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Re: [PATCH] Do not scale NPTL tests with available number of CPUs
- From: Florian Weimer <fweimer at redhat dot com>
- To: Zack Weinberg <zackw at panix dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Wed, 30 Aug 2017 16:32:39 +0200
- Subject: Re: [PATCH] Do not scale NPTL tests with available number of CPUs
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On 08/30/2017 04:21 PM, Zack Weinberg wrote:
> On Wed, Aug 30, 2017 at 10:08 AM, Adhemerval Zanella
> <adhemerval.zanella@linaro.org> wrote:
>> On 30/08/2017 09:44, Florian Weimer wrote:
>>> On very large multi-processor systems, creating hundreds of threads
>>> runs into a test time out. The tests do not seem to benefit from
>>> massive over-scheduling.
>>>
>>> 2017-08-30 Florian Weimer <fweimer@redhat.com>
>>>
>>> Do not scale NPTL tests with available number of CPUs.
>>> * nptl/tst-cond16.c (count): Sett to constant value of 8.
>
> This verb is spelled "set" in English, not "sett".
I fixed that before committing.
> Should it maybe be min(8, ncpus) instead of just 8?
I don't think that's worth the added complexity. Even on a UP system,
the overscheduling does not introduce a significant delay in thread
creation and termination.
$ time taskset 1 bash testrun.sh nptl/tst-cond16
real 0m20.005s
user 0m19.984s
sys 0m0.020s
Thanks,
Florian