Optimize db_stress setup phase (#9475)

Summary:
It is too slow that our `db_crashtest.py` often kills `db_stress` before
the setup phase completes. Profiled it and found a few ways to optimize.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9475

Test Plan:
Measured setup phase time reduced 22% (36 -> 28 seconds) for first run, and
36% (38 -> 24 seconds) for non-first run on empty-ish DB.

- first run benchmark command: `rm -rf /dev/shm/dbstress*/ && mkdir -p /dev/shm/dbstress_expected/ && ./db_stress -max_key=100000000 -destroy_db_initially=1 -expected_values_dir=/dev/shm/dbstress_expected/ -db=/dev/shm/dbstress/ --clear_column_family_one_in=0 --reopen=0 --nooverwritepercent=1`

output before this PR:

```
2022/01/31-11:14:05  Initializing db_stress
...
2022/01/31-11:14:41  Starting database operations
```

output after this PR:

```
...
2022/01/31-11:12:23  Initializing db_stress
...
2022/01/31-11:12:51  Starting database operations
```

- non-first run benchmark command: `./db_stress -max_key=100000000 -destroy_db_initially=0 -expected_values_dir=/dev/shm/dbstress_expected/ -db=/dev/shm/dbstress/ --clear_column_family_one_in=0 --reopen=0 --nooverwritepercent=1`

output before this PR:

```
2022/01/31-11:20:45  Initializing db_stress
...
2022/01/31-11:21:23  Starting database operations
```

output after this PR:

```
2022/01/31-11:22:02  Initializing db_stress
...
2022/01/31-11:22:26  Starting database operations
```

- ran minified crash test a while: `DEBUG_LEVEL=0 TEST_TMPDIR=/dev/shm python3 tools/db_crashtest.py blackbox --simple --interval=10 --max_key=1000000 --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --value_size_mult=33`

Reviewed By: anand1976

Differential Revision: D33897793

Pulled By: ajkr

fbshipit-source-id: 0d7b2c93e1e2a9f8a878e87632c2455406313087
main
Andrew Kryczka 3 years ago committed by Facebook GitHub Bot
parent a495448eea
commit ed75dddc35
  1. 38
      db_stress_tool/db_stress_common.h
  2. 19
      db_stress_tool/db_stress_shared_state.h
  3. 3
      db_stress_tool/expected_state.cc

@ -407,17 +407,15 @@ inline bool GetNextPrefix(const ROCKSDB_NAMESPACE::Slice& src, std::string* v) {
#pragma warning(pop)
#endif
// convert long to a big-endian slice key
extern inline std::string GetStringFromInt(int64_t val) {
std::string little_endian_key;
std::string big_endian_key;
PutFixed64(&little_endian_key, val);
assert(little_endian_key.size() == sizeof(val));
big_endian_key.resize(sizeof(val));
for (size_t i = 0; i < sizeof(val); ++i) {
big_endian_key[i] = little_endian_key[sizeof(val) - 1 - i];
// Append `val` to `*key` in fixed-width big-endian format
extern inline void AppendIntToString(uint64_t val, std::string* key) {
// PutFixed64 uses little endian
PutFixed64(key, val);
// Reverse to get big endian
char* int_data = &((*key)[key->size() - sizeof(uint64_t)]);
for (size_t i = 0; i < sizeof(uint64_t) / 2; ++i) {
std::swap(int_data[i], int_data[sizeof(uint64_t) - 1 - i]);
}
return big_endian_key;
}
// A struct for maintaining the parameters for generating variable length keys
@ -443,13 +441,22 @@ extern inline std::string Key(int64_t val) {
uint64_t window = key_gen_ctx.window;
size_t levels = key_gen_ctx.weights.size();
std::string key;
// Over-reserve and for now do not bother `shrink_to_fit()` since the key
// strings are transient.
key.reserve(FLAGS_max_key_len * 8);
uint64_t window_idx = static_cast<uint64_t>(val) / window;
uint64_t offset = static_cast<uint64_t>(val) % window;
for (size_t level = 0; level < levels; ++level) {
uint64_t weight = key_gen_ctx.weights[level];
uint64_t offset = static_cast<uint64_t>(val) % window;
uint64_t mult = static_cast<uint64_t>(val) / window;
uint64_t pfx = mult * weight + (offset >= weight ? weight - 1 : offset);
key.append(GetStringFromInt(pfx));
uint64_t pfx;
if (level == 0) {
pfx = window_idx * weight;
} else {
pfx = 0;
}
pfx += offset >= weight ? weight - 1 : offset;
AppendIntToString(pfx, &key);
if (offset < weight) {
// Use the bottom 3 bits of offset as the number of trailing 'x's in the
// key. If the next key is going to be of the next level, then skip the
@ -461,8 +468,7 @@ extern inline std::string Key(int64_t val) {
}
break;
}
val = offset - weight;
window -= weight;
offset -= weight;
}
return key;

@ -158,10 +158,7 @@ class SharedState {
key_locks_.resize(FLAGS_column_families);
for (int i = 0; i < FLAGS_column_families; ++i) {
key_locks_[i].resize(num_locks);
for (auto& ptr : key_locks_[i]) {
ptr.reset(new port::Mutex);
}
key_locks_[i].reset(new port::Mutex[num_locks]);
}
#ifndef NDEBUG
if (FLAGS_read_fault_one_in) {
@ -227,20 +224,20 @@ class SharedState {
// Returns a lock covering `key` in `cf`.
port::Mutex* GetMutexForKey(int cf, int64_t key) {
return key_locks_[cf][key >> log2_keys_per_lock_].get();
return &key_locks_[cf][key >> log2_keys_per_lock_];
}
// Acquires locks for all keys in `cf`.
void LockColumnFamily(int cf) {
for (auto& mutex : key_locks_[cf]) {
mutex->Lock();
for (int i = 0; i < max_key_ >> log2_keys_per_lock_; ++i) {
key_locks_[cf][i].Lock();
}
}
// Releases locks for all keys in `cf`.
void UnlockColumnFamily(int cf) {
for (auto& mutex : key_locks_[cf]) {
mutex->Unlock();
for (int i = 0; i < max_key_ >> log2_keys_per_lock_; ++i) {
key_locks_[cf][i].Unlock();
}
}
@ -361,9 +358,9 @@ class SharedState {
std::unordered_set<size_t> no_overwrite_ids_;
std::unique_ptr<ExpectedStateManager> expected_state_manager_;
// Has to make it owned by a smart ptr as port::Mutex is not copyable
// Cannot store `port::Mutex` directly in vector since it is not copyable
// and storing it in the container may require copying depending on the impl.
std::vector<std::vector<std::unique_ptr<port::Mutex>>> key_locks_;
std::vector<std::unique_ptr<port::Mutex[]>> key_locks_;
std::atomic<bool> printing_verification_results_;
};

@ -78,7 +78,8 @@ bool ExpectedState::Exists(int cf, int64_t key) {
void ExpectedState::Reset() {
for (size_t i = 0; i < num_column_families_; ++i) {
for (size_t j = 0; j < max_key_; ++j) {
Delete(static_cast<int>(i), j, false /* pending */);
Value(static_cast<int>(i), j)
.store(SharedState::DELETION_SENTINEL, std::memory_order_relaxed);
}
}
}

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