Date: Thu, 15 Apr 2010 08:23:28 -0500 From: Adam Vande More <amvandemore@gmail.com> To: Andriy Gapon <avg@freebsd.org> Cc: alc@freebsd.org, Maho NAKATA <chat95@mac.com>, alan.l.cox@gmail.com, freebsd-stable@freebsd.org, als@modulus.org Subject: Re: How to reproduce: Re: Only 70% of theoretical peak performance on FreeBSD 8/amd64, Corei7 920 Message-ID: <r2g6201873e1004150623n4acf12a8xad78182b4a4789f4@mail.gmail.com> In-Reply-To: <4BC6D436.7060207@freebsd.org> References: <h2yca3526251004122230l909bc93ey916d7fe0dd24fd33@mail.gmail.com> <4BC402B7.5000400@modulus.org> <v2gca3526251004122322i709c523ct4f93bcf75a778a8e@mail.gmail.com> <20100414.082109.29593248145846106.chat95@mac.com> <4BC5DEB4.1090208@freebsd.org> <x2k6201873e1004140934z6f7518b9j72ffd9e1adc1ad49@mail.gmail.com> <m2y6201873e1004140945n855c8800we9baced2e293f270@mail.gmail.com> <4BC5F289.7020408@freebsd.org> <n2o6201873e1004141047t97d89cb0o2688fae1875eae08@mail.gmail.com> <4BC6D436.7060207@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, Apr 15, 2010 at 3:54 AM, Andriy Gapon <avg@freebsd.org> wrote: > This is a good point. > But on the other hand, it means that our scheduler doesn't do a perfect job > here. BTW, I use ULE. > My observation is that when a number of CPU-intensive long running > processes is > less than or equal to number of cores, then the processes tend to stay on > the > same cores for a long time. > But if the number of the processes is greater, then they seem to jump from > core > to core a lot. > But I am not sure what would be an optimal strategy for that case. If we > try to > keep some lucky processes on the same core, then cpu time might be shared > unfairly. Shuffling cores provides more fairness, but can hurt total > performance. > Is is possible to add a tunable to the scheduler for it's aggressiveness in switching cores? -- Adam Vande More
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?r2g6201873e1004150623n4acf12a8xad78182b4a4789f4>