[Dovecot] Ongoing performance issues with 2.0.x

Brandon Davidson brandond at uoregon.edu
Mon Nov 8 21:01:48 EET 2010


On 11/8/10 10:39 AM, "Stan Hoeppner" <stan at hardwarefreak.com> wrote:
> However, if CONFIG_HZ=1000 you're generating WAY too many interrupts/sec
> to the timer, ESPECIALLY on an 8 core machine.  This will exacerbate the
> high context switching problem.  On an 8 vCPU (and physical CPU) machine
> you should have CONFIG_HZ=100 or a tickless kernel.  You may get by
> using 250, but anything higher than that is trouble.

On modern kernels you can boot with "divider=10" to take the HZ from 1000
down to 100 at boot time - no rebuilding necessary.


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