Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752111AbaBRUSD (ORCPT ); Tue, 18 Feb 2014 15:18:03 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45840 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751802AbaBRUSA (ORCPT ); Tue, 18 Feb 2014 15:18:00 -0500 Message-ID: <1392754665.2165.33.camel@flatline.rdu.redhat.com> Subject: Re: [PATCH v3] audit: Turn off TIF_SYSCALL_AUDIT when there are no rules From: Eric Paris To: Andy Lutomirski Cc: linux-audit@redhat.com, linux-kernel@vger.kernel.org, Andi Kleen , Oleg Nesterov , Steve Grubb Date: Tue, 18 Feb 2014 15:17:45 -0500 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2014-02-08 at 13:06 -0800, Andy Lutomirski wrote: > This toggles TIF_SYSCALL_AUDIT as needed when rules change instead > of leaving it set whenever rules might be set in the future. This > reduces syscall latency from >60ns to closer to 40ns on my laptop. Al also politely reminded me it might be wise to get some perf data about where exactly we are spending out time. I don't know squat about perf, but Linus always tells me to do: perf record -g -e cycles:pp -F 25000 $YOURTEST perf report -s symbol (the "-s symbol" is so that you don't get separate data for the different processes that are part of the kernel build - you'll just want "general kernel data"), and on one of the kernel symbols just select it and do "Zoom into kernel DSO". You should see something like this: -- 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/