From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f70.google.com (mail-lf0-f70.google.com [209.85.215.70]) by kanga.kvack.org (Postfix) with ESMTP id D853D6B0033 for ; Fri, 24 Nov 2017 03:38:34 -0500 (EST) Received: by mail-lf0-f70.google.com with SMTP id g35so5235072lfi.0 for ; Fri, 24 Nov 2017 00:38:34 -0800 (PST) Received: from SELDSEGREL01.sonyericsson.com (seldsegrel01.sonyericsson.com. [37.139.156.29]) by mx.google.com with ESMTPS id w9si7197144lfd.192.2017.11.24.00.38.33 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Nov 2017 00:38:33 -0800 (PST) Subject: Re: [PATCH] Add slowpath enter/exit trace events References: <20171123104336.25855-1-peter.enderborg@sony.com> <20171123122530.ktsxgeakebfp3yep@dhcp22.suse.cz> <20171123133629.5sgmapfg7gix7pu3@techsingularity.net> <20171123140127.7z5z6awj2ti6lozh@dhcp22.suse.cz> From: peter enderborg Message-ID: Date: Fri, 24 Nov 2017 09:38:31 +0100 MIME-Version: 1.0 In-Reply-To: <20171123140127.7z5z6awj2ti6lozh@dhcp22.suse.cz> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Language: en-GB Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko , Mel Gorman Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Steven Rostedt , Ingo Molnar , Alex Deucher , "David S . Miller" , Harry Wentland , Greg Kroah-Hartman , Tony Cheng , Andrew Morton , Vlastimil Babka , Johannes Weiner , Pavel Tatashin On 11/23/2017 03:01 PM, Michal Hocko wrote: > I am not sure adding a probe on a production system will fly in many > cases. A static tracepoint would be much easier in that case. But I > agree there are other means to accomplish the same thing. My main point > was to have an easy out-of-the-box way to check latencies. But that is > not something I would really insist on. > In android tracefs (or part of it) is the way for the system to control to = what developers can access to the linux system on commercial devices.=C2=A0= So it is very much used on production systems, it is even=C2=A0 a requirem= ent from google to be certified as android.=C2=A0 Things like dmesg is not.= =C2=A0 However, this probe is at the moment not in that scope.=C2=A0 My point is that you need to condense the information as much as possible b= ut still be useful before making the effort to copy it to userspace.=C2=A0 = And=C2=A0 for this the trace-event are very useful for small systems since = the cost is very low for events where no one is listening. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org