Automatic PGO - Initial implementation (1/N)

[Diego Novillo]

On Wed, Sep 25, 2013 at 1:25 AM, Kostya Serebryany <kcc at google.com> wrote:
>
>
>
> On Wed, Sep 25, 2013 at 12:38 AM, Renato Golin <renato.golin at linaro.org>
> wrote:
>>
>> On 24 September 2013 19:38, Eric Christopher <echristo at gmail.com> wrote:
>>>
>>> -gline-tables-only (or -gmlt in gcc parlance). This will give you
>>> accurate call stack information for each sample. Or at least as
>>> accurate as I can get it.
>>
>>
>> FWIW, I'm using perf with "-O3 -g" and LLVM has retained the line
>> information quite well throughout all the inlining and optimizations that
>> happened.
>>
>> I assume it's easier to keep line information than variable location
>> ranges and types. The biggest problem is to separate the two emissions, I
>> guess, not the quality of the resulting information.
>
>
> We've been using  -gline-tables-only for a long time and are satisfied with
> the quality.
> It even gives use inlined frames (when we ask).

OK, I think that just having line number information should be enough.
 I take it that it would not be a problem if I forced
-gline-tables-only in the front end when -mauto-profile is used?


Thanks.  Diego.