Stop holding histogram for a long time

test/cpp/qps/client.h

@@ -112,6 +112,17 @@ class ClientRequestCreator<ByteBuffer> {
   }
 };
 
+class HistogramEntry GRPC_FINAL {
+ public:
+  HistogramEntry(): used_(false) {}
+  bool used() const {return used_;}
+  double value() const {return value_;}
+  void set_value(double v) {used_ = true; value_ = v;}
+ private:
+  bool used_;
+  double value_;
+};
+
 class Client {
  public:
   Client() : timer_(new UsageTimer), interarrival_timer_() {}
@@ -162,7 +173,7 @@ class Client {
 
   void EndThreads() { threads_.clear(); }
 
-  virtual bool ThreadFunc(Histogram* histogram, size_t thread_idx) = 0;
+  virtual bool ThreadFunc(HistogramEntry* histogram, size_t thread_idx) = 0;
 
   void SetupLoadTest(const ClientConfig& config, size_t num_threads) {
     // Set up the load distribution based on the number of threads
@@ -215,7 +226,6 @@ class Client {
    public:
     Thread(Client* client, size_t idx)
         : done_(false),
-          new_stats_(nullptr),
           client_(client),
           idx_(idx),
           impl_(&Thread::ThreadFunc, this) {}
@@ -230,14 +240,10 @@ class Client {
 
     void BeginSwap(Histogram* n) {
       std::lock_guard<std::mutex> g(mu_);
-      new_stats_ = n;
+      n->Swap(&histogram_);
     }
 
     void EndSwap() {
-      std::unique_lock<std::mutex> g(mu_);
-      while (new_stats_ != nullptr) {
-        cv_.wait(g);
-      };
     }
 
     void MergeStatsInto(Histogram* hist) {
@@ -252,9 +258,13 @@ class Client {
     void ThreadFunc() {
       for (;;) {
         // run the loop body
-        const bool thread_still_ok = client_->ThreadFunc(&histogram_, idx_);
-        // lock, see if we're done
+        HistogramEntry entry;
+        const bool thread_still_ok = client_->ThreadFunc(&entry, idx_);
+        // lock, update histogram if needed and see if we're done
         std::lock_guard<std::mutex> g(mu_);
+        if (entry.used()) {
+          histogram_.Add(entry.value());
+        }
         if (!thread_still_ok) {
           gpr_log(GPR_ERROR, "Finishing client thread due to RPC error");
           done_ = true;
@@ -262,17 +272,10 @@ class Client {
         if (done_) {
           return;
         }
-        // check if we're resetting stats, swap out the histogram if so
-        if (new_stats_) {
-          new_stats_->Swap(&histogram_);
-          new_stats_ = nullptr;
-          cv_.notify_one();
-        }
       }
     }
 
     std::mutex mu_;
-    std::condition_variable cv_;
     bool done_;
     Histogram* new_stats_;
     Histogram histogram_;

test/cpp/qps/client_async.cc

@@ -48,7 +48,6 @@
 #include <grpc++/generic/generic_stub.h>
 #include <grpc/grpc.h>
 #include <grpc/support/cpu.h>
-#include <grpc/support/histogram.h>
 #include <grpc/support/log.h>
 
 #include "src/proto/grpc/testing/services.grpc.pb.h"
@@ -64,7 +63,7 @@ class ClientRpcContext {
   ClientRpcContext() {}
   virtual ~ClientRpcContext() {}
   // next state, return false if done. Collect stats when appropriate
-  virtual bool RunNextState(bool, Histogram* hist) = 0;
+  virtual bool RunNextState(bool, HistogramEntry* entry) = 0;
   virtual ClientRpcContext* StartNewClone() = 0;
   static void* tag(ClientRpcContext* c) { return reinterpret_cast<void*>(c); }
   static ClientRpcContext* detag(void* t) {
@@ -104,7 +103,7 @@ class ClientRpcContextUnaryImpl : public ClientRpcContext {
       alarm_.reset(new Alarm(cq_, next_issue_(), ClientRpcContext::tag(this)));
     }
   }
-  bool RunNextState(bool ok, Histogram* hist) GRPC_OVERRIDE {
+  bool RunNextState(bool ok, HistogramEntry* entry) GRPC_OVERRIDE {
     switch (next_state_) {
       case State::READY:
         start_ = UsageTimer::Now();
@@ -114,7 +113,7 @@ class ClientRpcContextUnaryImpl : public ClientRpcContext {
         next_state_ = State::RESP_DONE;
         return true;
       case State::RESP_DONE:
-        hist->Add((UsageTimer::Now() - start_) * 1e9);
+        entry->set_value((UsageTimer::Now() - start_) * 1e9);
         callback_(status_, &response_);
         next_state_ = State::INVALID;
         return false;
@@ -201,7 +200,7 @@ class AsyncClient : public ClientImpl<StubType, RequestType> {
     }
   }
 
