From nobody Thu Apr 16 03:45:59 2026 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 788D3C43217 for ; Thu, 24 Nov 2022 03:45:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229727AbiKXDpZ (ORCPT ); Wed, 23 Nov 2022 22:45:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229585AbiKXDpW (ORCPT ); Wed, 23 Nov 2022 22:45:22 -0500 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 388DCD1; Wed, 23 Nov 2022 19:45:21 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4NHkQz486yz4f3lGb; Thu, 24 Nov 2022 11:45:15 +0800 (CST) Received: from [10.174.176.73] (unknown [10.174.176.73]) by APP4 (Coremail) with SMTP id gCh0CgC329jM6H5jbEk5BA--.7917S3; Thu, 24 Nov 2022 11:45:18 +0800 (CST) To: kashyap.desai@broadcom.com, sumit.saxena@broadcom.com, shivasharan.srikanteshwara@broadcom.com, jejb@linux.ibm.com, martin.petersen@oracle.com, megaraidlinux.pdl@broadcom.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block , "yukuai (C)" , "zhangyi (F)" From: Yu Kuai Subject: Why is MEGASAS_SAS_QD set to 256? Message-ID: <1c4d66ca-fe1a-3d1a-d7f9-4981d2fc9eb1@huaweicloud.com> Date: Thu, 24 Nov 2022 11:45:16 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgC329jM6H5jbEk5BA--.7917S3 X-Coremail-Antispam: 1UD129KBjvdXoW7XF4DGF13KF1fXr18KF1DGFg_yoWkGFcEgr 43G3s2qw4FkrsaqrW7Kr1Yyr4jyF4jvayDCr1qgry7ursrZr13GryDur1UXF43tayv9FsI g3s8ur1ruwn3ZjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbIxYFVCjjxCrM7AC8VAFwI0_Gr0_Xr1l1xkIjI8I6I8E6xAIw20E Y4v20xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwV A0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcVCY1x02 67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I 0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40E x7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x 0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7I2V7IY0VAS 07AlzVAYIcxG8wCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c 02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_ GFylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7 CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6rW3Jr0E3s1lIxAIcVC2z280aVAF wI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa 7IU1zuWJUUUUU== X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8"; format="flowed" Hi, While upgrading kernel from 4.19 to 5.10, I found that fio 1 thread 4k sequential io performance is dropped(160Mib -> 100 Mib), root cause is that queue_depth is changed from 64 to 256. commit 6e73550670ed1c07779706bb6cf61b99c871fc42 scsi: megaraid_sas: Update optimal queue depth for SAS and NVMe devices diff --git a/drivers/scsi/megaraid/megaraid_sas.h=20 b/drivers/scsi/megaraid/megaraid_sas.h index bd8184072bed..ddfbe6f6667a 100644 --- a/drivers/scsi/megaraid/megaraid_sas.h +++ b/drivers/scsi/megaraid/megaraid_sas.h @@ -2233,9 +2233,9 @@ enum MR_PD_TYPE { /* JBOD Queue depth definitions */ #define MEGASAS_SATA_QD 32 -#define MEGASAS_SAS_QD 64 +#define MEGASAS_SAS_QD 256 #define MEGASAS_DEFAULT_PD_QD 64 -#define MEGASAS_NVME_QD 32 +#define MEGASAS_NVME_QD 64 And with the default nr_requests 256, 256 queue_depth will make the elevator has no effect, specifically io can't be merged in this test case. Hence it doesn't make sense to me to set default queue_depth to 256. Is there any reason why MEGASAS_SAS_QD is changed to 64? Thanks, Kuai