[llvm-dev] Buildbots timing out on full builds

Diana Picus via llvm-dev llvm-dev at lists.llvm.org
Thu May 25 08:11:46 PDT 2017


Hi Daniel,

I built r303542, then applied your patch and built again and it still takes
real    34m30.279s
user    84m36.553s
sys     0m58.372s

This is better than the 50m I saw before, but I think we should try to
make it a bit faster. Do you have any other ideas to make it work?

Thanks,
Diana


On 22 May 2017 at 11:22, Diana Picus <diana.picus at linaro.org> wrote:
> Hi Daniel,
>
> I did your experiment on a TK1 machine (same as the bots) and for r303258 I get:
> real    18m28.882s
> user    35m37.091s
> sys     0m44.726s
>
> and for r303259:
> real    50m52.048s
> user    88m25.473s
> sys     0m46.548s
>
> If I can help investigate, please let me know, otherwise we can just
> try your fixes and see how they affect compilation time.
>
> Thanks,
> Diana
>
> On 22 May 2017 at 10:49, Daniel Sanders <daniel_l_sanders at apple.com> wrote:
>> r303341 is the re-commit of the r303259 which tripled the number of rules
>> that can be imported into GlobalISel from SelectionDAG. A compile time
>> regression is to be expected but when I looked into it I found it was ~25s
>> on my machine for the whole incremental build rather than the ~12mins you
>> are seeing. I'll take another look.
>>
>> I'm aware of a couple easy improvements we could make to the way the
>> importer works. I was leaving them until we change it over to a state
>> machine but the most obvious is to group rules by their top-level gMIR
>> instruction. This would reduce the cost of the std::sort that handles the
>> rule priorities in generating the source file and will also make it simpler
>> for the compiler to compile it.
>>
>>
>> On 21 May 2017, at 11:16, Vitaly Buka <vitalybuka at google.com> wrote:
>>
>> It must be r303341, I commented on corresponding llvm-commits thread.
>>
>> On Fri, May 19, 2017 at 7:34 AM, Diana Picus via llvm-dev
>> <llvm-dev at lists.llvm.org> wrote:
>>>
>>> Ok, thanks. I'll try to do a bisect next week to see if I can find it.
>>>
>>> Cheers,
>>> Diana
>>>
>>> On 19 May 2017 at 16:29, Daniel Sanders <daniel_l_sanders at apple.com>
>>> wrote:
>>> >
>>> >> On 19 May 2017, at 14:54, Daniel Sanders via llvm-dev
>>> >> <llvm-dev at lists.llvm.org> wrote:
>>> >>
>>> >> r303259 will have increased compile-time since it tripled the number of
>>> >> importable
>>> >> SelectionDAG rules but a quick measurement building the affected file:
>>> >>    ninja
>>> >> lib/Target/<Target>/CMakeFiles/LLVM<Target>CodeGen.dir/<Target>InstructionSelector.cpp.o
>>> >> for both ARM and AArch64 didn't show a significant increase. I'll check
>>> >> whether
>>> >> it made a different to linking.
>>> >
>>> > I don't think it's r303259. Starting with a fully built r303259, then
>>> > updating to r303258 and running 'ninja' gives me:
>>> >         real    2m28.273s
>>> >         user    13m23.171s
>>> >         sys     0m47.725s
>>> > then updating to r303259 and running 'ninja' again gives me:
>>> >         real    2m19.052s
>>> >         user    13m38.802s
>>> >         sys     0m44.551s
>>> >
>>> >> sanitizer-x86_64-linux-fast also timed out after one of my commits this
>>> >> morning.
>>> >>
>>> >>> On 19 May 2017, at 14:14, Diana Picus <diana.picus at linaro.org> wrote:
>>> >>>
>>> >>> Hi,
>>> >>>
>>> >>> We've noticed that recently some of our bots (mostly
>>> >>> clang-cmake-armv7-a15 and clang-cmake-thumbv7-a15) started timing out
>>> >>> whenever someone commits a change to TableGen:
>>> >>>
>>> >>> r303418:
>>> >>> http://lab.llvm.org:8011/builders/clang-cmake-armv7-a15/builds/7268
>>> >>> r303346:
>>> >>> http://lab.llvm.org:8011/builders/clang-cmake-armv7-a15/builds/7242
>>> >>> r303341:
>>> >>> http://lab.llvm.org:8011/builders/clang-cmake-armv7-a15/builds/7239
>>> >>> r303259:
>>> >>> http://lab.llvm.org:8011/builders/clang-cmake-armv7-a15/builds/7198
>>> >>>
>>> >>> TableGen changes before that (I checked about 3-4 of them) don't have
>>> >>> this problem:
>>> >>> r303253:
>>> >>> http://lab.llvm.org:8011/builders/clang-cmake-armv7-a15/builds/7197
>>> >>>
>>> >>> That one in particular actually finishes the whole build in 635s,
>>> >>> which is only a bit over 50% of the timeout limit (1200s). So, between
>>> >>> r303253 and now, something happened that made full builds
>>> >>> significantly slower. Does anyone have any idea what that might have
>>> >>> been? Also, has anyone noticed this on other bots?
>>> >>>
>>> >>> Thanks,
>>> >>> Diana
>>> >>
>>> >> _______________________________________________
>>> >> LLVM Developers mailing list
>>> >> llvm-dev at lists.llvm.org
>>> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>> >
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>>
>>
>>


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