From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Srivatsa S. Bhat" Subject: Re: [PATCH] PM: trace events for suspend/resume Date: Fri, 23 May 2014 12:06:23 +0530 Message-ID: <537EEC67.9030909@linux.vnet.ibm.com> References: <20140519230226.GA14382@linux.intel.com> <2794431.xZpr01emRq@vostro.rjw.lan> <537E7756.1000503@linux.vnet.ibm.com> <1400798669.26671.12.camel@pippen.local.home> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from e28smtp08.in.ibm.com ([122.248.162.8]:33478 "EHLO e28smtp08.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751904AbaEWGhg (ORCPT ); Fri, 23 May 2014 02:37:36 -0400 Received: from /spool/local by e28smtp08.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 23 May 2014 12:07:33 +0530 Received: from d28relay05.in.ibm.com (d28relay05.in.ibm.com [9.184.220.62]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 653FF1258056 for ; Fri, 23 May 2014 12:06:39 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay05.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s4N6bfa09634168 for ; Fri, 23 May 2014 12:07:41 +0530 Received: from d28av04.in.ibm.com (localhost [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s4N6bTPB013198 for ; Fri, 23 May 2014 12:07:29 +0530 In-Reply-To: <1400798669.26671.12.camel@pippen.local.home> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Steven Rostedt Cc: "Rafael J. Wysocki" , todd.e.brandt@linux.intel.com, linux-pm@vger.kernel.org, rafael.j.wysocki@intel.com On 05/23/2014 04:14 AM, Steven Rostedt wrote: > On Fri, 2014-05-23 at 03:46 +0530, Srivatsa S. Bhat wrote: >> Hi Todd, >> >> This might be a silly question, but the suspend_enter() function invokes >> ftrace_stop() before suspending the machine, and restarts ftrace after >> resume. And your patch seems to instrument code further down (deeper) >> in the suspend/resume path (such as disable_nonboot_cpus() for example). >> Doesn't the ftrace stop/start pose any problem for this patch? > > ftrace_start/stop() only affects the function tracer and not the > tracepoints. Those will still be recorded. > Ah, thank you for the clarification. > Note, we have an invested interest in getting rid of > ftrace_stop/start(). I rather mark all the suspend code with notrace or > find another method to protect suspend from function tracing. The > ftrace_stop/start() was more of a big hammer approach and I had plans > for getting rid of it in the future. That future is approaching fast :-) > Ok.. :-) Regards, Srivatsa S. Bhat