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%. Jason Low (3): timer: Optimize fastpath_timer_check() timer: Check thread timers only when there are active thread timers timer: Reduce unnecessary sighand lock contention include/linux/init_task.h | 1 + include/linux/sched.h | 3 ++ kernel/time/posix-cpu-timers.c | 44 +++++++++++++++++++++++++++------------ 3 files changed, 34 insertions(+), 14 deletions(-) -- 1.7.2.5 -- 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/
