From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 23 Sep 2002 09:16:33 +0200 From: Jens Axboe Subject: Re: 2.5.38-mm2 Message-ID: <20020923071633.GA15479@suse.de> References: <3D8E96AA.C2FA7D8@digeo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3D8E96AA.C2FA7D8@digeo.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: lkml , "linux-mm@kvack.org" List-ID: On Sun, Sep 22 2002, Andrew Morton wrote: > +read-latency.patch > > Fix the writer-starves-reader elevator problem. This is basically > the read_latency2 patch from -ac kernels. > > On IDE it provides a 100x improvement in read throughput when there > is heavy writeback happening. 40x on SCSI. You need to disable Ah interesting. I do still think that it is worth to investigate _why_ both elevator_linus and deadline does not prevent the read starvation. The read-latency is a hack, not a solution imo. > tagged command queueing on scsi - it appears to be quite stupidly > implemented. Ahem I think you are being excessively harsh, or maybe passing judgement on something you haven't even looked at. Did you consider that you _drive_ may be the broken component? Excessive turn-around times for request when using deep tcq is not unusual, by far. -- Jens Axboe -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/