From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: benh performance problem From: Benjamin Herrenschmidt To: Mikolaj Krzewicki Cc: linuxppc-dev list In-Reply-To: <40221664.70208@lycos.nl> References: <401FE138.8080807@lycos.nl> <1075847083.17327.31.camel@gaston> <40221664.70208@lycos.nl> Content-Type: text/plain Message-Id: <1076044476.885.9.camel@gaston> Mime-Version: 1.0 Date: Fri, 06 Feb 2004 16:14:36 +1100 Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On Thu, 2004-02-05 at 21:09, Mikolaj Krzewicki wrote: > the benchmark i used shows a speedup back to the values i'm used to. > The benchmark itself is an octave script the execution time of which i > tested with different kernels under similar circumstances, so here are > the details: > > 2.6.1-benh1, HZ=1000: timing=36.5s > 2.6.1-benh1, HZ=100 : timing=32s > > this is with X running and a lot more processes(not running). > the weird thing is it executes slightly faster (on average) with > pbbuttonsd off. > The machine is g3 500 ibook, the octave script is: > > tic; > a = abs(randn(1500, 1500)/10); > b = a'; > c= a*b; > a = reshape(b, 750, 3000); > b = a'; > timing=toc; > > so lots of system calls and cache flushing is in order. > > Mikolaj. Well, I don't knwo what the above means, I don't talk that language anyway :) The fact that pbbuttons makes a difference makes me think the interrupt handling is taking way too much time on your setup, and pbbuttons is loading the machine with PMU interrupts... Not sure if I can fix any of this at this point without doing a major rewrite of the exception handling code, I suspect those CPUs don't like running in real mode and our exception handling happens mostly in that mode in ppc32... Ben. ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/