Serialize edge counts instead of indexes in heap snapshot.

Serialize edge counts instead of indexes in heap snapshot.

The serialized node structure currently holds an index
of its first containment edge in the edges array.
The index can be quite big (up to 7 digits for large snapshots).
The patch changes the serialization format to pass
node containment edge count instead. For most nodes the count
is just a single digit number.
This reduces serialized snapshot size and therefore its transfer time.

Committed: https://code.google.com/p/v8/source/detail?r=11728

[loislo, 2012-06-05 17:05:15]

https://chromiumcodereview.appspot.com/10534008/diff/1/src/profile-generator.cc
File src/profile-generator.cc (right):

https://chromiumcodereview.appspot.com/10534008/diff/1/src/profile-generator....
src/profile-generator.cc:3329: SerializeEdge(edges[i], i == 0);
please add an assert with check that edge's fromNodeIndex is monotonically
increasing.

[alf, 2012-06-05 17:20:27]

https://chromiumcodereview.appspot.com/10534008/diff/1/src/profile-generator.cc
File src/profile-generator.cc (right):

https://chromiumcodereview.appspot.com/10534008/diff/1/src/profile-generator....
src/profile-generator.cc:3329: SerializeEdge(edges[i], i == 0);
On 2012/06/05 17:05:15, loislo wrote:
> please add an assert with check that edge's fromNodeIndex is monotonically
> increasing.

Done.

[loislo, 2012-06-05 18:28:45]

lgtm