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Re: [PATCH] gcc parallel make check
- From: Richard Biener <richard dot guenther at gmail dot com>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: Mike Stump <mikestump at comcast dot net>, VandeVondele Joost <joost dot vandevondele at mat dot ethz dot ch>, David Malcolm <dmalcolm at redhat dot com>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>, "fortran at gcc dot gnu dot org" <fortran at gcc dot gnu dot org>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, "libstdc++ at gcc dot gnu dot org" <libstdc++ at gcc dot gnu dot org>
- Date: Tue, 16 Sep 2014 11:48:05 +0200
- Subject: Re: [PATCH] gcc parallel make check
- Authentication-results: sourceware.org; auth=none
- References: <20140911075123 dot GN17454 at tucnak dot redhat dot com> <20140911080640 dot GP17454 at tucnak dot redhat dot com> <20140911145300 dot GR17454 at tucnak dot redhat dot com> <908103EDB4893A42920B21D3568BFD93150F876D at MBX23 dot d dot ethz dot ch> <908103EDB4893A42920B21D3568BFD93150FE8D2 at MBX13 dot d dot ethz dot ch> <20140912163241 dot GC17454 at tucnak dot redhat dot com> <305370A6-ACBC-4DD4-AF96-32B3503F3388 at comcast dot net> <20140915160549 dot GM17454 at tucnak dot redhat dot com> <64B425D3-EDE8-4F28-B815-F9D374730F7F at comcast dot net> <CAFiYyc2TpoHsCtXospY96S4=17kbBce-c8EcV1S5=b-hcbp-Vg at mail dot gmail dot com> <20140916092830 dot GV17454 at tucnak dot redhat dot com>
On Tue, Sep 16, 2014 at 11:28 AM, Jakub Jelinek <email@example.com> wrote:
> On Tue, Sep 16, 2014 at 11:20:37AM +0200, Richard Biener wrote:
>> > This confuses me, but, no matter. Isnât 8hrs time data? :-)
> It is, but not time(1) data, just wall clock computed from subtracting
> mtimes of my make check output log and make -j48 bootstrap log.
>> >> patch toplevel make -j48 -k check took:
>> >> real 40m21.984s
>> >> user 341m51.675s
>> >> sys 112m46.993s
>> >> and with the patch make -j48 -k check took:
>> >> real 32m22.066s
>> >> user 355m1.788s
>> >> sys 117m5.809s
>> > These numbers are useful to try and ensure the overhead (scaling factor) is reasonable, thanks.
>> A nice improvement indeed. The patched result is 15 times faster
>> than the serial unpatched run. So there is room for improvement
> Note, the box used was oldish AMD 16-core, no ht, box, haven't tried it on anything
Ah, I assumed -j48 testing means you have 48 cores. I usually test
with -j12 on my 6-core HT-enabled box. A factor 15 scaling for 16
CPUs is of course close to the best we can achieve.
> more parallel, also it was normal hard disk, etc. No idea whether anything
> from this is relevant to that though.
> Some CPU time goes into the expect processes, I can retry the build tonight
> and grab also time(1) info from make -k check to see the user/sys times for
> serial testing.