On Fri, 2015-10-16 at 09:12 +0200, Ingo Molnar wrote: > * Jason Low <jason....@hpe.com> wrote: > > > > > With this patch set (along with commit 1018016c706f mentioned above), > > > > the performance hit of itimers almost completely goes away on the > > > > 16 socket system. > > > > > > > > Jason Low (4): > > > > timer: Optimize fastpath_timer_check() > > > > timer: Check thread timers only when there are active thread timers > > > > timer: Convert cputimer->running to bool > > > > timer: Reduce unnecessary sighand lock contention > > > > > > > > include/linux/init_task.h | 3 +- > > > > include/linux/sched.h | 9 ++++-- > > > > kernel/fork.c | 2 +- > > > > kernel/time/posix-cpu-timers.c | 63 > > > > ++++++++++++++++++++++++++++----------- > > > > 4 files changed, 54 insertions(+), 23 deletions(-) > > > > > > Is there some itimers benchmark that can be used to measure the effects > > > of these > > > changes? > > > > Yes, we also wrote a micro benchmark which generates cache misses and > > measures > > the average cost of each cache miss (with itimers enabled). We used this > > while > > writing and testing patches, since it takes a bit longer to set up and run > > the > > database. > > Mind posting it, so that people can stick it into a new 'perf bench timer' > subcommand, and/or reproduce your results with it?
Yes, sure. At the moment, this micro benchmark is written in C++ and integrated with the database code. We can look into rewriting it into a more general program so that it can be included in perf. Thanks, Jason -- 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/
