allocAttempts)[poolId][cid].get(),
(*stats_.evictionAttempts)[poolId][cid].get(),
(*stats_.allocFailures)[poolId][cid].get(),
(*stats_.fragmentationSize)[poolId][cid].get(), classHits,
(*stats_.chainedItemEvictions)[poolId][cid].get(),
(*stats_.regularItemEvictions)[poolId][cid].get(),
getMMContainerStat(currentTier(), poolId, cid)}});
{allocSizes[cid],
allocAttempts,
evictionAttempts,
allocFailures,
fragmentationSize,
classHits,
chainedItemEvictions,
regularItemEvictions,
numWritebacks,
mmContainerStats}});
totalHits += classHits;
}
}

PoolStats ret;
ret.isCompactCache = isCompactCache;
//pool name is also shared among tiers
ret.poolName = allocator_[currentTier()]->getPoolName(poolId);
ret.poolSize = pool.getPoolSize();
ret.poolUsableSize = pool.getPoolUsableSize();
Expand All@@ -2821,6 +2839,59 @@ PoolStats CacheAllocator<CacheTrait>::getPoolStats(PoolId poolId) const {
return ret;
}

template <typename CacheTrait>
PoolStats CacheAllocator<CacheTrait>::getPoolStats(TierId tid, PoolId poolId) const {
const auto& pool = allocator_[tid]->getPool(poolId);
const auto& allocSizes = pool.getAllocSizes();
auto mpStats = pool.getStats();
const auto& classIds = mpStats.classIds;

// check if this is a compact cache.
bool isCompactCache = false;
{
folly::SharedMutex::ReadHolder lock(compactCachePoolsLock_);
isCompactCache = isCompactCachePool_[poolId];
}

std::unordered_map<ClassId, CacheStat> cacheStats;
uint64_t totalHits = 0;
// cacheStats is only menaningful for pools that are not compact caches.
// TODO export evictions, numItems etc from compact cache directly.
if (!isCompactCache) {
for (const ClassId cid : classIds) {
uint64_t classHits = (*stats_.cacheHits)[tid][poolId][cid].get();
XDCHECK(mmContainers_[tid][poolId][cid],
folly::sformat("Tid {}, Pid {}, Cid {} not initialized.", tid, poolId, cid));
cacheStats.insert(
{cid,
{allocSizes[cid],
(*stats_.allocAttempts)[tid][poolId][cid].get(),
(*stats_.evictionAttempts)[tid][poolId][cid].get(),
(*stats_.allocFailures)[tid][poolId][cid].get(),
(*stats_.fragmentationSize)[tid][poolId][cid].get(),
classHits,
(*stats_.chainedItemEvictions)[tid][poolId][cid].get(),
(*stats_.regularItemEvictions)[tid][poolId][cid].get(),
(*stats_.numWritebacks)[tid][poolId][cid].get(),
getMMContainerStat(tid, poolId, cid)}});
totalHits += classHits;
}
}

PoolStats ret;
ret.isCompactCache = isCompactCache;
ret.poolName = allocator_[tid]->getPoolName(poolId);
ret.poolSize = pool.getPoolSize();

@vinser52vinser52Mar 17, 2023

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Do we want the size of a particular tier or the total pool size?

ret.poolUsableSize = pool.getPoolUsableSize();
ret.poolAdvisedSize = pool.getPoolAdvisedSize();
ret.cacheStats = std::move(cacheStats);
ret.mpStats = std::move(mpStats);
ret.numPoolGetHits = totalHits;
ret.evictionAgeSecs = stats_.perPoolEvictionAgeSecs_[poolId].estimate();

return ret;
}

template <typename CacheTrait>
ACStats CacheAllocator<CacheTrait>::getACStats(TierId tid,
PoolId poolId,
Expand DownExpand Up@@ -3072,7 +3143,7 @@ bool CacheAllocator<CacheTrait>::moveForSlabRelease(
const auto allocInfo = allocator_[tid]->getAllocInfo(oldItem.getMemory());
allocator_[tid]->free(&oldItem);

