Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755372AbbHZDRy (ORCPT ); Tue, 25 Aug 2015 23:17:54 -0400 Received: from g9t5009.houston.hp.com ([15.240.92.67]:32855 "EHLO g9t5009.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750920AbbHZDRx (ORCPT ); Tue, 25 Aug 2015 23:17:53 -0400 From: Jason Low To: Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Oleg Nesterov , "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, Frederic Weisbecker , Linus Torvalds , Davidlohr Bueso , Steven Rostedt , Andrew Morton , Terry Rudd , Rik van Riel , Scott J Norton , Jason Low Subject: [PATCH 0/3] timer: Improve itimers scalability Date: Tue, 25 Aug 2015 20:17:45 -0700 Message-Id: <1440559068-29680-1-git-send-email-jason.low2@hp.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1141 Lines: 29 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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/