[LLVMdev] [cfe-dev] [3.6 Release] RC3 has been tagged

Jack Howarth
2015-02-18T16:39:06Z

On Wed, Feb 18, 2015 at 11:22 AM, Jack Howarth
<howarth.mailing.lists at gmail.com> wrote:
> On Wed, Feb 18, 2015 at 10:55 AM, Jack Howarth
> <howarth.mailing.lists at gmail.com> wrote:
>> I finally got around to testing this on a Bloomfield processor (Early
>> 2009 MacPro 2x2.66 GHz dual-quad core) and the regressions from
>> http://llvm.org/bugs/show_bug.cgi?id=22589 are even more severe. For
>> 10 runs of scimark2_1c built with "-O3 -march=native"...
>>
>> llvm 3.5.1   1204.16+/-2.66 Mflops
>> 3.6 branch   866.49+/-1.26 Mflops
>>
>
> The proposed patch mitigates the damage on Bloomfield...
>
> patched 3.6svn   1073.69+/-1.97
>
> so we are only regressing the benchmark 24% rather than 39% there.
>          Jack
>

This still all begs the question of what exact metrics exist for the
Q/A of llvm releases? IMHO, the bad PR from shoving out compiler
releases with severe performance regressions in the generated code far
outweighs a brief delay to triage these issues as much as possible.
         Jack

>
>> Do you seriously want to ship with a 39% performance regression in a
>> major benchmark?
>>               Jack
>>
>> On Wed, Feb 18, 2015 at 10:33 AM, Renato Golin <renato.golin at
linaro.org> wrote:
>>> On 18 February 2015 at 14:37, Hal Finkel <hfinkel at anl.gov>
wrote:
>>>> I think that, unfortunately, for the others, there's not
sufficient time to investigate before the release.
>>>
>>> This looks like a serious case for 3.6.1, not RC5.
>>>
>>> cheers,
>>> --renato
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