Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754898Ab0F2SRc (ORCPT ); Tue, 29 Jun 2010 14:17:32 -0400 Received: from hera.kernel.org ([140.211.167.34]:40158 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754354Ab0F2SRb (ORCPT ); Tue, 29 Jun 2010 14:17:31 -0400 Message-ID: <4C2A385B.3010909@kernel.org> Date: Tue, 29 Jun 2010 20:15:55 +0200 From: Tejun Heo User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100317 SUSE/3.0.4-1.1.1 Thunderbird/3.0.4 MIME-Version: 1.0 To: Arjan van de Ven CC: Frederic Weisbecker , torvalds@linux-foundation.org, mingo@elte.hu, linux-kernel@vger.kernel.org, jeff@garzik.org, akpm@linux-foundation.org, rusty@rustcorp.com.au, cl@linux-foundation.org, dhowells@redhat.com, oleg@redhat.com, axboe@kernel.dk, dwalker@codeaurora.org, stefanr@s5r6.in-berlin.de, florian@mickler.org, andi@firstfloor.org, mst@redhat.com, randy.dunlap@oracle.com, Arjan van de Ven Subject: Re: [PATCH 34/35] async: use workqueue for worker pool References: <1277759063-24607-1-git-send-email-tj@kernel.org> <1277759063-24607-35-git-send-email-tj@kernel.org> <20100628225513.GB10104@nowhere> <4C299FD8.7030904@kernel.org> <20100629121855.GA5318@nowhere> <4C2A1558.7060007@kernel.org> <20100629155228.GK5318@nowhere> <4C2A176F.1090101@kernel.org> <4C2A220B.8080006@linux.intel.com> <4C2A2688.1020206@kernel.org> <4C2A3652.7030806@linux.intel.com> In-Reply-To: <4C2A3652.7030806@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Tue, 29 Jun 2010 18:16:02 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1306 Lines: 33 Hello, Arjan. On 06/29/2010 08:07 PM, Arjan van de Ven wrote: > we might be talking past eachother. ;-) > > let me define an example that is simple so that we can get on the same page > > assume a system with "enough" cpus, say 32. > lets say we have 2 async tasks, that each do an mdelay(1000); (yes I > know stupid, but exagerating things makes things easier to talk about) That's the main point to discuss tho. If you exaggerate the use case out of proportion, you'll end up with something which in the end is useful only in the imagination and we'll be doing things just because we can. Creating full number of unbound threads might look like a good idea to extract maximum cpu parallelism if you exaggerate the use case like the above but with the current actual use case, it's not gonna buy us anything and might even cost us more via unnecessary thread creations. So, let's talk about whether it's _actually_ useful for the current use cases. If so, sure, let's do it that way. If not, there is no reason to go there, right? Thanks. -- tejun -- 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/