Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758036Ab0GBJGa (ORCPT ); Fri, 2 Jul 2010 05:06:30 -0400 Received: from a.mx.secunet.com ([195.81.216.161]:42429 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757976Ab0GBJGZ (ORCPT ); Fri, 2 Jul 2010 05:06:25 -0400 Date: Fri, 2 Jul 2010 11:08:01 +0200 From: Steffen Klassert To: Dan Kruchinin Cc: LKML , Herbert Xu Subject: Re: [PATCH 2/2] pcrypt: sysfs interface Message-ID: <20100702090801.GG10072@secunet.com> References: <20100629203939.29a0b4ff@leibniz> <20100630124742.GD10072@secunet.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) X-OriginalArrivalTime: 02 Jul 2010 09:06:23.0567 (UTC) FILETIME=[D823D5F0:01CB19C5] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1553 Lines: 43 On Thu, Jul 01, 2010 at 06:28:34PM +0400, Dan Kruchinin wrote: > > > > These statistic counters add a lot of atomic operations to the fast-path. > > Would'nt it be better to have these statistics in a percpu manner? > > This would avoid the atomic operations and we would get some additional > > information on the distribution of the queued objects. > > > > If I understood you correctly the resulting sysfs hierarchy would look like > this one: > pcrypt/ > |- serial_cpumask > |- parallel_cpumask > |- w0/ > +--- parallel_objects > +--- serial_objects > +--- reorder_objects > |- w1/ > ... > |- wN/ > > right? If so I think it won't be very convenient to monitor summary number > of parallel, serial and reorder objects. Yes, I thought about something like this. You can still take the sum over the percpu objects when you output the statistics. > Anyway I think these atomic operations take very small time in comparison > with other operations in padata. So small that it can be ignored. I have a patch in queue that simplifies the serialization mechanism and reduces the accesses of foreign and global memory as much as possible in the parallel codepath. Adding atomic operations to global memory (just to collect statistics) to the parallel codepath would go in the opposite direction. Steffen -- 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/