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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 529A5C433E2 for ; Mon, 20 Jul 2020 07:24:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE55F207DF for ; Mon, 20 Jul 2020 07:23:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="c4C6aSft" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726486AbgGTHX7 (ORCPT ); Mon, 20 Jul 2020 03:23:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726254AbgGTHX7 (ORCPT ); Mon, 20 Jul 2020 03:23:59 -0400 Received: from mail-qk1-x743.google.com (mail-qk1-x743.google.com [IPv6:2607:f8b0:4864:20::743]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA35EC061794 for ; Mon, 20 Jul 2020 00:23:58 -0700 (PDT) Received: by mail-qk1-x743.google.com with SMTP id d14so2631182qke.13 for ; Mon, 20 Jul 2020 00:23:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=from:references:in-reply-to:mime-version:thread-index:date :message-id:subject:to:cc; bh=1ZdvEQtoQTsKklRiOdXXItC7m6E8GxiS/j8poJfLDnY=; b=c4C6aSfti0IzUz0ofptAt99y9cY5kbATBCWjB1eFadVNIVMywhilXgbAw10qSFeF1v rXSxtRLA8g+6n2WwPzEXmrsYvdTSKCi9jjCdWHFF8rt3uArMNsNoLRkrAMy4PxNc33Hc 3f8lIHdmfOj2U9XqSp8bGzIxD1rRPlKmIEWQk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:references:in-reply-to:mime-version :thread-index:date:message-id:subject:to:cc; bh=1ZdvEQtoQTsKklRiOdXXItC7m6E8GxiS/j8poJfLDnY=; b=cOlY9jP8Itg1mPwbHkBK9mA5bJ+49iCqe3FAPvQAfMtL9P3qFDWE9EO1f4CoNAfbut U6ZsLhdb3m+SLKCDTmArJ3+WiAU3GpZN1k91jZz53n5NVBLwBp8Ffh7mSB7hZkBrq0lF 4fBN8FAt/phbH59tmXbf/SB2daIWy7BW3IiYpy8Hi+5R8uLAHlmX7VY08D4g/dmbHxCZ lGo4/Okv3/Oz6HRUGnEYlFo3O0b5AbNpbBUbeuQT6R23ERUCC847utglGrtVR5OUF4qO LiM1nYI9DEdhJe1VTY/jFumOkut1uuakRD+p06oNRtMLig1RfzUiqwLtHmdYEi0fNlk0 sY1w== X-Gm-Message-State: AOAM533I9gxsqMz7oEr9dLm2RiiBFx7ts6Knh8/cr1+JJROfbuQeU+R5 1H5iJ9YrqLcq1y9tmuZWgeJoShV2FoL8JbXKSb9ILw== X-Google-Smtp-Source: ABdhPJwehSaPP8tkR31fqFSCdrhnoxs1mA1h5JvYNpb/U7dDFm+ZCEY+fJEURvlvM2QIxVYuJ1pLpKZkS33zdz74Ros= X-Received: by 2002:a37:d0e:: with SMTP id 14mr19177747qkn.27.1595229837769; Mon, 20 Jul 2020 00:23:57 -0700 (PDT) From: Kashyap Desai References: <1591810159-240929-1-git-send-email-john.garry@huawei.com> <1591810159-240929-11-git-send-email-john.garry@huawei.com> <92ba1829c9e822e4239a7cdfd94acbce@mail.gmail.com> <10d36c09-9d5b-92e9-23ac-ea1a2628e7d9@huawei.com> <0563e53f843c97de1a5a035fae892bf8@mail.gmail.com> <61299951-97dc-b2be-c66c-024dfbd3a1cb@huawei.com> <13d6b63e-3aa8-68fa-29ab-a4c202024280@huawei.com> <34a832717fef4702b143ea21aa12b79e@mail.gmail.com> <1dcf2bb9-142c-7bb8-9207-5a1b792eb3f9@huawei.com> 2314e216d1d546e2072d09bd111b4b58@mail.gmail.com In-Reply-To: 2314e216d1d546e2072d09bd111b4b58@mail.gmail.com MIME-Version: 1.0 X-Mailer: Microsoft Outlook 15.0 Thread-Index: AQBVjmvxAE7FMYb7GtMRWGcwtMcECgFIs823Ad7lfqMBmFaE1AGZowweAlKrFcUB/hGY5AG4aoXNAvsHUMYCeW9VQwH6WrIOAzKzW+yrWLxrUIAAzqMQ Date: Mon, 20 Jul 2020 12:53:55 +0530 Message-ID: Subject: RE: [PATCH RFC v7 10/12] megaraid_sas: switch fusion adapters to MQ To: John Garry , axboe@kernel.dk, jejb@linux.ibm.com, martin.petersen@oracle.com, don.brace@microsemi.com, Sumit Saxena , ming.lei@redhat.com, bvanassche@acm.org, hare@suse.com, hch@lst.de, Shivasharan Srikanteshwara Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, esc.storagedev@microsemi.com, chenxiang66@hisilicon.com, "PDL,MEGARAIDLINUX" Content-Type: