Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757870Ab2HIXy2 (ORCPT ); Thu, 9 Aug 2012 19:54:28 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:39225 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752045Ab2HIXy1 (ORCPT ); Thu, 9 Aug 2012 19:54:27 -0400 Message-ID: <50244D9A.2070000@gmail.com> Date: Thu, 09 Aug 2012 16:54:02 -0700 From: David Daney User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101027 Fedora/3.0.10-1.fc12 Thunderbird/3.0.10 MIME-Version: 1.0 To: "H. Peter Anvin" , Steven Rostedt CC: Mathieu Desnoyers , LKML , Linus Torvalds , Ingo Molnar , Thomas Gleixner , Peter Zijlstra , Masami Hiramatsu , Avi Kivity , Christoph Hellwig , Andrew Morton Subject: Re: [RFC][PATCH] tracepoints: Move the work out of line from hotpath sections References: <1344544823.6935.82.camel@gandalf.stny.rr.com> <20120809205053.GB15109@Krystal> <1344551131.6935.90.camel@gandalf.stny.rr.com> <502444CC.8030906@linux.intel.com> In-Reply-To: <502444CC.8030906@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1348 Lines: 33 On 08/09/2012 04:16 PM, H. Peter Anvin wrote: > On 08/09/2012 03:25 PM, Steven Rostedt wrote: >>> >>> It might be better to improve gcc to move really cold branches out of >>> line (really, really far away), and use the compiler to do this, rather >>> than to use an extra indirection that adds bloat and complexity to the >>> kernel. Oh, you mean like: -freorder-blocks-and-partition >> >> I think modifying gcc is something that can help more than tracing. But >> that's been a pipe dream for such a long time that I've started dreaming >> about winning a gold medal in the Olympics instead. Standing on the >> podium listening to the crowd chanting your name along with your country >> is more fun to dream about than seeing your unlikely code stop becoming >> hurdles for the CPU sprinters. >> > > At one point, maybe, but lately we have had a lot more traction from the > gcc developers, giving us features like __fentry__ and asm goto. > I don't claim that -freorder-blocks-and-partition is bug free, but I imagine that the GCC developers would be open to fixing any bugs found. David Daney -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/