Measuring data use of different ModelTypes in Sync Service.

sync/engine/commit.cc

Index: sync/engine/commit.cc
diff --git a/sync/engine/commit.cc b/sync/engine/commit.cc
index f607be4c8b4e91499e2d1184c9c8d491d6b0d7ba..51809d02b1c6c7b1c59533b98bbf3fd5cfc19634 100644
--- a/sync/engine/commit.cc
+++ b/sync/engine/commit.cc
@@ -4,6 +4,7 @@
 
 #include "sync/engine/commit.h"
 
+#include "base/metrics/sparse_histogram.h"
 #include "base/trace_event/trace_event.h"
 #include "sync/engine/commit_contribution.h"
 #include "sync/engine/commit_processor.h"
@@ -14,6 +15,13 @@
 #include "sync/internal_api/public/events/commit_response_event.h"
 #include "sync/sessions/sync_session.h"
 
+#define UMA_HISTOGRAM_SPARSE_SLOWLY_WITH_VALUE(name, sample, value)     \

[Nicolas Zea, 2015/08/07 22:57:36]

Can these macros be pulled into a header file so they're not duplicated (AFAICT
they're the same in the various files?)

[amohammadkhan, 2015/08/08 00:50:19]

Yes you are right. I want to ask UMA team to add to sparseHistogram header file,
if it is possible. If they do not agree, can I put them somewhere in sync?

+  do {                                                                  \
+    base::HistogramBase* histogram = base::SparseHistogram::FactoryGet( \
+        name, base::HistogramBase::kUmaTargetedHistogramFlag);          \
+    histogram->AddCount(sample, value);                                 \
+  } while (0)
+
 namespace syncer {
 
 Commit::Commit(ContributionMap contributions,
@@ -70,11 +78,22 @@ Commit* Commit::Init(
       enabled_types,
       commit_message);
 
+  int previous_message_size = message.ByteSize();
   // Finally, serialize all our contributions.
   for (std::map<ModelType, CommitContribution*>::const_iterator it =
            contributions.begin();
        it != contributions.end(); ++it) {
     it->second->AddToCommitMessage(&message);
+    int current_entry_size = message.ByteSize() - previous_message_size;
+    previous_message_size = message.ByteSize();
+    if (current_entry_size > 0) {
+      UMA_HISTOGRAM_SPARSE_SLOWLY_WITH_VALUE("DataUse.Sync.Upload.Bytes",
+                                             ModelTypeToHistogramInt(it->first),
+                                             current_entry_size);
+    }
+    UMA_HISTOGRAM_SPARSE_SLOWLY_WITH_VALUE("DataUse.Sync.Upload.Bytes",

[Nicolas Zea, 2015/08/07 22:57:36]

Why increment by 1 here?

[amohammadkhan, 2015/08/08 00:50:19]

You are right. It is incorrect. The histogram name should change to
DataUse.Sync.Upload.Count.

+                                           ModelTypeToHistogramInt(it->first),
+                                           1);
   }
 
   // If we made it this far, then we've successfully prepared a commit message.