From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCHSET 8/9] prep for hotplug support Date: Thu, 27 Apr 2006 06:36:55 -0400 Message-ID: <44509EC7.70807@pobox.com> References: <11447643813451-git-send-email-htejun@gmail.com> <44508D6A.3050200@pobox.com> <44509C98.80301@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:14246 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S965086AbWD0KhF (ORCPT ); Thu, 27 Apr 2006 06:37:05 -0400 In-Reply-To: <44509C98.80301@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: alan@lxorguk.ukuu.org.uk, axboe@suse.de, albertcc@tw.ibm.com, lkosewsk@gmail.com, linux-ide@vger.kernel.org Tejun Heo wrote: > Yeah, Forrest pointed out the same thing and I've converted hotplug_wq > to single threaded variant, which should be enough for SCSI hotplugging. > For ata_wq, I think it's wiser to keep it multi-threaded for the time > being. Maybe what should be done is to allocate a single threaded > workqueue per host_set. One thread per host_set would suck for any situation where that's doing ATAPI or PIO tasks. Would love to find a good metric... > $BIGNUM CPU boxes tend to have $BIGNUM GB of memories, so multithreaded > wq might not be that critical resource-wise. But, still, inefficient That's a bad assumption on modern machines. Think of a single 16-core, 8-thread SPARC Niagara CPU, for example :) Jeff