Maybe related to this bug/feature: http://ubuntuforums.org/showthread.php?t=2179879 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1188647
On 12/13/13, Aris Setyawan <[email protected]> wrote: > Is this mean, that we can't use all of CPU's power with 3.12 kernel? > > On 12/11/13, Howard Chu <[email protected]> wrote: >> >> >> -------- Original Message -------- >> Subject: Linux kernel performance regressions >> Date: Wed, 11 Dec 2013 04:33:06 -0800 >> From: Howard Chu <[email protected]> >> To: [email protected] <[email protected]> >> >> We upgraded from kernel 3.5 to 3.12.3 to update some of our benchmark >> numbers >> and hit some major performance regressions, mainly because the kernel is >> throttling processes that use too much CPU. This is definitely a kernel >> bug, >> as the throttle mechanism belongs to the realtime scheduler and none of >> the >> processes being affected had realtime priority when the throttle kicked >> in. >> >> I've posted a query to the linux kernel mailing list but haven't gotten >> any >> satisfactory answers yet. The same throttling behavior also occurs with >> 3.11.10, but there are no corresponding messages in the kernel log. >> >> The email thread is here >> http://lkml.indiana.edu/hypermail/linux/kernel/1312.1/02313.html >> >> A patch that may be related is described here >> http://lkml.org/lkml/2013/5/29/640 which explains part of the observed >> behavior, but not all of it (and indeed may be a red herring, unless it >> has >> some interaction with the realtime scheduler). >> >> There appear to be other serious networking related regressions in 3.12 >> as >> well. http://lkml.indiana.edu/hypermail/linux/kernel/1312.1/02588.html >> >> I recommend staying on 3.10 for production servers until this is sorted >> out. >> >> -- >> -- Howard Chu >> CTO, Symas Corp. http://www.symas.com >> Director, Highland Sun http://highlandsun.com/hyc/ >> Chief Architect, OpenLDAP http://www.openldap.org/project/ >> >> >
