Allow GetThreadList() to report the start time of the current operation.

Summary: Allow GetThreadList() to report the start time of the current operation.

Test Plan:
./db_bench --benchmarks=fillrandom --num=100000 --threads=40 \
  --max_background_compactions=10 --max_background_flushes=3 \
  --thread_status_per_interval=1000 --key_size=16 --value_size=1000 \
  --num_column_families=10

Sample output:
          ThreadID ThreadType                    cfName    Operation        OP_StartTime         State
   140338840797248   High Pri column_family_name_000003        Flush 2015/03/09-17:49:59
   140338844991552   High Pri column_family_name_000004        Flush 2015/03/09-17:49:59
   140338849185856    Low Pri
   140338983403584    Low Pri
   140339008569408    Low Pri
   140338861768768    Low Pri
   140338924683328    Low Pri
   140338899517504    Low Pri
   140338853380160    Low Pri
   140338882740288    Low Pri
   140338865963072   High Pri column_family_name_000006        Flush 2015/03/09-17:49:59
   140338954043456    Low Pri
   140338857574464    Low Pri

Reviewers: igor, rven, sdong

Reviewed By: sdong

Subscribers: lgalanis, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34689

db/db_bench.cc

@@ -924,15 +924,28 @@ class Stats {
     std::vector<ThreadStatus> thread_list;
     FLAGS_env->GetThreadList(&thread_list);
 
-    fprintf(stderr, "\n%18s %10s %25s %12s %12s\n",
-        "ThreadID", "ThreadType", "cfName", "Operation", "State");
+    fprintf(stderr, "\n%18s %10s %25s %12s %20s %13s %12s\n",
+        "ThreadID", "ThreadType", "cfName", "Operation",
+        "OP_StartTime ", "ElapsedTime", "State");
 
+    int64_t current_time = 0;
+    Env::Default()->GetCurrentTime(&current_time);
     for (auto ts : thread_list) {
-      fprintf(stderr, "%18" PRIu64 " %10s %25s %12s %12s\n",
+      char elapsed_time[25];
+      if (ts.op_start_time != 0) {
+        AppendHumanMicros(
+            current_time - ts.op_start_time,
+            elapsed_time, 24);
+      } else {
+        elapsed_time[0] = 0;
+      }
+      fprintf(stderr, "%18" PRIu64 " %10s %25s %12s %20s %13s %12s\n",
           ts.thread_id,
           ThreadStatus::GetThreadTypeName(ts.thread_type).c_str(),
           ts.cf_name.c_str(),
           ThreadStatus::GetOperationName(ts.operation_type).c_str(),
+          ThreadStatus::TimeToString(ts.op_start_time).c_str(),
+          elapsed_time,
           ThreadStatus::GetStateName(ts.state_type).c_str());
     }
   }

include/rocksdb/thread_status.h

@@ -62,11 +62,14 @@ struct ThreadStatus {
                const std::string& _db_name,
                const std::string& _cf_name,
                const OperationType _operation_type,
+               const int64_t _op_start_time,
                const StateType _state_type) :
       thread_id(_id), thread_type(_thread_type),
       db_name(_db_name),
       cf_name(_cf_name),
-      operation_type(_operation_type), state_type(_state_type) {}
+      operation_type(_operation_type),
+      op_start_time(_op_start_time),
+      state_type(_state_type) {}
 
   // An unique ID for the thread.
   const uint64_t thread_id;
@@ -88,6 +91,10 @@ struct ThreadStatus {
   // The operation (high-level action) that the current thread is involved.
   const OperationType operation_type;
 
+  // The start time of the current status in the form of seconds since the
+  // Epoch, 1970-01-01 00:00:00 (UTC).
+  const int64_t op_start_time;
+
   // The state (lower-level action) that the current thread is involved.
   const StateType state_type;
 
@@ -99,6 +106,8 @@ struct ThreadStatus {
   // Obtain the name of an operation given its type.
   static const std::string& GetOperationName(OperationType op_type);
 
+  static const std::string TimeToString(int64_t op_start_time);
+
   // Obtain the name of a state given its type.
   static const std::string& GetStateName(StateType state_type);
 };

util/logging.cc

@@ -32,9 +32,18 @@ int AppendHumanMicros(uint64_t micros, char* output, int len) {
   } else if (micros < 10000000) {
     return snprintf(output, len, "%.3lf ms",
                     static_cast<double>(micros) / 1000);
-  } else {
+  } else if (micros < 1000000l * 60) {
     return snprintf(output, len, "%.3lf sec",
                     static_cast<double>(micros) / 1000000);
+  } else if (micros < 1000000l * 60 * 60) {
+    return snprintf(output, len, "%02" PRIu64 ":%05.3f",
+        micros / 1000000 / 60,
+        static_cast<double>(micros % 60000000) / 1000000);
+  } else {
+    return snprintf(output, len, "%02" PRIu64 ":%02" PRIu64 ":%05.3f",
+        micros / 1000000 / 3600,
+        (micros / 1000000 / 60) % 60,
+        static_cast<double>(micros % 60000000) / 1000000);
   }
 }
 

util/thread_status_impl.cc

@@ -4,6 +4,7 @@
 // of patent rights can be found in the PATENTS file in the same directory.
 //
 
