[LLVMdev] Recent compile time performance regressions

[Yi Kong]

On 1 August 2014 21:47, Yi Kong <kongy.dev at gmail.com> wrote:
> On 1 August 2014 21:33, Chandler Carruth <chandlerc at google.com> wrote:
>>> Note, this patch is actually the smaller culprit, around 209801 there is
>>> another performance regression, but I have no idea if/where this is coming
>>> from or if this for some reason is a false positive.
>>
>>
>> I'm having to question the results on this bot. The range of commits which
>> cause the larger compile time regression is 209797 - 209799... But those
>> commits are totally innocuous. The closest to a something that could go
>> poorly would be r209798, but that commit doesn't seem plausible for a huge
>> slowdown.
>>
>> I wonder if there is something weird going on with the bot...
>
> 209797-209799 regression is false positive, due to reverting perf back
> to original timeit tool.(r209797)

I misread my own commit message.:(
It's turning perf back on.

>
> However the multithreading stuff is real regression and I'm able to
> reproduce same regression on my local build bots.
>
> -Yi