Use 1ms CPU profiler sampling interval on Android by default

Use 1ms CPU profiler sampling interval on Android by default

This CL changes default sampling interval on Android from 5ms to 1ms so that it is the same on all platforms. All perf tests on modern devices (Galaxy Nexus, Nexus 7) show that 1ms should be long enough for profiling on mobile devices.

BUG=None
R=bmeurer@chromium.org, loislo@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=16526

[Benedikt Meurer, 2013-09-04 11:18:39]

What about older devices? 1ms is tough.

[loislo, 2013-09-04 11:18:41]

lgtm

[yurys, 2013-09-04 11:49:41]

On 2013/09/04 11:18:39, Benedikt Meurer wrote:
> What about older devices? 1ms is tough.

I don't think that we want to support DevTools CPU profiler on such devices.
They are likely to run old versions of Android and be incompatible with the
latest Chrome where the sampling rate is increased. Also 5ms rate seems to have
been chosen speculatively.

[Benedikt Meurer, 2013-09-04 12:06:28]

LGTM

[yurys, 2013-09-04 12:38:44]

Committed patchset #1 manually as r16526 (presubmit successful).

[Jakob Kummerow, 2013-09-04 12:46:05]

The 5ms tick interval resulted in a significant overall performance boost back
when the runtime profiler based its optimization decisions on these ticks, and
1ms ticks made it way too aggressive compared to desktop ia32 machines.

Now that optimization decisions use a different mechanism, +1 to this CL. 1ms is
more appropriate for profiling.