From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 358A5192D97 for ; Thu, 14 Aug 2025 07:54:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755158071; cv=none; b=erFgyENW98I2KdDPQ7/J6SE9V0qMVNZrtFckfMGwO4vAMHFVYhkZRk1H1rKvewEPbz0uoJ9Ck82S5GFQJvyWYGyFGJt0GBwmQkLCwRDMHHICJ7e8NWMA88yIWJEKyv/SEOZ19MrDLNamaEi1KGZxDrVN4wix5wVkUTGqhNBXzFU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755158071; c=relaxed/simple; bh=gFxsN1xHXuH4aYODzZvCn6y9twW0wvYlwEoeBLVoaNg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=I8A7/N+pTI23PN354TIp7P4EaOHp0+Lre85gEtbtsQBZAiKK8eLBSM9ZBvdinBhYaElWL02cYtrqX9KqBeM7z8qhlHE5rJSflxmglbQnjZcMzh/D3AOOcAgRs873ocr1TPkZYyJdGNjFNxQIasx2n99KQGC3JJIrog4qIA5bJXI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=SHZnmlxk; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SHZnmlxk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755158068; 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=gvCHjnpcSAUaN7gXzwggkNMvZ98WWP2pt/inhjEHLms=; b=SHZnmlxkLF07TrXjmvKcFrWrwiaUufSgExrzsNftLz1/Tpo6LLqGsYbbnNrwK3WfIkkXw0 rLioeEie951IUm4gI01/HIpWX3C2SEuIna1zjvJLRyL4nksmAihMqmnmpklxToQb/m4THM pVIf7zuMAL7mtefNBxQNhZdxAaYyi8s= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-27-bu6aYrPAMeysp_9OCXCHZA-1; Thu, 14 Aug 2025 03:54:24 -0400 X-MC-Unique: bu6aYrPAMeysp_9OCXCHZA-1 X-Mimecast-MFC-AGG-ID: bu6aYrPAMeysp_9OCXCHZA_1755158062 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5BA711800298; Thu, 14 Aug 2025 07:54:21 +0000 (UTC) Received: from fedora (unknown [10.72.116.148]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 805F019327C0; Thu, 14 Aug 2025 07:54:11 +0000 (UTC) Date: Thu, 14 Aug 2025 15:54:07 +0800 From: Ming Lei To: Yu Kuai Cc: axboe@kernel.dk, yukuai3@huawei.com, bvanassche@acm.org, nilay@linux.ibm.com, hare@suse.de, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, johnny.chenyi@huawei.com Subject: Re: [PATCH 00/16] blk-mq: introduce new queue attribute asyc_dpeth Message-ID: References: <20250814033522.770575-1-yukuai1@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250814033522.770575-1-yukuai1@huaweicloud.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 On Thu, Aug 14, 2025 at 11:35:06AM +0800, Yu Kuai wrote: > From: Yu Kuai > > Backgroud and motivation: > > At first, we test a performance regression from 5.10 to 6.6 in > downstream kernel(described in patch 13), the regression is related to > async_depth in mq-dealine. > > While trying to fix this regression, Bart suggests add a new attribute > to request_queue, and I think this is a good idea because all elevators > have similar logical, however only mq-deadline allow user to configure > async_depth. And this is patch 9-16, where the performance problem is > fixed in patch 13; > > Because async_depth is related to nr_requests, while reviewing related > code, patch 2-7 are cleanups and fixes to nr_reqeusts. > > I was planning to send this set for the next merge window, however, > during test I found the last block pr(6.17-rc1) introduce a regression > if nr_reqeusts grows, exit elevator will panic, and I fix this by > patch 1,8. Please split the patchset into two: - one is for fixing recent regression on updating 'nr_requests', so this can be merged to v6.17, and be backport easily for stable & downstream - another one is for improving IO performance related with async_depth. Thanks, Ming