Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759876Ab1CDQWM (ORCPT ); Fri, 4 Mar 2011 11:22:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:61166 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759837Ab1CDQWL (ORCPT ); Fri, 4 Mar 2011 11:22:11 -0500 Date: Fri, 4 Mar 2011 17:13:21 +0100 From: Oleg Nesterov To: Denys Vlasenko Cc: Tejun Heo , Roland McGrath , jan.kratochvil@redhat.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org Subject: Re: [RFC] Proposal for ptrace improvements Message-ID: <20110304161321.GB23553@redhat.com> References: <20110301152457.GE26074@htj.dyndns.org> <20110303173422.GA27960@redhat.com> <20110303202246.GB32152@redhat.com> <20110304134126.GL20499@htj.dyndns.org> <20110304140745.GP20499@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Content-Length: 856 Lines: 29 On 03/04, Denys Vlasenko wrote: > > # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null' > exit_group(0) = ? > real 0m47.695s > user 0m3.965s > sys 0m29.047s > > strace with PTRACE_GETSIGINFO: > > # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null' > exit_group(0) = ? > real 0m51.958s > user 0m3.899s > sys 0m31.584s I am wondering how much ptrace_check_attach()->wait_task_inactive() contributes... it can sleep. And note that many ptrace requests do not really need this, PTRACE_GETSIGINFO in particular. Oleg. -- 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/