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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 20E7AC433B4 for ; Wed, 7 Apr 2021 00:48:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA69C6139B for ; Wed, 7 Apr 2021 00:48:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245505AbhDGAsg (ORCPT ); Tue, 6 Apr 2021 20:48:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:42233 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233073AbhDGAsg (ORCPT ); Tue, 6 Apr 2021 20:48:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1617756506; 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=MdPTRk091gcTZwqq9o0J9KQfKfYiBKRj+ZIXa/lpmYE=; b=NyWEIzwbfVaoPu/NSFno8PlDarkpUZ8rFDUH6m+5h8ZLz1sTJ9WqWG1zg5wsim/p9MQ6w7 /78esEU35VrJL3S3CoBPzx6KPHjuLcwL70Tz69OV6IKihM7aleRGuue4CQRbPeKsZgXgon GGGq4mOLDkNBPhprcURTinXbgggmgZU= 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-30-qUCCXJc8N-ewV-cm8HrGvw-1; Tue, 06 Apr 2021 20:48:25 -0400 X-MC-Unique: qUCCXJc8N-ewV-cm8HrGvw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 37D6883DD20; Wed, 7 Apr 2021 00:48:24 +0000 (UTC) Received: from T590 (ovpn-12-69.pek2.redhat.com [10.72.12.69]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CD3CF19D9D; Wed, 7 Apr 2021 00:48:17 +0000 (UTC) Date: Wed, 7 Apr 2021 08:48:13 +0800 From: Ming Lei To: John Garry Cc: Jens Axboe , linux-block@vger.kernel.org, Yanhui Ma , Hannes Reinecke Subject: Re: [PATCH] blk-mq: set default elevator as deadline in case of hctx shared tagset Message-ID: References: <20210406031933.767228-1-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 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Apr 06, 2021 at 11:25:08PM +0100, John Garry wrote: > On 06/04/2021 04:19, Ming Lei wrote: > > Hi Ming, > > > Yanhui found that write performance is degraded a lot after applying > > hctx shared tagset on one test machine with megaraid_sas. And turns out > > it is caused by none scheduler which becomes default elevator caused by > > hctx shared tagset patchset. > > > > Given more scsi HBAs will apply hctx shared tagset, and the similar > > performance exists for them too. > > > > So keep previous behavior by still using default mq-deadline for queues > > which apply hctx shared tagset, just like before. > > I think that there a some SCSI HBAs which have nr_hw_queues > 1 and don't > use shared sbitmap - do you think that they want want this as well (without > knowing it)? I don't know but none has been used for them since the beginning, so not an regression of shared tagset, but this one is really. Thanks, Ming