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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67411CDB474 for ; Fri, 13 Oct 2023 02:03:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229448AbjJMCDF (ORCPT ); Thu, 12 Oct 2023 22:03:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229445AbjJMCDE (ORCPT ); Thu, 12 Oct 2023 22:03:04 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0908FD6 for ; Thu, 12 Oct 2023 19:02:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1697162534; 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=1BZTAWCLnjPY0yXHnQbDlEMs44wsXzwC+R4ev+Nup1M=; b=TbpbpULOPS4S4EtOqug4aBBnnGhBIMFNPDlyPi86hZe3oy0iNS0w4BkYjX/glegRt0Pt80 HeYwiB9PQxQcHyAxEWyqDHS014d3o8fCwG6m2KzMaApu14nhCHZXYkFLIFIl6wOzVXq31W hC7kkGnrmolllweSfVr+HfaKpFB4hZ8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-385-4u3xc-cXMd-J70mk6Nx6XQ-1; Thu, 12 Oct 2023 22:01:59 -0400 X-MC-Unique: 4u3xc-cXMd-J70mk6Nx6XQ-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0E9D988B7A6; Fri, 13 Oct 2023 02:01:59 +0000 (UTC) Received: from fedora (unknown [10.72.120.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8E997486F32; Fri, 13 Oct 2023 02:01:53 +0000 (UTC) Date: Fri, 13 Oct 2023 10:01:48 +0800 From: Ming Lei To: Tejun Heo Cc: Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Juri Lelli , Andrew Theurer , Joe Mario , Sebastian Jug , Frederic Weisbecker , ming.lei@redhat.com Subject: Re: [PATCH] blk-mq: add module parameter to not run block kworker on isolated CPUs Message-ID: References: <20231010142216.1114752-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi Tejun, On Thu, Oct 12, 2023 at 09:55:55AM -1000, Tejun Heo wrote: > Hello, > > On Wed, Oct 11, 2023 at 08:39:05AM +0800, Ming Lei wrote: > > I appreciate that any specific suggestions about dealing with isolated CPUs > > generically for bound WQ can be shared. > > Oh, all I meant was whether we can at least collect this into or at least > adjacent to the existing housekeeping / isolcpu parameters. Let's say > there's someone who really wants to isolated some CPUs, how would they find > out the different parameters if they're scattered across different > subsystems? AFAIK, the issue is reported on RH Openshift environment and it is real use case, some of CPUs are isolated for some dedicated tasks(such as network polling, ...) by passing "isolcpus=managed_irq nohz_full". But blk-mq still queue kworker on these isolated CPUs, and cause very long latency in nvme IO workloads. Joe should know the story much more then me. Thanks, Ming