Mark Kirkwood <mark.kirkwood@catalyst.net.nz> wrote:
> On 11/07/14 20:22, Andres Freund wrote:
>> So, the majority of the time is spent in numa page migration.
>> Can you disable numa_balancing? I'm not sure if your kernel
>> version does that at runtime or whether you need to reboot.
>> The kernel.numa_balancing sysctl might work. Otherwise you
>> probably need to boot with numa_balancing=0.
>>
>> It'd also be worthwhile to test this with numactl --interleave.
>
> That was my feeling too - but I had no idea what the magic switch
> was to tame it (appears to be in 3.13 kernels), will experiment
> and report back. Thanks again!
It might be worth a test using a cpuset to interleave OS cache and
the NUMA patch I submitted to the current CF to see whether this is
getting into territory where the patch makes a bigger difference.
I would expect it to do much better than using numactl --interleave
because work_mem and other process-local memory would be allocated
in "near" memory for each process.
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