Messages in this thread | | | Date | Wed, 15 Jul 2015 13:28:00 +0100 | From | Ken Moffat <> | Subject | Re: make -jN (n>1) ineffective in 4.2.0-rc on AMD Phenom |
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On Tue, Jul 14, 2015 at 09:23:31PM -0500, Jeff Epler wrote: > GNU Make 4.1 has a problem that causes it to be unable to use the > desired level of parallelism. Two people have reported that reverting a > commit which changes from fork to vfork "fixes" it. (i'm one of them, > unfortunately posting as anonymous in the tracker). > > Hoewver, if you are also seeing the linux kernel version as relevant to > producing the problem, that's quite interesting, and the underlying > cause may be different. We reproduced the problem on a range of older > kernels, from 3.2 to 3.18. > > http://savannah.gnu.org/bugs/?44555 > > Jeff
Thanks, but I think this is a different problem, I was probably not clear : I specify make -j4 and make does indeed run 4 jobs, but it is only getting the equivalent of 1 CPU instead of 4. It is running 4 jobs, but on the equivalent of 1 processor (so this takes much longer than -j1).
The reason I think it is a different problem is that I upgraded to make-4.1 in November and everything has been fine until now.
With 'top' from procps-ng-3.3.10 the display can show how active each CPU is (indeed, I think that is the default) - on earlier versions of 'top' I think that the output was very different.
ĸen -- This one goes up to eleven!
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