[PATCH] gcc parallel make check

Jakub Jelinek jakub@redhat.com
Tue Sep 16 09:28:00 GMT 2014

On Tue, Sep 16, 2014 at 11:20:37AM +0200, Richard Biener wrote:
> > This confuses me, but, no matter.  Isn’t 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
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.


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