From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753096AbaIXKd0 (ORCPT ); Wed, 24 Sep 2014 06:33:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48336 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751772AbaIXKdW (ORCPT ); Wed, 24 Sep 2014 06:33:22 -0400 Date: Wed, 24 Sep 2014 11:42:15 +0100 From: Alexander Gordeev To: Tejun Heo 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: <20140924104213.GA2695@agordeev.usersys.redhat.com> References: <20140923205710.GB17332@mtj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140923205710.GB17332@mtj.dyndns.org> 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 On Tue, Sep 23, 2014 at 04:57:10PM -0400, Tejun Heo wrote: > Hmmm... how does it affect single device operation tho? It does make > individual interrupt handling heavier, no? I think it is difficult to assess "individual interrupt handling", since it depends from both the hardware and device access pattern. On the system I use the results are rather counter-intuitive: ahci_thread_fn() does not show up in perf report at all, nor ahci_single_irq_intr(). While before the change ahci_single_irq_intr() reported 0.00%. But since the handling is split in two parts it is rather incorrect to apply the same metric to the threaded context. Obviously, the threaded handler is expected slowed down by other interrupts handlers, but the whole system should benefit from it, which is exactly the aim of this change. > -- > tejun -- Regards, Alexander Gordeev agordeev@redhat.com