From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753131AbaAPCd5 (ORCPT ); Wed, 15 Jan 2014 21:33:57 -0500 Received: from e34.co.us.ibm.com ([32.97.110.152]:41562 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753043AbaAPCdf (ORCPT ); Wed, 15 Jan 2014 21:33:35 -0500 Date: Wed, 15 Jan 2014 18:33:28 -0800 From: "Paul E. McKenney" To: Oleg Nesterov Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu Subject: Re: [PATCH tip/core/timers 4/4] timers: Reduce future __run_timers() latency for first add to empty list Message-ID: <20140116023328.GS10038@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20140115051939.GA31164@linux.vnet.ibm.com> <1389763248-31297-1-git-send-email-paulmck@linux.vnet.ibm.com> <1389763248-31297-4-git-send-email-paulmck@linux.vnet.ibm.com> <20140115172409.GD11499@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140115172409.GD11499@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14011602-1542-0000-0000-00000545DB93 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 15, 2014 at 06:24:09PM +0100, Oleg Nesterov wrote: > On 01/14, Paul E. McKenney wrote: > > > > @@ -749,6 +749,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, > > > > base = lock_timer_base(timer, &flags); > > > > + (void)catchup_timer_jiffies(base); > > Agreed, but perhaps it would be better to do this before > all_timers++ in internal_add_timer() ? Excellent point, changed. > This is funny, but I already have the same change for ->next_timer, > if we add this optimization perhaps that trivial patch makes sense > too. Yep, I queued your change in my series as well, thank you! Thanx, Paul