From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756365Ab0JOPDe (ORCPT ); Fri, 15 Oct 2010 11:03:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:6065 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755540Ab0JOPDd (ORCPT ); Fri, 15 Oct 2010 11:03:33 -0400 Date: Fri, 15 Oct 2010 11:02:56 -0400 From: Jason Baron To: Peter Zijlstra Cc: Ingo Molnar , Frederic Weisbecker , linux-kernel@vger.kernel.org, David Miller , Mike Galbraith , Steven Rostedt , "H. Peter Anvin" Subject: Re: [RFC][PATCH 7/7] perf: Optimize sw events Message-ID: <20101015150256.GB2822@redhat.com> References: <20101014203404.222133139@chello.nl> <20101014203625.609332490@chello.nl> <1287134043.29097.1331.camel@twins> <1287154627.29097.1524.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1287154627.29097.1524.camel@twins> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 15, 2010 at 04:57:07PM +0200, Peter Zijlstra wrote: > On Fri, 2010-10-15 at 11:16 +0200, Peter Zijlstra wrote: > > On Thu, 2010-10-14 at 22:34 +0200, Peter Zijlstra wrote: > > > > > Index: linux-2.6/include/linux/perf_event.h > > > =================================================================== > > > --- linux-2.6.orig/include/linux/perf_event.h > > > +++ linux-2.6/include/linux/perf_event.h > > > @@ -1013,15 +1013,17 @@ static inline void perf_fetch_caller_reg > > > static inline void > > > perf_sw_event(u32 event_id, u64 nr, int nmi, struct pt_regs *regs, u64 addr) > > > { > > > - if (atomic_read(&perf_swevent_enabled[event_id])) { > > > - struct pt_regs hot_regs; > > > + struct pt_regs hot_regs; > > > > > > - if (!regs) { > > > - perf_fetch_caller_regs(&hot_regs); > > > - regs = &hot_regs; > > > - } > > > - __perf_sw_event(event_id, nr, nmi, regs, addr); > > > + JUMP_LABEL(&perf_swevent_enabled[event_id], have_event); > > > + return; > > > + > > > +have_event: > > > + if (!regs) { > > > + perf_fetch_caller_regs(&hot_regs); > > > + regs = &hot_regs; > > > } > > > + __perf_sw_event(event_id, nr, nmi, regs, addr); > > > } > > > > > > > OK, so it appears I only compile tested this bit without jump_label > > support, with that bit added back this horribly fails to compile like: > > > > In file included from /usr/src/linux-2.6/arch/x86/mm/fault.c:13: > > /usr/src/linux-2.6/include/linux/perf_event.h: In function ‘perf_sw_event.clone.0’: > > /usr/src/linux-2.6/include/linux/perf_event.h:1018: warning: asm operand 0 probably doesn’t match constraints > > /usr/src/linux-2.6/include/linux/perf_event.h:1018: error: impossible constraint in ‘asm’ > > > > Ah, figured it out, it needs __attribute__((always_inline)), otherwise > we end up with multiple keys for one label, which will clealy not work. > ah...cool! that should work. ignore my other suggestions... thanks, -Jason