From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7B2BC433DF for ; Fri, 9 Oct 2020 15:01:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F6C3222E7 for ; Fri, 9 Oct 2020 15:01:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389109AbgJIPBo (ORCPT ); Fri, 9 Oct 2020 11:01:44 -0400 Received: from foss.arm.com ([217.140.110.172]:53114 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389099AbgJIPBo (ORCPT ); Fri, 9 Oct 2020 11:01:44 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 660361063; Fri, 9 Oct 2020 08:01:43 -0700 (PDT) Received: from e107158-lin.cambridge.arm.com (e107158-lin.cambridge.arm.com [10.1.195.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 300973F70D; Fri, 9 Oct 2020 08:01:42 -0700 (PDT) Date: Fri, 9 Oct 2020 16:01:39 +0100 From: Qais Yousef To: Frederic Weisbecker Cc: jun qian , Thomas Gleixner , peterz@infradead.org, will@kernel.org, luto@kernel.org, linux-kernel@vger.kernel.org, Yafang Shao , Uladzislau Rezki Subject: Re: [PATCH V7 4/4] softirq: Allow early break the softirq processing loop Message-ID: <20201009150139.vatmppe2e3cwtoof@e107158-lin.cambridge.arm.com> References: <20200915115609.85106-1-qianjun.kernel@gmail.com> <20200915115609.85106-5-qianjun.kernel@gmail.com> <878scz89tl.fsf@nanos.tec.linutronix.de> <20200925004207.GE19346@lenoir> <20200929114428.GA56480@lothringen> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200929114428.GA56480@lothringen> User-Agent: NeoMutt/20171215 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/29/20 13:44, Frederic Weisbecker wrote: > > that will delay the net_rx/tx softirq to process, Peter's branch > > maybe can slove > > the problem > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git core/softirq > > It's probably also the right time for me to resume on this patchset: > > https://lwn.net/Articles/779564/ > > In the long term this will allow us to have per vector threads that can be > individually triggered upon high loads, and even soft interruptible by > other vectors from irq_exit(). Also if several vectors are on high loads > at the same time, this leaves the balance decisions to the scheduler instead > of all these workarounds we scratch our heads on for several years now. > > Besides, I'm convinced that splitting the softirqs is something we want in > the long run anyway. So if I understood correctly we'll end up with a kthread for each softirq type that can be scheduled individually on any CPU following the 'normal' scheduler rules, correct? If I got it right, I like that. I certainly think having these softirqs as RT threads (like irq threads) makes a lot more sense. At least one would be able to use priorities to reason about when it's okay to preempt them or not. If I got it wrong, why we can't do that? Thanks -- Qais Yousef