Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753356Ab2BUBja (ORCPT ); Mon, 20 Feb 2012 20:39:30 -0500 Received: from terminus.zytor.com ([198.137.202.10]:39409 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752624Ab2BUBj3 (ORCPT ); Mon, 20 Feb 2012 20:39:29 -0500 References: <1328888091-9692-1-git-send-email-konrad.wilk@oracle.com> <1329786103.25686.48.camel@gandalf.stny.rr.com> User-Agent: K-9 Mail for Android In-Reply-To: <1329786103.25686.48.camel@gandalf.stny.rr.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH] x86 fixes for 3.3 impacting distros (v1). From: "H. Peter Anvin" Date: Mon, 20 Feb 2012 17:38:52 -0800 To: Steven Rostedt , Konrad Rzeszutek Wilk CC: tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com Message-ID: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1253 Lines: 33 Odd... given that that is the NOP recommended by AMD. Steven Rostedt wrote: >On Fri, 2012-02-10 at 10:34 -0500, Konrad Rzeszutek Wilk wrote: >> 66 66 66 90 data32 data32 xchg %ax,%ax >> >> [the 66 66 .. is 'nop']. Looks good right? Well, it does work very >well on Intel >> (used an i3 2100), but on AMD A8-3850 it hits a performance wall - >that I found out >> is a result of CONFIG_FUNCTION_TRACER (too many nops??) being >compiled in (but the tracer >> is set to the default 'nop'). If I disable that specific config >option the numbers >> are the same as the baseline (with CONFIG_FUNCTION_TRACER disabled) >on the AMD box. >> Interestingly enough I only see these on AMD machines - not on the >Intel ones. > >All paravirt ops should be labeled with "notrace" so that function >tracer does not trace those functions. Have you annotated your new >paravirt ops with notrace? > >-- Steve -- Sent from my mobile phone. Please excuse my brevity and lack of formatting. -- 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/