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Introduce CPU timers for iterator seek and next (#5076)

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Summary:
Introduce CPU timers for iterator seek and next operations. Seek
counter includes SeekToFirst, SeekToLast and SeekForPrev, w/ the
caveat that SeekToLast timer doesn't include some post processing
time if upper bound is defined.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5076

Differential Revision: D14525218

Pulled By: fredfsh

fbshipit-source-id: 03ba25df3b22b06c072621e4de0eacfa1445f0d9
This commit is contained in:
Shi Feng 2019-03-26 16:20:52 -07:00 committed by Facebook Github Bot
parent 4774a9409b
commit 01e6badbb6
5 changed files with 236 additions and 1 deletions
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7
db/db_iter.cc
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@ -374,6 +374,7 @@ void DBIter::Next() {
assert(valid_);
assert(status_.ok());
PERF_CPU_TIMER_GUARD(iter_next_cpu_nanos, env_);
// Release temporarily pinned blocks from last operation
ReleaseTempPinnedData();
ResetInternalKeysSkippedCounter();
@ -731,6 +732,8 @@ bool DBIter::MergeValuesNewToOld() {
void DBIter::Prev() {
assert(valid_);
assert(status_.ok());
PERF_CPU_TIMER_GUARD(iter_prev_cpu_nanos, env_);
ReleaseTempPinnedData();
ResetInternalKeysSkippedCounter();
bool ok = true;
@ -1261,6 +1264,7 @@ SequenceNumber DBIter::MaxVisibleSequenceNumber() {
}
void DBIter::Seek(const Slice& target) {
PERF_CPU_TIMER_GUARD(iter_seek_cpu_nanos, env_);
StopWatch sw(env_, statistics_, DB_SEEK);
status_ = Status::OK();
ReleaseTempPinnedData();
@ -1318,6 +1322,7 @@ void DBIter::Seek(const Slice& target) {
}
void DBIter::SeekForPrev(const Slice& target) {
PERF_CPU_TIMER_GUARD(iter_seek_cpu_nanos, env_);
StopWatch sw(env_, statistics_, DB_SEEK);
status_ = Status::OK();
ReleaseTempPinnedData();
@ -1378,6 +1383,7 @@ void DBIter::SeekToFirst() {
Seek(*iterate_lower_bound_);
return;
}
PERF_CPU_TIMER_GUARD(iter_seek_cpu_nanos, env_);
// Don't use iter_::Seek() if we set a prefix extractor
// because prefix seek will be used.
if (prefix_extractor_ != nullptr && !total_order_seek_) {
@ -1429,6 +1435,7 @@ void DBIter::SeekToLast() {
return;
}
PERF_CPU_TIMER_GUARD(iter_seek_cpu_nanos, env_);
// Don't use iter_::Seek() if we set a prefix extractor
// because prefix seek will be used.
if (prefix_extractor_ != nullptr && !total_order_seek_) {

