Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755415AbXFDORn (ORCPT ); Mon, 4 Jun 2007 10:17:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752201AbXFDORg (ORCPT ); Mon, 4 Jun 2007 10:17:36 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:43576 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751736AbXFDORf (ORCPT ); Mon, 4 Jun 2007 10:17:35 -0400 Date: Mon, 4 Jun 2007 16:17:18 +0200 From: Ingo Molnar To: James Morris Cc: linux-kernel@vger.kernel.org, Andrew Morton , Stephen Smalley , James Carter , Paul Moore , Eric Paris Subject: Re: [bug] very high non-preempt latency in context_struct_compute_av() Message-ID: <20070604141718.GA29674@elte.hu> References: <20070604112745.GA26350@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1378 Lines: 36 * James Morris wrote: > > the latency is caused by a _very_ long loop in the SELinux code: > > > > sshd-4828 0.N.. 465894us : avtab_search_node (context_struct_compute_av) > > What do the 0DNs fields mean and what did you use to create this > trace? i used the latency tracer from -rt. Here's the meaning of the fields: _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / trace-it-4751 0D... 0us : __next_cpu (user_trace_start) it's very easy to interpret: it traces all the function calls the kernel executes, and puts the symbolic function name (and its parent function) into the trace, time ordered. So it's a proper execution trace. Normally you can ignore the 'DN' type of flags - what matters in this case is the observed 130 msecs latency and the functions that were called while that latency happened. Ingo - 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/