Date: Mon, 22 Apr 2013 09:29:29 -0700 From: Freddie Cash <fjwcash@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org>, Robert Waksmundzki <waksmundzki@gmail.com> Subject: Re: NUMA, cpuset and malloc Message-ID: <CAOjFWZ4inzabFpO4OH-8U%2B5PpXzxO1mVyCnig0T8ghgsx0PH%2BA@mail.gmail.com> In-Reply-To: <201304221132.08194.jhb@freebsd.org> References: <D2C5ECBF-1D71-4E58-93D8-E670CD55E27D@gmail.com> <201304221132.08194.jhb@freebsd.org>
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On Mon, Apr 22, 2013 at 8:32 AM, John Baldwin <jhb@freebsd.org> wrote: > On Saturday, April 20, 2013 6:43:26 pm Robert Waksmundzki wrote: > > On NUMA systems allocated memory is striped across local and non-local > banks > in order to have consistent performance in case the task is rescheduled to > a > different CPU socket. > > When a process is pinned to a single CPU socket with cpuset having the > memory allocator prefer local banks would probably improve performance. > Default system behavior would stay the same and the optimization would > only be > triggered on big multi socket systems when administrator used cpuset > (command > mostly used for performance optimization anyway). > > > > Is this something currently implemented in FreeBSD? Is this even a good > idea? > > You can get something sort of like this by enabling NUMA in your kernel > (9.0 > and later) and always pinning your processes with cpuset. (The simple NUMA > bits always allocate memory in the memory domain the current thread is > running in at the time of the fault.) > How does one enable NUMA? A "grep -i numa /usr/src/sys/conf/NOTES /usr/src/sys/amd64/conf/NOTES" turns up 0 hits for both 9-STABLE r248547 and 10-CURRENT (April 11, used svnup so no way to get the exact revision number, that I know of). Or, is it enabled automatically? -- Freddie Cash fjwcash@gmail.com
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