pereman2 / pb

experimentation personal library

C++ Function hardware counter profiler

void to_profile() {
  PbProfileFunctionF(f, __FUNCTION__, PB_PROFILE_CACHE | PB_PROFILE_BRANCH);
  for (int i = 0; i < 1000000; i++) {
    int *a = new int;
    delete a;
  }
int main() {
  PbProfilerStart("profile.log");
}

after a fio run in ceph benchmarks testing ceph's operator new and operator delete

Adding function allocate
Adding function deallocate
Adding function allocate
Adding function _kv_sync_thread
Adding function queue_transactions
Results 2021523-ceph-osd.profile.log:
Function _kv_sync_thread:
                cycles: samples:               1, p50:     12236831156 p99     12236831156
          cache_misses: samples:               1, p50:        97487290 p99        97487290
         branch_misses: samples:               1, p50:        43208800 p99        43208800
Function allocate:
                cycles: samples:        12000849, p50:              90 p99             310
          cache_misses: samples:        12000849, p50:               0 p99               7
         branch_misses: samples:        12000847, p50:               0 p99               3
Function allocate:
                cycles: samples:          540740, p50:              90 p99             299
          cache_misses: samples:          540740, p50:               0 p99               7
         branch_misses: samples:          540742, p50:               0 p99               2
Function deallocate:
                cycles: samples:        12541589, p50:              95 p99             374
          cache_misses: samples:        12541589, p50:               0 p99               4
         branch_misses: samples:        12541589, p50:               0 p99               0
Function queue_transactions:
                cycles: samples:          101413, p50:         4329800 p99        10097291

running tests in bluestore

./bin/ceph_test_objectstore --gtest_filter="ObjectStore/StoreTest.Synthetic/1" --log_to_stderr=false --log_file=log.log --debug_bluestore=30 --plugin_dir=lib
cp profile.log ~/pb/
./stats

Results:
Function _kv_sync_thread:
                cycles: samples:                   20, avg:           3518369289 stdev     894760028.047122 p99          33426951686
        cpu_migrations: samples:                   17, avg:          20186220969 stdev     624304422.307552 p99          69268077172
          cache_misses: samples:                   37, avg:               220772 stdev        310825.073971 p99              1197985
         branch_misses: samples:                   37, avg:                46394 stdev         66744.329122 p99               246405
Function decode_some:
                cycles: samples:                21845, avg:                14970 stdev         17361.333877 p99                69419
          cache_misses: samples:                21846, avg:                  109 stdev           156.393734 p99                  592
         branch_misses: samples:                21845, avg:                   48 stdev            69.620399 p99                  313
Function decode_some:
                cycles: samples:                 9699, avg:                29868 stdev         25009.526705 p99               110450
          cache_misses: samples:                 9698, avg:                  221 stdev           199.484335 p99                  777
         branch_misses: samples:                 9699, avg:                  108 stdev           103.879738 p99                  456
Function queue_transactions:
                cycles: samples:                 8611, avg:              2684805 stdev      45093134.107070 p99             17484141
        cpu_migrations: samples:                   11, avg:             39464951 stdev      44859124.146431 p99            141977459
          cache_misses: samples:                 8622, avg:                 3963 stdev          3394.946097 p99                15047
         branch_misses: samples:                 8622, avg:                 1413 stdev          1290.311978 p99                 7319