[tracing] Increase backtrace map capacity on Linux.

[tracing] Increase backtrace map capacity on Linux.

On Linux when startup tracing is used with native heap profiling, ~45K
unique backtraces are generated, while backtrace map only allows for 32K.
This CL bumps the max number of unique backtraces.

BUG=633309
Committed: https://crrev.com/ece847f3cd16baa05a9b896ba7ae58b23540a178
Cr-Commit-Position: refs/heads/master@{#410203}

[Dmitry Skiba, 2016-08-01 23:33:14]

dskiba@google.com changed reviewers:
+ primiano@chromium.org

[Primiano Tucci (use gerrit), 2016-08-03 13:15:01]

LGTM

https://codereview.chromium.org/2204743003/diff/1/base/trace_event/heap_profi...
File base/trace_event/heap_profiler_allocation_register.h (right):

https://codereview.chromium.org/2204743003/diff/1/base/trace_event/heap_profi...
base/trace_event/heap_profiler_allocation_register.h:313: static const size_t
kBacktraceCapacity = 55000;  // 45K was observed on Linux
maybe just go for 64k or 128k? On linux we usually have wayyyy more memory.

[Dmitry Skiba, 2016-08-05 21:33:22]

On 2016/08/03 13:15:01, Primiano Tucci wrote:
> LGTM
> 
>
https://codereview.chromium.org/2204743003/diff/1/base/trace_event/heap_profi...
> File base/trace_event/heap_profiler_allocation_register.h (right):
> 
>
https://codereview.chromium.org/2204743003/diff/1/base/trace_event/heap_profi...
> base/trace_event/heap_profiler_allocation_register.h:313: static const size_t
> kBacktraceCapacity = 55000;  // 45K was observed on Linux
> maybe just go for 64k or 128k? On linux we usually have wayyyy more memory.

I actually plan to introduce chunked allocations to FixedHashMap (so that it
doesn't allocate everything at once, but in chunks), and with that I'll bump
values 2x.

[Dmitry Skiba, 2016-08-05 21:33:33]

The CQ bit was checked by dskiba@google.com

[commit-bot: I haz the power, 2016-08-05 21:34:21]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-05 22:51:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-05 22:52:54]

Description was changed from

==========
[tracing] Increase backtrace map capacity on Linux.

On Linux when startup tracing is used with native heap profiling, ~45K
unique backtraces are generated, while backtrace map only allows for 32K.
This CL bumps the max number of unique backtraces.

BUG=633309
==========

to

==========
[tracing] Increase backtrace map capacity on Linux.

On Linux when startup tracing is used with native heap profiling, ~45K
unique backtraces are generated, while backtrace map only allows for 32K.
This CL bumps the max number of unique backtraces.

BUG=633309

Committed: https://crrev.com/ece847f3cd16baa05a9b896ba7ae58b23540a178
Cr-Commit-Position: refs/heads/master@{#410203}
==========

[commit-bot: I haz the power, 2016-08-05 22:52:55]

Patchset 1 (id:??) landed as
https://crrev.com/ece847f3cd16baa05a9b896ba7ae58b23540a178
Cr-Commit-Position: refs/heads/master@{#410203}