Fix a bug in PosixClock (#9695)

Summary:
Multiplier here should be 1e6 to get microseconds.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9695

Reviewed By: ajkr

Differential Revision: D34897086

Pulled By: jay-zhuang

fbshipit-source-id: 9c1d0811ea740ba0a007edc2da199edbd000b88b

db/compaction/compaction_job.cc

@@ -1315,7 +1315,7 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
   }
 #endif  // !ROCKSDB_LITE
 
-  uint64_t prev_cpu_micros = db_options_.clock->CPUNanos() / 1000;
+  uint64_t prev_cpu_micros = db_options_.clock->CPUMicros();
 
   ColumnFamilyData* cfd = sub_compact->compaction->column_family_data();
 
@@ -1669,7 +1669,7 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
   }
 
   sub_compact->compaction_job_stats.cpu_micros =
-      db_options_.clock->CPUNanos() / 1000 - prev_cpu_micros;
+      db_options_.clock->CPUMicros() - prev_cpu_micros;
 
   if (measure_io_stats_) {
     sub_compact->compaction_job_stats.file_write_nanos +=

db/flush_job.cc

@@ -361,7 +361,7 @@ Status FlushJob::MemPurge() {
 
   // Measure purging time.
   const uint64_t start_micros = clock_->NowMicros();
-  const uint64_t start_cpu_micros = clock_->CPUNanos() / 1000;
+  const uint64_t start_cpu_micros = clock_->CPUMicros();
 
   MemTable* new_mem = nullptr;
   // For performance/log investigation purposes:
@@ -614,7 +614,7 @@ Status FlushJob::MemPurge() {
     TEST_SYNC_POINT("DBImpl::FlushJob:MemPurgeUnsuccessful");
   }
   const uint64_t micros = clock_->NowMicros() - start_micros;
-  const uint64_t cpu_micros = clock_->CPUNanos() / 1000 - start_cpu_micros;
+  const uint64_t cpu_micros = clock_->CPUMicros() - start_cpu_micros;
   ROCKS_LOG_INFO(db_options_.info_log,
                  "[%s] [JOB %d] Mempurge lasted %" PRIu64
                  " microseconds, and %" PRIu64
@@ -800,7 +800,7 @@ Status FlushJob::WriteLevel0Table() {
       ThreadStatus::STAGE_FLUSH_WRITE_L0);
   db_mutex_->AssertHeld();
   const uint64_t start_micros = clock_->NowMicros();
-  const uint64_t start_cpu_micros = clock_->CPUNanos() / 1000;
+  const uint64_t start_cpu_micros = clock_->CPUMicros();
   Status s;
 
   std::vector<BlobFileAddition> blob_file_additions;
@@ -993,7 +993,7 @@ Status FlushJob::WriteLevel0Table() {
   // Note that here we treat flush as level 0 compaction in internal stats
   InternalStats::CompactionStats stats(CompactionReason::kFlush, 1);
   const uint64_t micros = clock_->NowMicros() - start_micros;
-  const uint64_t cpu_micros = clock_->CPUNanos() / 1000 - start_cpu_micros;
+  const uint64_t cpu_micros = clock_->CPUMicros() - start_cpu_micros;
   stats.micros = micros;
   stats.cpu_micros = cpu_micros;
 

env/env_posix.cc

@@ -166,7 +166,7 @@ class PosixClock : public SystemClock {
     defined(OS_AIX) || (defined(__MACH__) && defined(__MAC_10_12))
     struct timespec ts;
     clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);
-    return static_cast<uint64_t>(ts.tv_sec) * 1000000000;
+    return (static_cast<uint64_t>(ts.tv_sec) * 1000000000 + ts.tv_nsec) / 1000;
 #endif
     return 0;
   }