From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (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 E74661FC104; Wed, 11 Dec 2024 02:57:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733885879; cv=none; b=r6H3jXQx0Xl55EV+IeZyEhN7WXvBVECT1EotOLuDhEaS4VWXpDnslHb8QAAzXJXpPysmD7PGw3qhTHtYotdIK7xfUVTTBNSSYasKbE3IjJIcEAyEy8qLdNU7fDtmHipyL9waTG/1zAZMRhnrn1vWSHxilvjtu6t30yNdE7yiyws= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733885879; c=relaxed/simple; bh=xDNfLDPziQoE8u5MKueY1acAOA6xYihr0w/rQseo8SM=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=fZ88JTmvmz1OOio84OcvucTWd6ZsOt9Nmhw3TZbpeVJ2lSekSHF+OwSKgkLfmEnJNfymRB06tYtHX9TrBjMTdDjpcCTqwSo8OqICpvcEBj7JfRH3gm1LRYJuVaHGpkuWMY9t3nQfV6PxRlOkzynNzKG6jKMfvD+BZWg+/8vEDLM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4Y7Kyh44cSz4f3jYW; Wed, 11 Dec 2024 10:57:32 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id C905C1A06D7; Wed, 11 Dec 2024 10:57:51 +0800 (CST) Received: from [10.174.176.73] (unknown [10.174.176.73]) by APP4 (Coremail) with SMTP id gCh0CgB3noKt_1hnQ6UJEQ--.10836S3; Wed, 11 Dec 2024 10:57:51 +0800 (CST) Subject: Re: [PATCH RFC 1/3] block/mq-deadline: Revert "block/mq-deadline: Fix the tag reservation code" To: Zhiguo Niu , Bart Van Assche Cc: Yu Kuai , axboe@kernel.dk, akpm@linux-foundation.org, yang.yang@vivo.com, ming.lei@redhat.com, osandov@fb.com, paolo.valente@linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, "yukuai (C)" References: <20241209115522.3741093-1-yukuai1@huaweicloud.com> <20241209115522.3741093-2-yukuai1@huaweicloud.com> <6e384b29-50d2-64bd-0d08-fc0f086c1cbd@huaweicloud.com> <7081765f-28d7-f594-1221-6034b9e88899@huaweicloud.com> From: Yu Kuai Message-ID: <48ee35f1-dbbe-b4ff-2507-9c0e7bd4db0d@huaweicloud.com> Date: Wed, 11 Dec 2024 10:57:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID:gCh0CgB3noKt_1hnQ6UJEQ--.10836S3 X-Coremail-Antispam: 1UD129KBjvJXoW7KryxCFyruryxXF1kZrWDArb_yoW8tF1rp3 yUKF4YyrZ8Ja48uw48Zwsagr4Fqr4Sqr13Gwn0grW2k3s8GF1qqF1aq3Z8ur97urWfJw1j 9Fyqy345ZF1qy3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBF14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvEwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7CjxVA2Y2ka 0xkIwI1lc7I2V7IY0VAS07AlzVAYIcxG8wCY1x0262kKe7AKxVWUtVW8ZwCF04k20xvY0x 0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E 7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcV C0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF 04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7 CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUd-B_UUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ Hi, 在 2024/12/11 10:38, Zhiguo Niu 写道: > Bart Van Assche 于2024年12月11日周三 04:33写道： >> >> On 12/9/24 10:22 PM, Yu Kuai wrote: >>> First of all, are we in the agreement that it's not acceptable to >>> sacrifice performance in the default scenario just to make sure >>> functional correctness if async_depth is set to 1? >> >> How much does this affect performance? If this affects performance >> significantly I agree that this needs to be fixed. >> >>> If so, following are the options that I can think of to fix this: >>> >>> 1) make async_depth read-only, if 75% tags will hurt performance in some >>> cases, user can increase nr_requests to prevent it. >>> 2) refactor elevator sysfs api, remove eq->sysfs_lock and replace it >>> with q->sysfs_lock, so deadline_async_depth_store() will be protected >>> against changing hctxs, and min_shallow_depth can be updated here. >>> 3) other options? >> >> Another option is to remove the ability to configure async_depth. If it >> is too much trouble to get the implementation right without causing >> regressions for existing workloads, one possibility is to remove support >> for restricting the number of asynchronous requests in flight. > Hi Bart, > I think it is very useful to restrict asynchronous requests when IO > loading is very heavy by aysnc_depth. > the following is my androidbench experiment in android device(sched_tag=128): > 1. setting heavy IO > while true; do fio -directory=/data -direct=0 -rw=write -bs=64M > -size=1G -numjobs=5 -name=fiotest > 2. run androidbench and results： > orignial async_depth > async_depth=nr_requests*3/4 delta > seq read 33.176 216.49 > 183.314 > seq write 28.57 62.152 > 33.582 > radom read 1.518 1.648 > 0.13 > radom write 3.546 4.27 > 0.724 > and our customer also feedback there is optimization when they test > APP cold start and benchmark after tunning async_depth. So do you guys writing async_depth? Looks like you're using nr_requests*3/4. If this is the case, the above option 1) is still working for you guys. However, in this test, I think the lower async_depth is, the better result you'll get. Thanks, Kuai > thanks！ >> >> Thanks, >> >> Bart. >> > . >