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=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 C9D65C33CA4 for ; Sat, 11 Jan 2020 12:08:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9FBC52084D for ; Sat, 11 Jan 2020 12:08:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="vWwD3l3v" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729656AbgAKMIY (ORCPT ); Sat, 11 Jan 2020 07:08:24 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:36139 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729126AbgAKMIX (ORCPT ); Sat, 11 Jan 2020 07:08:23 -0500 Received: by mail-wm1-f65.google.com with SMTP id p17so4720573wma.1; Sat, 11 Jan 2020 04:08:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Gtjh3mkRUNQhRLfkU3LSwvngpCN57b8JcnSgu0JgPt4=; b=vWwD3l3v4WIvc51UphwLC2wvJKEEMnIndL8BIv07ZYBlGItqdhngNdb8W+QkzzwuPJ czuSUW3E6MoHnRWWfNYcbXxksQ4OLjRuLO5bedZZsS7hTJocKohXwLZSMujdf7qUr3Vt bGNAtDX4du93LbTDcLHm2HWu1Ez8txAtG/Ecfu1PCA5aVlfezm78o/DEne5XkdjMYTNA leVJ5X7EFtrjpTSClmfDQiJTdv/Oqm4IMq/uQUTeuCvxocNAgLg8NVMuSp2COfQtl3ta c0qARR0D2f//i8MOWmpS3DP2Oksd6UppjcfXJuDunOW2qDH7ok8kyF8mv8R+E/AoPtPQ I9mA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Gtjh3mkRUNQhRLfkU3LSwvngpCN57b8JcnSgu0JgPt4=; b=PF+phO6qyuOCWVok091QSLJnzzZXgpyVw0ds5b2YZOJs88OCL4nHnKxTs0slNhpjab 16l5mhSs9bO4i8m12iBDKMM0ZnD0Qj7UFvLOhe01UX/xL1pt5iiX7TCF4GlkW+pMKtPt oxB2TTx09APhQTnVUcUmUQNVhNcLXDMjR7Yifr0b0mLL0bpzdXkX3bDpMdkJZ+NUyuqS H6lRTocywS+h413aP3t5rME3wh3FQIxutnnPPYqsdbg/ptQurnhgF/lQ4CvmPeLi1WdB Nu2ZIE/M832hRH5m2h2dJl7vzF6wZtvk0F75M6ZIvVflSCA6oK8u/TInwKI0PIF+gy07 Xa2w== X-Gm-Message-State: APjAAAUYz71gfmXP4Wk713H9DfA8XASAkusAkhOkcOGIRx5b+6fuEDUD MKBHzSv05EFdM7ya2qBGpkV7GSnXF4j9p3KPRco= X-Google-Smtp-Source: APXvYqyQ1k1E8gWMY4lUkgRf/8mPwzKsPlmBvNGLTcF344kRbD9XiwJnjctr6wE4a2g45bjuhC8BZmo+a3WpLrHT7cY= X-Received: by 2002:a05:600c:2215:: with SMTP id z21mr10139432wml.55.1578744501107; Sat, 11 Jan 2020 04:08:21 -0800 (PST) MIME-Version: 1.0 References: <1578730634-109961-1-git-send-email-longli@linuxonhyperv.com> In-Reply-To: <1578730634-109961-1-git-send-email-longli@linuxonhyperv.com> From: Ming Lei Date: Sat, 11 Jan 2020 20:08:09 +0800 Message-ID: Subject: Re: [PATCH] scsi: storvsc: Correctly set number of hardware queues for IDE disk To: longli@linuxonhyperv.com Cc: "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Sasha Levin , "James E.J. Bottomley" , "Martin K. Petersen" , linux-hyperv@vger.kernel.org, Linux SCSI List , Linux Kernel Mailing List , Long Li Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 11, 2020 at 4:17 PM wrote: > > From: Long Li > > Commit 0ed881027690 ("scsi: storvsc: setup 1:1 mapping between hardware queue and CPU queue") > introduced a regression for disks attached to IDE. For these disks the host VSP only offers > one VMBUS channel. Setting multiple queues can overload the VMBUS channel and result in > performance drop for high queue depth workload on system with large number of CPUs. > > Fix it by leaving the number of hardware queues to 1 (default value) for IDE > disks. > > Fixes: 0ed881027690 ("scsi: storvsc: setup 1:1 mapping between hardware queue and CPU queue") > Signed-off-by: Long Li > --- > drivers/scsi/storvsc_drv.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c > index f8faf8b3d965..992b28e40374 100644 > --- a/drivers/scsi/storvsc_drv.c > +++ b/drivers/scsi/storvsc_drv.c > @@ -1842,9 +1842,11 @@ static int storvsc_probe(struct hv_device *device, > */ > host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT); > /* > + * For non-IDE disks, the host supports multiple channels. > * Set the number of HW queues we are supporting. > */ > - host->nr_hw_queues = num_present_cpus(); > + if (dev_id->driver_data != IDE_GUID) > + host->nr_hw_queues = num_present_cpus(); > > /* > * Set the error handler work queue. > -- > 2.20.1 > Reviewed-by: Ming Lei -- Ming Lei