87
db/db_test2.cc
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@ -1805,7 +1805,7 @@ class MockPersistentCache : public PersistentCache {
#ifdef OS_LINUX
// Make sure that in CPU time perf context counters, Env::NowCPUNanos()
// is used, rather than Env::CPUNanos();
TEST_F(DBTest2, TestPerfContextCpuTime) {
TEST_F(DBTest2, TestPerfContextGetCpuTime) {
// force resizing table cache so table handle is not preloaded so that
// we can measure find_table_nanos during Get().
dbfull()->TEST_table_cache()->SetCapacity(0);
@ -1836,6 +1836,91 @@ TEST_F(DBTest2, TestPerfContextCpuTime) {
SetPerfLevel(PerfLevel::kDisable);
rocksdb::SyncPoint::GetInstance()->DisableProcessing();
}
TEST_F(DBTest2, TestPerfContextIterCpuTime) {
DestroyAndReopen(CurrentOptions());
// force resizing table cache so table handle is not preloaded so that
// we can measure find_table_nanos during iteration
dbfull()->TEST_table_cache()->SetCapacity(0);
const size_t kNumEntries = 10;
for (size_t i = 0; i < kNumEntries; ++i) {
ASSERT_OK(Put("k" + ToString(i), "v" + ToString(i)));
}
ASSERT_OK(Flush());
for (size_t i = 0; i < kNumEntries; ++i) {
ASSERT_EQ("v" + ToString(i), Get("k" + ToString(i)));
}
std::string last_key = "k" + ToString(kNumEntries - 1);
std::string last_value = "v" + ToString(kNumEntries - 1);
env_->now_cpu_count_.store(0);
// CPU timing is not enabled with kEnableTimeExceptForMutex
SetPerfLevel(PerfLevel::kEnableTimeExceptForMutex);
Iterator* iter = db_->NewIterator(ReadOptions());
iter->Seek("k0");
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v0", iter->value().ToString());
iter->SeekForPrev(last_key);
ASSERT_TRUE(iter->Valid());
iter->SeekToLast();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(last_value, iter->value().ToString());
iter->SeekToFirst();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v0", iter->value().ToString());
ASSERT_EQ(0, get_perf_context()->iter_seek_cpu_nanos);
iter->Next();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v1", iter->value().ToString());
ASSERT_EQ(0, get_perf_context()->iter_next_cpu_nanos);
iter->Prev();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v0", iter->value().ToString());
ASSERT_EQ(0, get_perf_context()->iter_prev_cpu_nanos);
ASSERT_EQ(0, env_->now_cpu_count_.load());
delete iter;
uint64_t kDummyAddonTime = uint64_t{1000000000000};
// Add time to NowNanos() reading.
rocksdb::SyncPoint::GetInstance()->SetCallBack(
"TableCache::FindTable:0",
[&](void* /*arg*/) { env_->addon_time_.fetch_add(kDummyAddonTime); });
rocksdb::SyncPoint::GetInstance()->EnableProcessing();
SetPerfLevel(PerfLevel::kEnableTimeAndCPUTimeExceptForMutex);
iter = db_->NewIterator(ReadOptions());
iter->Seek("k0");
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v0", iter->value().ToString());
iter->SeekForPrev(last_key);
ASSERT_TRUE(iter->Valid());
iter->SeekToLast();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(last_value, iter->value().ToString());
iter->SeekToFirst();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v0", iter->value().ToString());
ASSERT_GT(get_perf_context()->iter_seek_cpu_nanos, 0);
ASSERT_LT(get_perf_context()->iter_seek_cpu_nanos, kDummyAddonTime);
iter->Next();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v1", iter->value().ToString());
ASSERT_GT(get_perf_context()->iter_next_cpu_nanos, 0);
ASSERT_LT(get_perf_context()->iter_next_cpu_nanos, kDummyAddonTime);
iter->Prev();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v0", iter->value().ToString());
ASSERT_GT(get_perf_context()->iter_prev_cpu_nanos, 0);
ASSERT_LT(get_perf_context()->iter_prev_cpu_nanos, kDummyAddonTime);
ASSERT_GE(env_->now_cpu_count_.load(), 12);
ASSERT_GT(get_perf_context()->find_table_nanos, kDummyAddonTime);
SetPerfLevel(PerfLevel::kDisable);
rocksdb::SyncPoint::GetInstance()->DisableProcessing();
delete iter;
}
#endif // OS_LINUX
#ifndef OS_SOLARIS // GetUniqueIdFromFile is not implemented

