Add --stats_interval_seconds to db_bench

Summary:
The --stats_interval_seconds determines interval for stats reporting
and overrides --stats_interval when set. I also changed tools/benchmark.sh
to report stats every 60 seconds so I can avoid trying to figure out a
good value for --stats_interval per test and per storage device.

Task ID: #6631621

Blame Rev:

Test Plan:
run tools/run_flash_bench, look at output

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D36189

db/db_bench.cc

@@ -476,6 +476,9 @@ static rocksdb::Env* FLAGS_env = rocksdb::Env::Default();
 DEFINE_int64(stats_interval, 0, "Stats are reported every N operations when "
              "this is greater than zero. When 0 the interval grows over time.");
 
+DEFINE_int64(stats_interval_seconds, 0, "Report stats every N seconds. This "
+             "overrides stats_interval when both are > 0.");
+
 DEFINE_int32(stats_per_interval, 0, "Reports additional stats per interval when"
              " this is greater than 0.");
 
@@ -992,6 +995,18 @@ class Stats {
         fprintf(stderr, "... finished %" PRIu64 " ops%30s\r", done_, "");
       } else {
         double now = FLAGS_env->NowMicros();
+        int64_t usecs_since_last = now - last_report_finish_;
+
+        // Determine whether to print status where interval is either
+        // each N operations or each N seconds.
+
+        if (FLAGS_stats_interval_seconds &&
+            usecs_since_last < (FLAGS_stats_interval_seconds * 1000000)) {
+          // Don't check again for this many operations
+          next_report_ += FLAGS_stats_interval;
+
+        } else {
+
           fprintf(stderr,
                   "%s ... thread %d: (%" PRIu64 ",%" PRIu64 ") ops and "
                   "(%.1f,%.1f) ops/second in (%.6f,%.6f) seconds\n",
@@ -999,7 +1014,7 @@ class Stats {
                   id_,
                   done_ - last_report_done_, done_,
                   (done_ - last_report_done_) /
-                ((now - last_report_finish_) / 1000000.0),
+                  (usecs_since_last / 1000000.0),
                   done_ / ((now - start_) / 1000000.0),
                   (now - last_report_finish_) / 1000000.0,
                   (now - start_) / 1000000.0);
@@ -1023,6 +1038,7 @@ class Stats {
           last_report_finish_ = now;
           last_report_done_ = done_;
         }
+      }
       if (id_ == 0 && FLAGS_thread_status_per_interval) {
         PrintThreadStatus();
       }
@@ -3389,6 +3405,12 @@ int main(int argc, char** argv) {
     FLAGS_db = default_db_path;
   }
 
+  if (FLAGS_stats_interval_seconds > 0) {
+    // When both are set then FLAGS_stats_interval determines the frequency
+    // at which the timer is checked for FLAGS_stats_interval_seconds
+    FLAGS_stats_interval = 1000;
+  }
+
   rocksdb::Benchmark benchmark;
   benchmark.Run();
   return 0;

tools/benchmark.sh

@@ -77,7 +77,7 @@ const_params="
   \
   --statistics=1 \
   --stats_per_interval=1 \
-  --stats_interval=$((1 * M)) \
+  --stats_interval_seconds=60 \
   --histogram=1 \
   \
   --memtablerep=skip_list \