polish benchmark protos

test/proto/benchmarks/control.proto

@@ -97,6 +97,7 @@ message ClientConfig {
   RpcType rpc_type = 8;
   LoadParams load_params = 10;
   PayloadConfig payload_config = 11;
+  HistogramParams histogram_params = 12;
 }
 
 message ClientStatus {
@@ -118,6 +119,7 @@ message ClientArgs {
 message ServerConfig {
   ServerType server_type = 1;
   SecurityParams security_params = 2;
+  string host = 3;
   int32 port = 4;
   // only for async server
   int32 async_server_threads = 7;

test/proto/benchmarks/stats.proto

@@ -32,16 +32,24 @@ syntax = "proto3";
 package grpc.testing;
 
 message ServerStats {
-  // wall clock time
+  // wall clock time change since last reset
   double time_elapsed = 1;
 
-  // user time used by the server process and threads
+  // change in user time used by the server since last reset
   double time_user = 2;
 
-  // server time used by the server process and all threads
+  // change in server time used by the server process and all threads since
+  // last reset
   double time_system = 3;
 }
 
+// Histogram params based on grpc/support/histogram.c
+message HistogramParams {
+  double resolution = 1;  // first bucket is [0, 1 + resolution)
+  double max_possible = 2;  // use enough buckets to allow this value
+}
+
+// Histogram data based on grpc/support/histogram.c
 message HistogramData {
   repeated uint32 bucket = 1;
   double min_seen = 2;
@@ -53,6 +61,8 @@ message HistogramData {
 
 message ClientStats {
   HistogramData latencies = 1;
+
+  // See ServerStats for details.
   double time_elapsed = 2;
   double time_user = 3;
   double time_system = 4;