From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 28 Sep 2001 12:57:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 28 Sep 2001 12:57:30 -0400 Received: from [195.223.140.107] ([195.223.140.107]:16373 "EHLO athlon.random") by vger.kernel.org with ESMTP id ; Fri, 28 Sep 2001 12:57:25 -0400 Date: Fri, 28 Sep 2001 18:58:00 +0200 From: Andrea Arcangeli To: Ingo Molnar Cc: Alexey Kuznetsov , Linus Torvalds , linux-kernel@vger.kernel.org, Alan Cox , bcrl@redhat.com Subject: Re: [patch] softirq performance fixes, cleanups, 2.4.10. Message-ID: <20010928185800.M24922@athlon.random> In-Reply-To: <20010928183244.K24922@athlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ; from mingo@elte.hu on Fri, Sep 28, 2001 at 06:46:16PM +0200 X-GnuPG-Key-URL: http://e-mind.com/~andrea/aa.gnupg.asc X-PGP-Key-URL: http://e-mind.com/~andrea/aa.asc Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 28, 2001 at 06:46:16PM +0200, Ingo Molnar wrote: > > On Fri, 28 Sep 2001, Andrea Arcangeli wrote: > > > he's allowing to repeat the loop more than once to hide it, [...] > > it's not done to 'hide' it in any way. I removed the mask method because > it's redundant under the new scheme. What you are missing is a property provided by the old method. We have the NET_RX_SOFTIRQ that floods very heavily, so far so good. Then we have HI_SOFTIRQ, incidentally HI_SOFTIRQ from irq wants to be executed with very low latency, with your patch it _can_ be postpone to ksoftirqd processing just because there's the NET_RX_SOFTIRQ cpu hog in background. With the old method it was guaranteed that the HI_SOFTIRQ was executed with very low latency within the irq, no matter of the NET_RX_SOFTIRQ flood. So there _is_ a difference, and the multiple-loop will tend to "hide" the difference. Andrea