[RFC] Decrease default timeout for libstdc++ tests to 6 minutes

Jonathan Wakely jwakely@redhat.com
Mon Nov 30 14:58:30 GMT 2020


On 27/11/20 21:17 +0100, Christophe Lyon via Libstdc++ wrote:
>On Fri, 27 Nov 2020 at 17:13, Jonathan Wakely via Gcc-patches
><gcc-patches@gcc.gnu.org> wrote:
>>
>> The default for the GCC testsuite is 300, i.e. 5 minutes, which is the
>> same as the DejaGnu default.
>>
>> Libstdc++ overrides this to 600, i.e. 10 minutes.
>>
>> This seems ridiculously long. If any test takes that long on modern
>> hardware, something is wrong. We've seen this a lot recently with
>> buggy tests, and waiting for them to FAIL is tedious.
>>
>> I've already made libstdc++.exp respect the user's setting in
>> ~/.dejagnurc or the global site.exp file. This means anybody testing
>> on slow simulators or old hardware can choose their own timeout.
>>
>> I've added dg-timeout-factor to the slowest std::regex tests and have
>> a patch to do it for the PSTL tests, which both take far too long to
>> compile. That means you can choose a sensible timeout appropriate for
>> most tests (e.g. 60 seconds) and not get spurious failures from the
>> few dozen tests which are just very slow.
>>
>> I'd like to change the default to 6 minutes. If that goes well, I'd
>> like to lower it even further.
>>
>> The main benefit of this will be that buggy tests which hang will get
>> killed sooner, so we waste less time waiting for the inevitable
>> timeout.
>>
>
>I think that's a good idea, I did have problems sometimes when
>many tests timed out, causing the whole 'make check' to be
>killed before completion by our compute farm management system.

Thanks for the feedback. I've pushed this patch now.

It's been tested on powercp64le-linux, x86_64-linux, aarch64-linux,
sparc-solaris and powerpc-aix. They were all fine with much lower
defaults (e.g. 120 seconds). Let's see how this goes for people
testing on older or less powerful hardware.


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