(*stats_.fragmentationSize)[allocInfo.poolId][allocInfo.classId].sub(
(*stats_.fragmentationSize)[tid][allocInfo.poolId][allocInfo.classId].sub(
util::getFragmentation(*this, oldItem));
stats_.numMoveSuccesses.inc();
return true;
Expand DownExpand Up@@ -3351,12 +3422,13 @@ void CacheAllocator<CacheTrait>::evictForSlabRelease(
nvmCache_->put(*evicted, std::move(token));
}

const auto tid = getTierId(*evicted);
const auto allocInfo =
allocator_[getTierId(*evicted)]->getAllocInfo(static_cast<const void*>(evicted));
allocator_[tid]->getAllocInfo(static_cast<const void*>(evicted));
if (evicted->hasChainedItem()) {
(*stats_.chainedItemEvictions)[allocInfo.poolId][allocInfo.classId].inc();
(*stats_.chainedItemEvictions)[tid][allocInfo.poolId][allocInfo.classId].inc();
} else {
(*stats_.regularItemEvictions)[allocInfo.poolId][allocInfo.classId].inc();
(*stats_.regularItemEvictions)[tid][allocInfo.poolId][allocInfo.classId].inc();
}

stats_.numEvictionSuccesses.inc();
Expand DownExpand Up@@ -3579,8 +3651,13 @@ folly::IOBufQueue CacheAllocator<CacheTrait>::saveStateToIOBuf() {
for (PoolId pid : pools) {
for (unsigned int cid = 0; cid < (*stats_.fragmentationSize)[pid].size();
++cid) {
uint64_t fragmentationSize = 0;
for (TierId tid = 0; tid < getNumTiers(); tid++) {
fragmentationSize += (*stats_.fragmentationSize)[tid][pid][cid].get();
}
Comment on lines +3654 to +3657

@vinser52vinser52Mar 17, 2023

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Minor: Would it be better to use std::accumulate as above in Cache.cpp?

metadata_.fragmentationSize()[pid][static_cast<ClassId>(cid)] =
(*stats_.fragmentationSize)[pid][cid].get();
fragmentationSize;

}
if (isCompactCachePool_[pid]) {
metadata_.compactCachePools()->push_back(pid);
Expand DownExpand Up@@ -3826,8 +3903,19 @@ void CacheAllocator<CacheTrait>::initStats() {
// deserialize the fragmentation size of each thread.
for (const auto& pid : *metadata_.fragmentationSize()) {
for (const auto& cid : pid.second) {
(*stats_.fragmentationSize)[pid.first][cid.first].set(
static_cast<uint64_t>(cid.second));
//in multi-tier we serialized as the sum - no way
//to get back so just divide the two for now
//TODO: proper multi-tier serialization
uint64_t total = static_cast<uint64_t>(cid.second);
uint64_t part = total / getNumTiers();
uint64_t sum = 0;
for (TierId tid = 1; tid < getNumTiers(); tid++) {
(*stats_.fragmentationSize)[tid][pid.first][cid.first].set(part);
sum += part;
}
uint64_t leftover = total - sum;
(*stats_.fragmentationSize)[0][pid.first][cid.first].set(leftover);

}
}

Expand Down
6 changes: 4 additions & 2 deletions cachelib/allocator/CacheAllocator.h
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Original file line numberDiff line numberDiff line change
Expand Up@@ -1233,6 +1233,8 @@ class CacheAllocator : public CacheBase {

// pool stats by pool id
PoolStats getPoolStats(PoolId pid) const override final;
// pool stats by tier id and pool id
PoolStats getPoolStats(TierId tid, PoolId pid) const;

// This can be expensive so it is not part of PoolStats
PoolEvictionAgeStats getPoolEvictionAgeStats(
Expand DownExpand Up@@ -2015,9 +2017,9 @@ auto& mmContainer = getMMContainer(tid, pid, cid);
XDCHECK(!candidate->isMarkedForEviction() && !candidate->isMoving());

if (candidate->hasChainedItem()) {
(*stats_.chainedItemEvictions)[pid][cid].inc();
(*stats_.chainedItemEvictions)[tid][pid][cid].inc();
} else {
(*stats_.regularItemEvictions)[pid][cid].inc();
(*stats_.regularItemEvictions)[tid][pid][cid].inc();
}

// it's safe to recycle the item here as there are no more
Expand Down
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