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Add TopKTags class to track multiple tags on storage server

This commit is contained in:
sfc-gh-tclinkenbeard 2022-04-02 16:23:19 -07:00
parent 124527a668
commit 886594b98a
2 changed files with 65 additions and 16 deletions
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51
fdbserver/TransactionTagCounter.cpp
View File

@ -21,8 +21,39 @@
#include "fdbserver/TransactionTagCounter.h"
#include "flow/Trace.h"
void TopKTags::incrementTagCount(TransactionTag tag, int previousCount, int increase) {
auto iter = std::find_if(topTags.begin(), topTags.end(), [tag](const auto& tc) { return tc.tag == tag; });
if (iter != topTags.end()) {
ASSERT_EQ(previousCount, iter->count);
iter->count += increase;
} else if (topTags.size() < limit) {
ASSERT_EQ(previousCount, 0);
topTags.emplace_back(tag, increase);
} else {
auto toReplace = std::min_element(topTags.begin(), topTags.end());
ASSERT_GE(toReplace->count, previousCount);
if (toReplace->count < previousCount + increase) {
toReplace->tag = tag;
toReplace->count = previousCount + increase;
}
}
}
std::vector<StorageQueuingMetricsReply::TagInfo> TopKTags::getBusiestTags(double elapsed,
double totalSampleCount) const {
std::vector<StorageQueuingMetricsReply::TagInfo> result;
for (auto const& tagAndCounter : topTags) {
// FIXME: Confusing operator precedence
auto rate = tagAndCounter.count / CLIENT_KNOBS->READ_TAG_SAMPLE_RATE / elapsed;
if (rate > SERVER_KNOBS->MIN_TAG_READ_PAGES_RATE) {
result.emplace_back(tagAndCounter.tag, rate, tagAndCounter.count / totalSampleCount);
}
}
return result;
}
TransactionTagCounter::TransactionTagCounter(UID thisServerID)
: thisServerID(thisServerID),
: thisServerID(thisServerID), topTags(1), // TODO: Make this a knob
busiestReadTagEventHolder(makeReference<EventCacheHolder>(thisServerID.toString() + "/BusiestReadTag")) {}
void TransactionTagCounter::addRequest(Optional<TagSet> const& tags, int64_t bytes) {
@ -31,11 +62,8 @@ void TransactionTagCounter::addRequest(Optional<TagSet> const& tags, int64_t byt
double cost = costFunction(bytes);
for (auto& tag : tags.get()) {
int64_t& count = intervalCounts[TransactionTag(tag, tags.get().getArena())];
topTags.incrementTagCount(tag, count, cost);
count += cost;
if (count > busiestTagCount) {
busiestTagCount = count;
busiestTag = tag;
}
}
intervalTotalSampledCount += cost;
@ -46,22 +74,19 @@ void TransactionTagCounter::startNewInterval() {
double elapsed = now() - intervalStart;
previousBusiestTags.clear();
if (intervalStart > 0 && CLIENT_KNOBS->READ_TAG_SAMPLE_RATE > 0 && elapsed > 0) {
double rate = busiestTagCount / CLIENT_KNOBS->READ_TAG_SAMPLE_RATE / elapsed;
if (rate > SERVER_KNOBS->MIN_TAG_READ_PAGES_RATE) {
previousBusiestTags.emplace_back(busiestTag, rate, (double)busiestTagCount / intervalTotalSampledCount);
}
previousBusiestTags = topTags.getBusiestTags(elapsed, intervalTotalSampledCount);
TraceEvent("BusiestReadTag", thisServerID)
.detail("Elapsed", elapsed)
.detail("Tag", printable(busiestTag))
.detail("TagCost", busiestTagCount)
//.detail("Tag", printable(busiestTag))
//.detail("TagCost", busiestTagCount)
.detail("TotalSampledCost", intervalTotalSampledCount)
.detail("Reported", !previousBusiestTags.empty())
.detail("Reported", previousBusiestTags.size())
.trackLatest(busiestReadTagEventHolder->trackingKey);
}
intervalCounts.clear();
intervalTotalSampledCount = 0;
busiestTagCount = 0;
topTags.clear();
intervalStart = now();
}

30
fdbserver/TransactionTagCounter.h
View File

@ -24,15 +24,39 @@
#include "fdbclient/TagThrottle.actor.h"
#include "fdbserver/Knobs.h"
class TopKTags {
public:
struct TagAndCount {
TransactionTag tag;
int64_t count;
bool operator<(TagAndCount const& other) const { return count < other.count; }
explicit TagAndCount(TransactionTag tag, int64_t count) : tag(tag), count(count) {}
};
private:
// Because the number of tracked is expected to be small, they can be tracked
// in a simple vector. If the number of tracked tags increases, a more sophisticated
// data structure will be required.
std::vector<TagAndCount> topTags;
int limit;
public:
explicit TopKTags(int limit) : limit(limit) { ASSERT_GT(limit, 0); }
void incrementTagCount(TransactionTag tag, int previousCount, int increase);
std::vector<StorageQueuingMetricsReply::TagInfo> getBusiestTags(double elapsed, double totalSampleCount) const;
void clear() { topTags.clear(); }
};
class TransactionTagCounter {
UID thisServerID;
TransactionTagMap<int64_t> intervalCounts;
int64_t intervalTotalSampledCount = 0;
TransactionTag busiestTag;
int64_t busiestTagCount = 0;
TopKTags topTags;
double intervalStart = 0;
std::vector<StorageQueuingMetricsReply::TagInfo> previousBusiestTags;
UID thisServerID;
Reference<EventCacheHolder> busiestReadTagEventHolder;
public: