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 E6600EB64D7 for ; Wed, 21 Jun 2023 08:26:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230418AbjFUI06 (ORCPT ); Wed, 21 Jun 2023 04:26:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229840AbjFUI04 (ORCPT ); Wed, 21 Jun 2023 04:26:56 -0400 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E3A7DD for ; Wed, 21 Jun 2023 01:26:54 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4QmGnQ675vz4f3n6h for ; Wed, 21 Jun 2023 16:26:50 +0800 (CST) Received: from [10.174.176.73] (unknown [10.174.176.73]) by APP4 (Coremail) with SMTP id gCh0CgBnHbFKtJJkfP3DMA--.4360S3; Wed, 21 Jun 2023 16:26:51 +0800 (CST) Subject: Re: Unacceptably Poor RAID1 Performance with Many CPU Cores To: Xiao Ni , Yu Kuai Cc: Ali Gholami Rudi , linux-raid@vger.kernel.org, song@kernel.org, "yukuai (C)" References: <20231506112411@laper.mirepesht> <82d2e7c4-1029-ec7b-a8c5-5a6deebfae31@huaweicloud.com> <20231606091224@laper.mirepesht> <20231606110134@laper.mirepesht> <8b288984-396a-6093-bd1f-266303a8d2b6@huaweicloud.com> <20231606115113@laper.mirepesht> <1117f940-6c7f-5505-f962-a06e3227ef24@huaweicloud.com> <20231606122233@laper.mirepesht> <20231606152106@laper.mirepesht> From: Yu Kuai Message-ID: <2311bff8-232c-916b-98b6-7543bd48ecfa@huaweicloud.com> Date: Wed, 21 Jun 2023 16:26:50 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID: gCh0CgBnHbFKtJJkfP3DMA--.4360S3 X-Coremail-Antispam: 1UD129KBjvJXoW7Ww47CFy3Zr13CF1fXFykGrg_yoW8XrWrpF 4Yqa4akFs8WrWIv3Z2qr4UuF48twsrXr15JF4ktrWSy3ZFvF93Wa1jqrySkayUGF4DC34U Xa4vqwnxX3W5CFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkE14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvEwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc7I2V7IY0VAS07AlzVAY IcxG8wCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14 v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkG c2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6rWUJVWrZr1UMIIF0xvEx4A2jsIE14v26r1j 6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUZa9 -UUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org Hi, 在 2023/06/21 16:05, Xiao Ni 写道: > On Fri, Jun 16, 2023 at 8:27 PM Yu Kuai wrote: >> >> Hi, >> >> 在 2023/06/16 19:51, Ali Gholami Rudi 写道: >>> >> >> Thanks for testing! >> >>> Perf's output: >>> >>> + 93.79% 0.09% fio [kernel.kallsyms] [k] entry_SYSCALL_64_after_hwframe >>> + 92.89% 0.05% fio [kernel.kallsyms] [k] do_syscall_64 >>> + 86.59% 0.07% fio [kernel.kallsyms] [k] __x64_sys_io_submit >>> - 85.61% 0.10% fio [kernel.kallsyms] [k] io_submit_one >>> - 85.51% io_submit_one >>> - 47.98% aio_read >>> - 46.18% blkdev_read_iter >>> - 44.90% __blkdev_direct_IO_async >>> - 41.68% submit_bio_noacct_nocheck >>> - 41.50% __submit_bio >>> - 18.76% md_handle_request >>> - 18.71% raid10_make_request >>> - 18.54% raid10_read_request >>> 16.54% read_balance >> >> There is not any spin_lock in fast path anymore. Now, looks like >> main cost is raid10 io path now(read_balance looks worth >> investigation, 16.54% is too much), and for a real device with ms >> io latency, I think latency in io path may not matter. > > Hi Kuai > > Cool. And I noticed you mentioned 'fast path' in many places. What's > the meaning of 'fast path'? Does it mean the path that i/os are > submitting? Yes, and fast path means the case all resources is available and io can be submitted to device without blocking. There should be no spin_lock or atomic ops in fast path, otherwise io performance will be affected. Thanks, Kuai > > Regards > Xiao > > > . >