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Re: [PATCH] alternative hirate for builtin_expert


My change on the probability of builtin_expect does have an impact on
the partial inline (more outlined functions will get inline back to
the original function).
I think this triggers an existing issue.
Dehao will explain this in his coming email.

-Rong

On Fri, Oct 4, 2013 at 6:05 AM, Ramana Radhakrishnan <ramrad01@arm.com> wrote:
> On 10/02/13 23:49, Rong Xu wrote:
>>
>> Here is the new patch. Honaz: Could you take a look?
>>
>> Thanks,
>>
>> -Rong
>>
>> On Wed, Oct 2, 2013 at 2:31 PM, Jan Hubicka <hubicka@ucw.cz> wrote:
>>>>
>>>> Thanks for the suggestion. This is much cleaner than to use binary
>>>> parameter.
>>>>
>>>> Just want to make sure I understand it correctly about the orginal
>>>> hitrate:
>>>> you want to retire the hitrate in PRED_BUILTIN_EXPECT and always use
>>>> the one specified in the biniltin-expect-probability parameter.
>>>
>>>
>>> Yes.
>>>>
>>>>
>>>> Should I use 90% as the default? It's hard to fit current value 0.9996
>>>> in percent form.
>>>
>>>
>>> Yes, 90% seems fine.  The original value was set quite arbitrarily and no
>>> real
>>> performance study was made as far as I know except yours. I think users
>>> that
>>> are sure they use expect to gueard completely cold edges may just use
>>> 100%
>>> instead of 0.9996, so I would not worry much about the precision.
>>>
>>> Honza
>>>>
>>>>
>>>> -Rong
>>>>>
>>>>>
>>>>> OK with that change.
>>>>>
>>>>> Honza
>
>
>
> This broke arm-linux-gnueabihf building libstdc++-v3. I haven't dug further
> yet but still reducing the testcase.
>
> See
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58619
>
> for details.
>
> Can you please deal with this appropriately ?
>
> regards
> Ramana
>
>


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