From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757991Ab0EVTAW (ORCPT ); Sat, 22 May 2010 15:00:22 -0400 Received: from mail.skyhub.de ([78.46.96.112]:52705 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757916Ab0EVTAN (ORCPT ); Sat, 22 May 2010 15:00:13 -0400 From: Borislav Petkov To: Ingo Molnar , Frederic Weisbecker , Steven Rostedt , Peter Zijlstra , Arnaldo Carvalho de Melo , Lin Ming Cc: linux-kernel@vger.kernel.org, Borislav Petkov Subject: [RFC PATCH 0/2] perf: persistent events prototype Date: Sat, 22 May 2010 21:00:04 +0200 Message-Id: <1274554806-28216-1-git-send-email-bp@alien8.de> X-Mailer: git-send-email 1.7.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, here is my first stab at persistent events. And since it is a first one, there's no special tricks but simply all subsystems which init before perf and have declared static tracepoints, simply mark some of them as persistent and perf enables them when inits. I haven't tested this yet and will do so when I get to work next week but I'm sending it out now so that I can get your thoughts on this and whether this is an agreeable direction I'm taking. Couple of yet unresolved issues I see with this: * persistent events are enabled unconditionally on all cpus and while this makes sense for MCEs tracing, do we still want to be flexible here and supply a cpumask instead? * what happens if there's no consumer for the traced data, the easiest would be to do nothing and let it get truncated in the trace buffer with newer data overwriting the oldest sample? * what about other events, and most importantly, what about hw events for which we take a PMU and want to make them persistent at the same time and it so happens that after making a couple of events persistent, we run out of PMUs and make the perf tool almost useless since persistent events are hogging all the hardware resources? * btw, perf and ftrace really need to get married :) /me ducks now... Thanks.