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=-7.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 78CC5C43603 for ; Fri, 20 Dec 2019 23:32:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D2DF2146E for ; Fri, 20 Dec 2019 23:32:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="N3O+SExt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726648AbfLTXcD (ORCPT ); Fri, 20 Dec 2019 18:32:03 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:39244 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726470AbfLTXcD (ORCPT ); Fri, 20 Dec 2019 18:32:03 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576884721; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0I7tRlX0mVn5vk+VIzw+jv3j0MYY94luXenim5wV+0c=; b=N3O+SExt9BtpKtb/xwGIbcpz8/QldPWCUI52ykiK1wRGh/fNCcj765Qn2tVbjUpaEk08L6 dO00d2jqUn7GdA4any5UQt3mUYLr2GDsgar2zyXcSNVghNAefuVSRvpqYpNLqISyFlLvAe aR78w5yiddSxRaVbK31h6fZ4SJVXnFI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-97-Ht9J4ufjPFWj1zKeZR5AqA-1; Fri, 20 Dec 2019 18:31:55 -0500 X-MC-Unique: Ht9J4ufjPFWj1zKeZR5AqA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 12FDB1856A60; Fri, 20 Dec 2019 23:31:53 +0000 (UTC) Received: from ming.t460p (ovpn-8-19.pek2.redhat.com [10.72.8.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C484A5D9CA; Fri, 20 Dec 2019 23:31:43 +0000 (UTC) Date: Sat, 21 Dec 2019 07:31:38 +0800 From: Ming Lei To: John Garry Cc: Marc Zyngier , tglx@linutronix.de, "chenxiang (M)" , bigeasy@linutronix.de, linux-kernel@vger.kernel.org, hare@suse.com, hch@lst.de, axboe@kernel.dk, bvanassche@acm.org, peterz@infradead.org, mingo@redhat.com Subject: Re: [PATCH RFC 1/1] genirq: Make threaded handler use irq affinity for managed interrupt Message-ID: <20191220233138.GB12403@ming.t460p> References: <20191214135641.5a817512@why> <7db89b97-1b9e-8dd1-684a-3eef1b1af244@huawei.com> <50d9ba606e1e3ee1665a0328ffac67ac@www.loen.fr> <68058fd28c939b8e065524715494de95@www.loen.fr> <687cbcc4-89d9-63ea-a246-ce2abaae501a@huawei.com> <0fd543f8ffd90f90deb691aea1c275b4@www.loen.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 20, 2019 at 03:38:24PM +0000, John Garry wrote: > > > We've got some more results and it looks promising. > > > > > > So with your patch we get a performance boost of 3180.1K -> 3294.9K > > > IOPS in the D06 SAS env. Then when we change the driver to use > > > threaded interrupt handler (mainline currently uses tasklet), we get a > > > boost again up to 3415K IOPS. > > > > > > Now this is essentially the same figure we had with using threaded > > > handler + the gen irq change in spreading the handler CPU affinity. We > > > did also test your patch + gen irq change and got a performance drop, > > > to 3347K IOPS. > > > > > > So tentatively I'd say your patch may be all we need. > > > > OK. > > > > > FYI, here is how the effective affinity is looking for both SAS > > > controllers with your patch: > > > > > > 74:02.0 > > > irq 81, cpu list 24-29, effective list 24 cq > > > irq 82, cpu list 30-35, effective list 30 cq > > > > Cool. > > > > [...] > > > > > As for your patch itself, I'm still concerned of possible regressions > > > if we don't apply this effective interrupt affinity spread policy to > > > only managed interrupts. > > > > I'll try and revise that as I post the patch, probably at some point > > between now and Christmas. I still think we should find a way to > > address this for the D05 SAS driver though, maybe by managing the > > affinity yourself in the driver. But this requires experimentation. > > I've already done something experimental for the driver to manage the > affinity, and performance is generally much better: > > https://github.com/hisilicon/kernel-dev/commit/e15bd404ed1086fed44da34ed3bd37a8433688a7 > > But I still think it's wise to only consider managed interrupts for now. > > > > > > JFYI, about NVMe CPU lockup issue, there are 2 works on going here: > > > > > > https://lore.kernel.org/linux-nvme/20191209175622.1964-1-kbusch@kernel.org/T/#t > > > > > > > > > https://lore.kernel.org/linux-block/20191218071942.22336-1-ming.lei@redhat.com/T/#t > > > > > > > I've also managed to trigger some of them now that I have access to > > a decent box with nvme storage. > > I only have 2x NVMe SSDs when this occurs - I should not be hitting this... > > Out of curiosity, have you tried > > with the SMMU disabled? I'm wondering whether we hit some livelock > > condition on unmapping buffers... > > No, but I can give it a try. Doing that should lower the CPU usage, though, > so maybe masks the issue - probably not. Lots of CPU lockup can is performance issue if there isn't obvious bug. I am wondering if you may explain it a bit why enabling SMMU may save CPU a it? Thanks, Ming