From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754200Ab1K1US0 (ORCPT ); Mon, 28 Nov 2011 15:18:26 -0500 Received: from casper.infradead.org ([85.118.1.10]:60215 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753677Ab1K1USZ convert rfc822-to-8bit (ORCPT ); Mon, 28 Nov 2011 15:18:25 -0500 Message-ID: <1322511490.2921.175.camel@twins> Subject: Re: [PATCH 7/9] ftrace, perf: Add support to use function tracepoint in perf From: Peter Zijlstra To: Steven Rostedt Cc: Jiri Olsa , fweisbec@gmail.com, mingo@redhat.com, paulus@samba.org, acme@ghostprotocols.net, linux-kernel@vger.kernel.org Date: Mon, 28 Nov 2011 21:18:10 +0100 In-Reply-To: <1322511375.17003.25.camel@frodo> References: <1322417074-5834-1-git-send-email-jolsa@redhat.com> <1322417074-5834-8-git-send-email-jolsa@redhat.com> <1322510318.17003.14.camel@frodo> <1322510931.2921.170.camel@twins> <1322511002.2921.171.camel@twins> <1322511375.17003.25.camel@frodo> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.2.1- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2011-11-28 at 15:16 -0500, Steven Rostedt wrote: > On Mon, 2011-11-28 at 21:10 +0100, Peter Zijlstra wrote: > > > > Yeah, but still not something you want to do during context switches, > > > right? > > > > Also, that's x86, there's still archs that need stop_machine(), right? > > s390 may need it, but till we add a work around there too. > > But yeah, if this happens at context switch, then we want the fast > enable/disable that Jiri made. Right, so the way tracepoint->perf works currently is we enable the tracepoint when we create the event. The tracepoint handler runs a per-cpu hlist. perf then registers with the per-cpu hlist on context switch.