Re: [PATCH 1/3] perf sort: Add 'addr' sort key

From: Namhyung Kim
Date: Wed Mar 27 2013 - 02:12:41 EST


Hi Ingo,

On Tue, 26 Mar 2013 15:40:23 +0100, Ingo Molnar wrote:
> * Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
>> From: Namhyung Kim <namhyung.kim@xxxxxxx>
>>
>> New addr sort key provides a way to sort the entries by the symbol
>> addresses.
>
> No objections from me - just wondering about the motivation: why would we
> want to sort by symbol address?

In fact, it came from bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=55561

>
> Perhaps to see the overhead layout/distribution within a DSO, to better
> cache-pack hot functions by placing them next to each other?
>
> Putting a short usecase into the changelog (or even better, the
> documentation) would be nice.

Well, I didn't thought it much, but yeah, aforementioned usecase looks
promising. Also it might be useful to find out which part is the
hotpath in a function if you have some really big functions (possibly
due to auto-inlining or something).

Arnaldo, do you have other usecase/scenario in mind?

Thanks,
Namhyung
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