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Re: Disable tracer by default for profile use (issue4428074)
2011/4/29 Sharad Singhai (ààà ààààà) <singhai@google.com>:
> On Thu, Apr 28, 2011 at 4:38 PM, Richard Guenther
> <richard.guenther@gmail.com> wrote:
>>
>> On Fri, Apr 29, 2011 at 1:34 AM, Xinliang David Li <davidxl@google.com>
>> wrote:
>> > Sharad can provide some some performance data -- we have seen up to 2%
>> > degradation to with tracer turned on for one of google's most
>> > important program. Perhaps Sharad can collect some SPEC numbers.
>> >
>> > I agree a better approach should be to fix the problem in tracer
>> > instead of turning it off in trunk.
>>
>> Esp. not turning it off for profile-use only where it should have the most
>> precise input.
>>
>
> Yes. As I explained, I am not proposing to turn -ftracer off in the trunk.
Ah, sorry for the confusion on my side. If you can back up the change
with SPEC performance numbers it's ok for trunk as well. But indeed
coverage of -ftracer will be zero then, and I wonder what it is useful
for if it doesn't even do good with FDO ...
Richard.
> After some tuning the pass should be improved.
> As of now, during the performance analysis of the internal benchmarks, I
> have seen up to 2% performance loss with -ftracer and hence turned it off
> during FDO.
> I would do SPEC performance numbers and send those out.
> Thanks,
> Sharad
>
>>
>> Richard.
>>
>> > David
>> >
>> >
>> > On Thu, Apr 28, 2011 at 4:23 PM, Richard Guenther
>> > <richard.guenther@gmail.com> wrote:
>> >> On Thu, Apr 28, 2011 at 8:53 PM, Diego Novillo <dnovillo@google.com>
>> >> wrote:
>> >>> On Thu, Apr 28, 2011 at 14:51, Sharad Singhai <singhai@google.com>
>> >>> wrote:
>> >>>> This patch disables -ftracer for profile use. Okay for google/main?
>> >>>
>> >>> Could you elaborate on why doing this is beneficial? ÂAre you
>> >>> proposing this for trunk as well?
>> >>
>> >> It indeed doesn't make sense to me at all.
>> >>
>> >> Richard.
>> >>
>> >>>> 2011-04-28 ÂSharad Singhai Â<singhai@google.com>
>> >>>>
>> >>>> Â Â Â ÂGoogle Ref 40087
>> >>>> Â Â Â Â* opts.c (common_handle_option): Disable -ftracer for profile
>> >>>> use.
>> >>>> Â Â Â Â* doc/invoke.texi: Update doc that -ftracer is no longer
>> >>>> enabled for FDO.
>> >>>
>> >>> OK.
>> >>>
>> >>>
>> >>> Diego.
>> >>>
>> >>
>> >
>
>