125
db/perf_context_test.cc
View File

@ -813,6 +813,131 @@ TEST_F(PerfContextTest, PerfContextByLevelGetSet) {
ASSERT_NE(std::string::npos,
zero_excluded.find("block_cache_miss_count = 4@level1, 2@level3"));
}
TEST_F(PerfContextTest, CPUTimer) {
DestroyDB(kDbName, Options());
auto db = OpenDb();
WriteOptions write_options;
ReadOptions read_options;
SetPerfLevel(PerfLevel::kEnableTimeAndCPUTimeExceptForMutex);
std::string max_str = "0";
for (int i = 0; i < FLAGS_total_keys; ++i) {
std::string i_str = ToString(i);
std::string key = "k" + i_str;
std::string value = "v" + i_str;
max_str = max_str > i_str ? max_str : i_str;
db->Put(write_options, key, value);
}
std::string last_key = "k" + max_str;
std::string last_value = "v" + max_str;
{
// Get
get_perf_context()->Reset();
std::string value;
ASSERT_OK(db->Get(read_options, "k0", &value));
ASSERT_EQ(value, "v0");
if (FLAGS_verbose) {
std::cout << "Get CPU time nanos: "
<< get_perf_context()->get_cpu_nanos << "ns\n";
}
// Iter
std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
// Seek
get_perf_context()->Reset();
iter->Seek(last_key);
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(last_value, iter->value().ToString());
if (FLAGS_verbose) {
std::cout << "Iter Seek CPU time nanos: "
<< get_perf_context()->iter_seek_cpu_nanos << "ns\n";
}
// SeekForPrev
get_perf_context()->Reset();
iter->SeekForPrev(last_key);
ASSERT_TRUE(iter->Valid());
if (FLAGS_verbose) {
std::cout << "Iter SeekForPrev CPU time nanos: "
<< get_perf_context()->iter_seek_cpu_nanos << "ns\n";
}
// SeekToLast
get_perf_context()->Reset();
iter->SeekToLast();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(last_value, iter->value().ToString());
if (FLAGS_verbose) {
std::cout << "Iter SeekToLast CPU time nanos: "
<< get_perf_context()->iter_seek_cpu_nanos << "ns\n";
}
// SeekToFirst
get_perf_context()->Reset();
iter->SeekToFirst();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v0", iter->value().ToString());
if (FLAGS_verbose) {
std::cout << "Iter SeekToFirst CPU time nanos: "
<< get_perf_context()->iter_seek_cpu_nanos << "ns\n";
}
// Next
get_perf_context()->Reset();
iter->Next();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v1", iter->value().ToString());
if (FLAGS_verbose) {
std::cout << "Iter Next CPU time nanos: "
<< get_perf_context()->iter_next_cpu_nanos << "ns\n";
}
// Prev
get_perf_context()->Reset();
iter->Prev();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v0", iter->value().ToString());
if (FLAGS_verbose) {
std::cout << "Iter Prev CPU time nanos: "
<< get_perf_context()->iter_prev_cpu_nanos << "ns\n";
}
// monotonically increasing
get_perf_context()->Reset();
auto count = get_perf_context()->iter_seek_cpu_nanos;
for (int i = 0; i < FLAGS_total_keys; ++i) {
iter->Seek("k" + ToString(i));
ASSERT_TRUE(iter->Valid());
ASSERT_EQ("v" + ToString(i), iter->value().ToString());
auto next_count = get_perf_context()->iter_seek_cpu_nanos;
ASSERT_GT(next_count, count);
count = next_count;
}
// iterator creation/destruction; multiple iterators
{
std::unique_ptr<Iterator> iter2(db->NewIterator(read_options));
ASSERT_EQ(count, get_perf_context()->iter_seek_cpu_nanos);
iter2->Seek(last_key);
ASSERT_TRUE(iter2->Valid());
ASSERT_EQ(last_value, iter2->value().ToString());
ASSERT_GT(get_perf_context()->iter_seek_cpu_nanos, count);
count = get_perf_context()->iter_seek_cpu_nanos;
}
ASSERT_EQ(count, get_perf_context()->iter_seek_cpu_nanos);
}
}
} // namespace rocksdb
int main(int argc, char** argv) {

