On Wed, 2015-08-26 at 19:08 +0200, Oleg Nesterov wrote: > 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.l...@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 ;)
I will let Hideaki elaborate more regarding the issue at the application level. > However, I thinks the patches are fine. > > > Reviewed-by: Oleg Nesterov <o...@redhat.com> Thanks for reviewing! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