-  bool ThreadFunc(Histogram* histogram,
+  bool ThreadFunc(HistogramEntry* entry,
                   size_t thread_idx) GRPC_OVERRIDE GRPC_FINAL {
     void* got_tag;
     bool ok;
@@ -209,7 +208,7 @@ class AsyncClient : public ClientImpl<StubType, RequestType> {
     if (cli_cqs_[thread_idx]->Next(&got_tag, &ok)) {
       // Got a regular event, so process it
       ClientRpcContext* ctx = ClientRpcContext::detag(got_tag);
-      if (!ctx->RunNextState(ok, histogram)) {
+      if (!ctx->RunNextState(ok, entry)) {
         // The RPC and callback are done, so clone the ctx
         // and kickstart the new one
         auto clone = ctx->StartNewClone();
@@ -298,7 +297,7 @@ class ClientRpcContextStreamingImpl : public ClientRpcContext {
     stream_ = start_req_(stub_, &context_, cq, ClientRpcContext::tag(this));
     next_state_ = State::STREAM_IDLE;
   }
-  bool RunNextState(bool ok, Histogram* hist) GRPC_OVERRIDE {
+  bool RunNextState(bool ok, HistogramEntry* entry) GRPC_OVERRIDE {
     while (true) {
       switch (next_state_) {
         case State::STREAM_IDLE:
@@ -330,7 +329,7 @@ class ClientRpcContextStreamingImpl : public ClientRpcContext {
           return true;
           break;
         case State::READ_DONE:
-          hist->Add((UsageTimer::Now() - start_) * 1e9);
+          entry->set_value((UsageTimer::Now() - start_) * 1e9);
           callback_(status_, &response_);
           next_state_ = State::STREAM_IDLE;
           break;  // loop around
@@ -430,7 +429,7 @@ class ClientRpcContextGenericStreamingImpl : public ClientRpcContext {
                          ClientRpcContext::tag(this));
     next_state_ = State::STREAM_IDLE;
   }
-  bool RunNextState(bool ok, Histogram* hist) GRPC_OVERRIDE {
+  bool RunNextState(bool ok, HistogramEntry* entry) GRPC_OVERRIDE {
     while (true) {
       switch (next_state_) {
         case State::STREAM_IDLE:
@@ -462,7 +461,7 @@ class ClientRpcContextGenericStreamingImpl : public ClientRpcContext {
           return true;
           break;
         case State::READ_DONE:
-          hist->Add((UsageTimer::Now() - start_) * 1e9);
+          entry->set_value((UsageTimer::Now() - start_) * 1e9);
           callback_(status_, &response_);
           next_state_ = State::STREAM_IDLE;
           break;  // loop around

test/cpp/qps/client_sync.cc

@@ -46,7 +46,6 @@
 #include <grpc++/server_builder.h>
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
-#include <grpc/support/histogram.h>
 #include <grpc/support/host_port.h>
 #include <grpc/support/log.h>
 #include <grpc/support/time.h>
@@ -55,7 +54,6 @@
 #include "src/core/lib/profiling/timers.h"
 #include "src/proto/grpc/testing/services.grpc.pb.h"
 #include "test/cpp/qps/client.h"
-#include "test/cpp/qps/histogram.h"
 #include "test/cpp/qps/interarrival.h"
 #include "test/cpp/qps/usage_timer.h"
 
@@ -100,7 +98,7 @@ class SynchronousUnaryClient GRPC_FINAL : public SynchronousClient {
   }
   ~SynchronousUnaryClient() { EndThreads(); }
 
-  bool ThreadFunc(Histogram* histogram, size_t thread_idx) GRPC_OVERRIDE {
+  bool ThreadFunc(HistogramEntry* entry, size_t thread_idx) GRPC_OVERRIDE {
     WaitToIssue(thread_idx);
     auto* stub = channels_[thread_idx % channels_.size()].get_stub();
     double start = UsageTimer::Now();
@@ -108,7 +106,7 @@ class SynchronousUnaryClient GRPC_FINAL : public SynchronousClient {
     grpc::ClientContext context;
     grpc::Status s =
         stub->UnaryCall(&context, request_, &responses_[thread_idx]);
-    histogram->Add((UsageTimer::Now() - start) * 1e9);
+    entry->set_value((UsageTimer::Now() - start) * 1e9);
     return s.ok();
   }
 };
@@ -139,13 +137,13 @@ class SynchronousStreamingClient GRPC_FINAL : public SynchronousClient {
     delete[] context_;
   }
 
-  bool ThreadFunc(Histogram* histogram, size_t thread_idx) GRPC_OVERRIDE {
+  bool ThreadFunc(HistogramEntry* entry, size_t thread_idx) GRPC_OVERRIDE {
     WaitToIssue(thread_idx);
     GPR_TIMER_SCOPE("SynchronousStreamingClient::ThreadFunc", 0);
     double start = UsageTimer::Now();
     if (stream_[thread_idx]->Write(request_) &&
         stream_[thread_idx]->Read(&responses_[thread_idx])) {
-      histogram->Add((UsageTimer::Now() - start) * 1e9);
+      entry->set_value((UsageTimer::Now() - start) * 1e9);
       return true;
     }
     return false;