Is this mean, that we can't use all of CPU's power with 3.12 kernel? On 12/11/13, Howard Chu <hyc(a)symas.com&gt; wrote: > > > -------- Original Message -------- > Subject: Linux kernel performance regressions > Date: Wed, 11 Dec 2013 04:33:06 -0800 > From: Howard Chu <hyc(a)symas.com&gt; > To: OpenLDAP-devel(a)openldap.org <OpenLDAP-devel(a)openldap.org&gt; > > 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/ > >