Hi list, I was trying to check if updating to 2.6.37 on our openSUSE 11.3 nodes would bring any performance changes for our application (HPC CFD programs) and was surprised to see a big performance decrease on my test runs. Trying to follow this problem down I came to the following perl test line to show the differences. If I run the following perl line on the same hardware on openSUSE 11.3, with 2.6.34.7-0.5-default and with 2.6.37-6-default (from http://download.opensuse.org/repositories/Kernel:/stable/openSUSE_11.3/x86_6... ) I get VERY different results: On 2.6.34 it runs in about 10 secs. On 2.6.37 it takes at least 17 secs to run. Could someone else test this on another hardware? Please run a couple of times with 2.6.34 and then with 2.6.37. Do others also see this big differences? The system I am testing on is a dual Xeon X5650 @ 2.67 GHz (12 cores) with 24 GB memory. Please set $T to your number of cores. Perhaps you would also have to reduce the (1..9e6) if you have less than 2GB per core. time perl -e 'use threads; $T=12 ; foreach (1..$T) { $thr[$i++] = threads->create(sub { printf "I am thread %s\n", threads->tid(); foreach (1..9e6) { push(@a, sqrt(1234)/sin(1234)) } ; printf "thread %s finished.\n", threads->tid(); }); } foreach (0..$T-1) { $thr[$_]->join(); }' Many thanks for testing! Does anyone have an idea why this could be happening? Richard -- Richard Ems mail: Richard.Ems@Cape-Horn-Eng.com Cape Horn Engineering S.L. C/ Dr. J.J. Dómine 1, 5º piso 46011 Valencia Tel : +34 96 3242923 / Fax 924 http://www.cape-horn-eng.com -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org