Add a percentage to each metric in the V8 timeline plot

Add a percentage to each metric in the V8 timeline plot

With the percentage, we can easily figure out how much execution time is spent in what metric.

c.f. https://docs.google.com/a/google.com/file/d/0B7GPzKNdEGeQU04ySy1qOWNuLWs/edit

BUG=

Committed: https://code.google.com/p/v8/source/detail?r=13415

[haraken, 2013-01-17 13:37:26]

yang: Could you take a look?

A graph result is here:
https://docs.google.com/a/google.com/file/d/0B7GPzKNdEGeQU04ySy1qOWNuLWs/edit

[Yang, 2013-01-17 14:42:37]

On 2013/01/17 13:37:26, haraken1 wrote:
> yang: Could you take a look?
> 
> A graph result is here:
> https://docs.google.com/a/google.com/file/d/0B7GPzKNdEGeQU04ySy1qOWNuLWs/edit

I dont think this is correct. Due to concurrency (parallel recompilation for
example), the sum may be larger than 100%. At the point you attempt to calculate
the percentages, we already know the plot range (xrange_start and xrange_end).
You can now, for each event type, merge all the ranges, exclude the intervals
[-Infinity, xrange_start] and [xrange_end, +Infinity] from those ranges, and
calculate the sum of ranges, and then divide that by the maximum, which is
xrange_end - xrange_start.

[haraken, 2013-01-17 14:52:46]

> You can now, for each event type, merge all the ranges, exclude the intervals
> [-Infinity, xrange_start] and [xrange_end, +Infinity] from those ranges, and
> calculate the sum of ranges, and then divide that by the maximum, which is
> xrange_end - xrange_start.

Makes sense. Updated the patch.

[haraken, 2013-01-17 15:09:58]

As discussed offline, I used ExcludeRanges().

[Yang, 2013-01-17 15:29:28]

On 2013/01/17 15:09:58, haraken1 wrote:
> As discussed offline, I used ExcludeRanges().

LGTM.