Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755183Ab3JDPQb (ORCPT ); Fri, 4 Oct 2013 11:16:31 -0400 Received: from merlin.infradead.org ([205.233.59.134]:49058 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755141Ab3JDPQ3 (ORCPT ); Fri, 4 Oct 2013 11:16:29 -0400 Date: Fri, 4 Oct 2013 17:16:18 +0200 From: Peter Zijlstra To: Steven Rostedt Cc: Yuanhan Liu , mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, linux-tip-commits@vger.kernel.org, Fengguang Wu , Huang Ying , lkp@linux.intel.com Subject: Re: [PATCH] ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHED Message-ID: <20131004151618.GO3081@twins.programming.kicks-ass.net> References: <20130927091427.GE24743@yliu-dev.sh.intel.com> <20130927152908.GE15690@laptop.programming.kicks-ass.net> <20131004080909.GP26785@twins.programming.kicks-ass.net> <20131004105342.20c00a41@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131004105342.20c00a41@gandalf.local.home> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2144 Lines: 48 On Fri, Oct 04, 2013 at 10:53:42AM -0400, Steven Rostedt wrote: > On Fri, 4 Oct 2013 10:09:09 +0200 > Peter Zijlstra wrote: > > > On Fri, Sep 27, 2013 at 05:29:08PM +0200, Peter Zijlstra wrote: > > > Subject: ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHED > > > From: Peter Zijlstra > > > Date: Fri Sep 27 17:11:00 CEST 2013 > > > > > > Since we now have two need_resched states; trace the two so we can > > > observe discrepancies. > > > > > > Cc: Steven Rostedt > > > Signed-off-by: Peter Zijlstra > > > > Steve, if you're done conferencing.. any objections? > > > > Taking a quick look, my only objection so far is that the change log is > rather flimsy. What are the two states and what are their dependencies? > > In other words, what does these flags in the trace actually mean? > Probably need to add comments in the code and/or update the > Documentation section Ah, you missed the preemption series? 1a338ac32ca6 sched, x86: Optimize the preempt_schedule() call c2daa3bed53a sched, x86: Provide a per-cpu preempt_count implementation a233f1120c37 sched: Prepare for per-cpu preempt_count bdb438065890 sched: Extract the basic add/sub preempt_count modifiers 01028747559a sched: Create more preempt_count accessors a787870924db sched, arch: Create asm/preempt.h f27dde8deef3 sched: Add NEED_RESCHED to the preempt_count 4a2b4b222743 sched: Introduce preempt_count accessor functions ea8117478918 sched, idle: Fix the idle polling state logic 315039862646 sched: Remove {set,clear}_need_resched b021fe3e2509 sched, rcu: Make RCU use resched_cpu() 0c44c2d0f459 x86: Use asm goto to implement better modify_and_test() functions preempt_count now includes a NEED_RESCHED and this patch shows which is set: N both PREEMPT_NEED_RESCHED and TIF_NEED_RESCHED, n for TIF only and p for preempt only. -- 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/