From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751579AbaJECXR (ORCPT ); Sat, 4 Oct 2014 22:23:17 -0400 Received: from mail-qc0-f172.google.com ([209.85.216.172]:63181 "EHLO mail-qc0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751448AbaJECXO (ORCPT ); Sat, 4 Oct 2014 22:23:14 -0400 Date: Sat, 4 Oct 2014 22:23:11 -0400 From: Tejun Heo To: Alexander Gordeev Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org Subject: Re: [PATCH RESEND v3 5/6] AHCI: Optimize single IRQ interrupt processing Message-ID: <20141005022311.GD8549@htj.dyndns.org> References: <20140923205710.GB17332@mtj.dyndns.org> <20140924104213.GA2695@agordeev.usersys.redhat.com> <20140924130444.GA16555@htj.dyndns.org> <20140924140844.GB2695@agordeev.usersys.redhat.com> <20140924143913.GH16555@htj.dyndns.org> <20141001153114.GE8971@agordeev.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141001153114.GE8971@agordeev.usersys.redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey, Alexander. On Wed, Oct 01, 2014 at 04:31:15PM +0100, Alexander Gordeev wrote: > As of your concern wrt threaded handler invocation overhead - I am > not quite sure here, but if SCHED_FIFO policy (the handler runs with) > makes the difference? Anyway, as said above the overall IO does not > suffer. Hmmm.... so, AFAICS, there's no real pros or cons of going either way, right? The only thing which could be different is possibly slightly lower latency in servicing other IRQs or RT tasks on the same CPU but given that the ahci IRQ handler already doesn't do anything which takes time, I'm doubtful whether that'd be anything measureable. I just don't get why ahci bothers with threaded irq, MMSI or not. Thanks. -- tejun