Messages in this thread | | | Date | Wed, 26 Aug 2015 19:08:52 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH 0/3] timer: Improve itimers scalability |
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On 08/26, Jason Low wrote: > > Hi Andrew, > > On Tue, 2015-08-25 at 20:27 -0700, Andrew Morton wrote: > > On Tue, 25 Aug 2015 20:17:45 -0700 Jason Low <jason.low2@hp.com> wrote: > > > > > When running a database workload on a 16 socket machine, there were > > > scalability issues related to itimers. > > > > > > Commit 1018016c706f addressed the issue with the thread_group_cputimer > > > spinlock taking up a significant portion of total run time. > > > > > > This patch series address the other issue where a lot of time is spent > > > trying to acquire the sighand lock. It was found in some cases that > > > 200+ threads were simultaneously contending for the same sighand lock, > > > reducing throughput by more than 30%. > > > > Does this imply that the patchset increased the throughput of this > > workload by 30%? > > > > And is this test case realistic? If not, what are the benefits on a > > real-world workload? > > Yes, the test case with the database workload is realistic.
Can't resists, sorry... to me the very idea to use the process wide posix- cpu-timers on performance critical application doesn't look realistic ;)
However, I thinks the patches are fine.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
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