Re: [PATCH] perf tools: Fix JIT profiling on heap

From: Gaurav Jain
Date: Wed Jan 22 2014 - 18:44:30 EST


> On Jan 17, 2014, at 2:44 AM, "Namhyung Kim" <namhyung@xxxxxxxxxx> wrote:
>
> Hi Gaurav,
>
>> On Thu, 16 Jan 2014 20:23:27 +0000, Gaurav Jain wrote:
>> On 1/16/14, 9:37 AM, "Arnaldo Carvalho de Melo" <acme@xxxxxxxxxxxxxxxxxx>
>> wrote:
>> Does perf support data mappings from perf map files? Could you please
>> share an example of how I may be able to use this.
>
> IIUC there's no difference between function and data mapping. So you
> can use same perf map file for both - in fact there's no way to use
> different map file in a single task. I guess perf will use it to find
> only function symbols in function mappings and variables in data
> mapping based on the address it accesses.
>
> What I wasn't sure is whether JIT program also produces some dynamic data.
> And I think only perf mem command cares about data mappings, no?

I don't think we generate symbols for dynamic data at the moment. There may be uses in the future. I don't know about other JIT programs.

If we can include this behaviour it would be great, but I don't have a way to test it. I'd guess if somebody had a valid use case, they would report the issue. Otherwise, the patch as you've written it works great for me.

Gaurav--
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