+#include "rocksdb/env.h"
 #include "rocksdb/thread_status.h"
 #include "util/thread_operation.h"
 
@@ -27,6 +28,14 @@ const std::string& ThreadStatus::GetStateName(
   return global_state_table[state_type].name;
 }
 
+const std::string ThreadStatus::TimeToString(
+    int64_t time) {
+  if (time == 0) {
+    return "";
+  }
+  return Env::Default()->TimeToString(time);
+}
+
 #else
 
 const std::string& ThreadStatus::GetThreadTypeName(

util/thread_status_updater.cc

@@ -63,6 +63,15 @@ void ThreadStatusUpdater::SetThreadOperation(
   data->operation_type.store(type, std::memory_order_relaxed);
 }
 
+void ThreadStatusUpdater::SetOperationStartTime(const int64_t start_time) {
+  auto* data = InitAndGet();
+  if (!data->enable_tracking) {
+    assert(data->cf_key.load(std::memory_order_relaxed) == nullptr);
+    return;
+  }
+  data->op_start_time.store(start_time, std::memory_order_relaxed);
+}
+
 void ThreadStatusUpdater::ClearThreadOperation() {
   auto* data = InitAndGet();
   if (!data->enable_tracking) {
@@ -116,6 +125,7 @@ Status ThreadStatusUpdater::GetThreadList(
     const std::string* cf_name = nullptr;
     ThreadStatus::OperationType op_type = ThreadStatus::OP_UNKNOWN;
     ThreadStatus::StateType state_type = ThreadStatus::STATE_UNKNOWN;
+    int64_t op_start_time = 0;
     if (cf_info != nullptr) {
       db_name = &cf_info->db_name;
       cf_name = &cf_info->cf_name;
@@ -123,6 +133,8 @@ Status ThreadStatusUpdater::GetThreadList(
           std::memory_order_relaxed);
       // display lower-level info only when higher-level info is available.
       if (op_type != ThreadStatus::OP_UNKNOWN) {
+        op_start_time = thread_data->op_start_time.load(
+            std::memory_order_relaxed);
         state_type = thread_data->state_type.load(
             std::memory_order_relaxed);
       }
@@ -131,7 +143,7 @@ Status ThreadStatusUpdater::GetThreadList(
         thread_data->thread_id, thread_type,
         db_name ? *db_name : "",
         cf_name ? *cf_name : "",
-        op_type, state_type);
+        op_type, op_start_time, state_type);
   }
 
   return Status::OK();

util/thread_status_updater.h

@@ -68,6 +68,7 @@ struct ThreadStatusData {
     thread_type.store(ThreadStatus::USER);
     cf_key.store(nullptr);
     operation_type.store(ThreadStatus::OP_UNKNOWN);
+    op_start_time.store(0);
     state_type.store(ThreadStatus::STATE_UNKNOWN);
   }
 
@@ -85,6 +86,7 @@ struct ThreadStatusData {
   std::atomic<ThreadStatus::ThreadType> thread_type;
   std::atomic<const void*> cf_key;
   std::atomic<ThreadStatus::OperationType> operation_type;
+  std::atomic<int64_t> op_start_time;
   std::atomic<ThreadStatus::StateType> state_type;
 #endif  // ROCKSDB_USING_THREAD_STATUS
 };
@@ -124,6 +126,8 @@ class ThreadStatusUpdater {
   // Update the thread operation of the current thread.
   void SetThreadOperation(const ThreadStatus::OperationType type);
 
+  void SetOperationStartTime(const int64_t start_time);
+
   // Clear thread operation of the current thread.
   void ClearThreadOperation();
 

util/thread_status_util.cc

@@ -54,6 +54,15 @@ void ThreadStatusUtil::SetThreadOperation(ThreadStatus::OperationType op) {
     return;
   }
 
+  if (op != ThreadStatus::OP_UNKNOWN) {
+    int64_t current_time = 0;
+    Env::Default()->GetCurrentTime(&current_time);
+    thread_updater_local_cache_->SetOperationStartTime(current_time);
+  } else {
+    // TDOO(yhchiang): we could report the time when we set operation to
+    // OP_UNKNOWN once the whole instrumentation has been done.
+    thread_updater_local_cache_->SetOperationStartTime(0);
+  }
   thread_updater_local_cache_->SetThreadOperation(op);
 }