Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759657Ab1CDOb6 (ORCPT ); Fri, 4 Mar 2011 09:31:58 -0500 Received: from mail-fx0-f46.google.com ([209.85.161.46]:40184 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759618Ab1CDOb4 convert rfc822-to-8bit (ORCPT ); Fri, 4 Mar 2011 09:31:56 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=pBASrH0khO26sfgOZIBeMpELaaJEtPGcrw5yORYrvRWQXBfwUzTaxUpGR0E5Tu/YKP Z0fcQoYxCKgQHplOTjQquhu2OUdI1VvWkN2yH1WTONXkVNkaUJKwM5i6C2bMoVMHpk9h q4nCj4pz4QkGr/lDYuQAGkzmwE/pvOjrSQvwM= MIME-Version: 1.0 In-Reply-To: <20110304140745.GP20499@htj.dyndns.org> References: <20110301152457.GE26074@htj.dyndns.org> <20110303173422.GA27960@redhat.com> <20110303202246.GB32152@redhat.com> <20110304134126.GL20499@htj.dyndns.org> <20110304140745.GP20499@htj.dyndns.org> From: Denys Vlasenko Date: Fri, 4 Mar 2011 15:31:15 +0100 Message-ID: Subject: Re: [RFC] Proposal for ptrace improvements To: Tejun Heo Cc: Oleg Nesterov , Roland McGrath , jan.kratochvil@redhat.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1738 Lines: 58 On Fri, Mar 4, 2011 at 3:07 PM, Tejun Heo wrote: > Hello, > > On Fri, Mar 04, 2011 at 02:59:32PM +0100, Denys Vlasenko wrote: >> I would rather speed strace up than slow it down further, even if >> slightly. > > The question to ask is at what cost? ?If mostly unnoticeable slow down > makes the API cleaner, I'll go that way. ?Everything is a tradeoff. # time sh -c 'ls -lR /usr/share >/dev/null' real 0m2.633s user 0m0.540s sys 0m2.047s strace without PTRACE_GETSIGINFO: # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null' exit_group(0) = ? real 0m47.023s user 0m3.843s sys 0m29.050s # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null' exit_group(0) = ? real 0m48.799s user 0m3.808s sys 0m29.736s # 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 # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null' exit_group(0) = ? real 0m53.773s user 0m3.920s sys 0m29.713s # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null' exit_group(0) = ? real 0m51.625s user 0m3.961s sys 0m30.970s -- vda -- 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/