3
include/rocksdb/perf_context.h
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@ -218,6 +218,9 @@ struct PerfContext {
uint64_t env_new_logger_nanos;
uint64_t get_cpu_nanos;
uint64_t iter_next_cpu_nanos;
uint64_t iter_prev_cpu_nanos;
uint64_t iter_seek_cpu_nanos;
std::map<uint32_t, PerfContextByLevel>* level_to_perf_context = nullptr;
bool per_level_perf_context_enabled = false;

15
monitoring/perf_context.cc
View File

@ -118,6 +118,9 @@ PerfContext::PerfContext(const PerfContext& other) {
env_unlock_file_nanos = other.env_unlock_file_nanos;
env_new_logger_nanos = other.env_new_logger_nanos;
get_cpu_nanos = other.get_cpu_nanos;
iter_next_cpu_nanos = other.iter_next_cpu_nanos;
iter_prev_cpu_nanos = other.iter_prev_cpu_nanos;
iter_seek_cpu_nanos = other.iter_seek_cpu_nanos;
if (per_level_perf_context_enabled && level_to_perf_context != nullptr) {
ClearPerLevelPerfContext();
}
@ -210,6 +213,9 @@ PerfContext::PerfContext(PerfContext&& other) noexcept {
env_unlock_file_nanos = other.env_unlock_file_nanos;
env_new_logger_nanos = other.env_new_logger_nanos;
get_cpu_nanos = other.get_cpu_nanos;
iter_next_cpu_nanos = other.iter_next_cpu_nanos;
iter_prev_cpu_nanos = other.iter_prev_cpu_nanos;
iter_seek_cpu_nanos = other.iter_seek_cpu_nanos;
if (per_level_perf_context_enabled && level_to_perf_context != nullptr) {
ClearPerLevelPerfContext();
}
@ -304,6 +310,9 @@ PerfContext& PerfContext::operator=(const PerfContext& other) {
env_unlock_file_nanos = other.env_unlock_file_nanos;
env_new_logger_nanos = other.env_new_logger_nanos;
get_cpu_nanos = other.get_cpu_nanos;
iter_next_cpu_nanos = other.iter_next_cpu_nanos;
iter_prev_cpu_nanos = other.iter_prev_cpu_nanos;
iter_seek_cpu_nanos = other.iter_seek_cpu_nanos;
if (per_level_perf_context_enabled && level_to_perf_context != nullptr) {
ClearPerLevelPerfContext();
}
@ -395,6 +404,9 @@ void PerfContext::Reset() {
env_unlock_file_nanos = 0;
env_new_logger_nanos = 0;
get_cpu_nanos = 0;
iter_next_cpu_nanos = 0;
iter_prev_cpu_nanos = 0;
iter_seek_cpu_nanos = 0;
if (per_level_perf_context_enabled && level_to_perf_context) {
for (auto& kv : *level_to_perf_context) {
kv.second.Reset();
@ -509,6 +521,9 @@ std::string PerfContext::ToString(bool exclude_zero_counters) const {
PERF_CONTEXT_OUTPUT(env_unlock_file_nanos);
PERF_CONTEXT_OUTPUT(env_new_logger_nanos);
PERF_CONTEXT_OUTPUT(get_cpu_nanos);
PERF_CONTEXT_OUTPUT(iter_next_cpu_nanos);
PERF_CONTEXT_OUTPUT(iter_prev_cpu_nanos);
PERF_CONTEXT_OUTPUT(iter_seek_cpu_nanos);
PERF_CONTEXT_BY_LEVEL_OUTPUT_ONE_COUNTER(bloom_filter_useful);
PERF_CONTEXT_BY_LEVEL_OUTPUT_ONE_COUNTER(bloom_filter_full_positive);
PERF_CONTEXT_BY_LEVEL_OUTPUT_ONE_COUNTER(bloom_filter_full_true_positive);