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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B0C43C30653 for ; Thu, 4 Jul 2024 05:37:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=wLpoVjnf11dl/ji5LMAo8cROGGRdckh5OoGKDIRtODA=; b=ram+tbHvPzuNfxoiKhszn62lyP NBsJgi6eNsDyY0zGF2SQFld37XrihhRsAw+RbJxQcsSP79Nk1jR2GrzsbXu/6ZlSTrLZuJ5IcBYMu Ka7NiupAcnebCa6LNZv2JLpdUHvvADc3ChtfvuhBDLRbToshe0Va38OalF8zHcRXdkqozDIHkEUuC Q7nyHldHUHZlnqSz8ju816l62YWwSKr0gGXpEn5h/KtS1JbT4FRZ6djq9SBg5bomOPlv6vjfGwjFw eZV40JRJCa9a8qudxpdcOfaTmmtZGNP/VVuIWigPUXMljV29KdsUa7nsHBxzKS5ms0B2FVNRDGRHk rc+qpxdw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sPF9x-0000000CE95-14jD; Thu, 04 Jul 2024 05:37:33 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sPF9u-0000000CE79-1XgJ for linux-nvme@lists.infradead.org; Thu, 04 Jul 2024 05:37:31 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 3B28168AFE; Thu, 4 Jul 2024 07:37:26 +0200 (CEST) Date: Thu, 4 Jul 2024 07:37:25 +0200 From: Christoph Hellwig To: Sagi Grimberg Cc: Hannes Reinecke , Christoph Hellwig , Keith Busch , linux-nvme@lists.infradead.org Subject: Re: [PATCH 2/4] nvme-tcp: align I/O cpu with blk-mq mapping Message-ID: <20240704053725.GB19735@lst.de> References: <20240703135021.34143-1-hare@kernel.org> <20240703135021.34143-3-hare@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240703_223730_571467_060FF4DA X-CRM114-Status: GOOD ( 16.54 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Jul 03, 2024 at 05:19:39PM +0300, Sagi Grimberg wrote: > > > On 03/07/2024 16:50, Hannes Reinecke wrote: >> When 'wq_unbound' is selected we should select the >> the first CPU from a given blk-mq hctx mapping to queue >> the tcp workqueue item. With this we can instruct the >> workqueue code to keep the I/O affinity and avoid >> a performance penalty. > > wq_unbound is designed to keep io_cpu to be UNBOUND, my recollection > was the the person introducing it was trying to make the io_cpu always be > on a specific NUMA node, or a subset of cpus within a numa node. So he uses > that and tinkers with wq cpumask via sysfs. Honestly, I think we really should kill this unbound module paramter before it causes more harm.