text/plain; charset="UTF-8" Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org > > > I also noticed nr_hw_queues are now exposed in sysfs - > > > > > > > /sys/devices/pci0000:85/0000:85:00.0/0000:86:00.0/0000:87:04.0/0000:8b > > > > > > :00.0/0000:8c:00.0/0000:8d:00.0/host14/scsi_host/host14/nr_hw_queues:1 > > > 28 > > > . > > > > That's on my v8 wip branch, so I guess you're picking it up from there. > > John - I did more testing on v8 wip branch. CPU hotplug is working as > expected, but I still see some performance issue on Logical Volumes. > > I created 8 Drives Raid-0 VD on MR controller and below is performance > impact of this RFC. Looks like contention is on single . > > I used command - "numactl -N 1 fio 1vd.fio --iodepth=128 --bs=4k -- > rw=randread --cpus_allowed_policy=split --ioscheduler=none -- > group_reporting --runtime=200 --numjobs=1" > IOPS without RFC = 300K IOPS with RFC = 230K. > > Perf top (shared host tag. IOPS = 230K) > > 13.98% [kernel] [k] sbitmap_any_bit_set > 6.43% [kernel] [k] blk_mq_run_hw_queue blk_mq_run_hw_queue function take more CPU which is called from " scsi_end_request" It looks like " blk_mq_hctx_has_pending" handles only elevator (scheduler) case. If queue has ioscheduler=none, we can skip. I case of scheduler=none, IO will be pushed to hardware queue and it by pass software queue. Based on above understanding, I added below patch and I can see performance scale back to expectation. Ming mentioned that - we cannot remove blk_mq_run_hw_queues() from IO completion path otherwise we may see IO hang. So I have just modified completion path assuming it is only required for IO scheduler case. https://www.spinics.net/lists/linux-block/msg55049.html Please review and let me know if this is good or we have to address with proper fix. diff --git a/block/blk-mq.c b/block/blk-mq.c index 1be7ac5a4040..b6a5b41b7fc2 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1559,6 +1559,9 @@ void blk_mq_run_hw_queues(struct request_queue *q, bool async) struct blk_mq_hw_ctx *hctx; int i; + if (!q->elevator) + return; + queue_for_each_hw_ctx(q, hctx, i) { if (blk_mq_hctx_stopped(hctx)) continue; Kashyap > 6.00% [kernel] [k] __audit_syscall_exit > 3.47% [kernel] [k] read_tsc > 3.19% [megaraid_sas] [k] complete_cmd_fusion > 3.19% [kernel] [k] irq_entries_start > 2.75% [kernel] [k] blk_mq_run_hw_queues > 2.45% fio [.] fio_gettime > 1.76% [kernel] [k] entry_SYSCALL_64 > 1.66% [kernel] [k] add_interrupt_randomness > 1.48% [megaraid_sas] [k] megasas_build_and_issue_cmd_fusion > 1.42% [kernel] [k] copy_user_generic_string > 1.36% [kernel] [k] scsi_queue_rq > 1.03% [kernel] [k] kmem_cache_alloc > 1.03% [kernel] [k] internal_get_user_pages_fast > 1.01% [kernel] [k] swapgs_restore_regs_and_return_to_usermode > 0.96% [kernel] [k] kmem_cache_free > 0.88% [kernel] [k] blkdev_direct_IO > 0.84% fio [.] td_io_queue > 0.83% [kernel] [k] __get_user_4 > > Perf top (shared host tag. IOPS = 300K) > > 6.36% [kernel] [k] unroll_tree_refs > 5.77% [kernel] [k] __do_softirq > 4.56% [kernel] [k] irq_entries_start > 4.38% [kernel] [k] read_tsc > 3.95% [megaraid_sas] [k] complete_cmd_fusion > 3.21% fio [.] fio_gettime > 2.98% [kernel] [k] add_interrupt_randomness > 1.79% [kernel] [k] entry_SYSCALL_64 > 1.61% [kernel] [k] copy_user_generic_string > 1.61% [megaraid_sas] [k] megasas_build_and_issue_cmd_fusion > 1.34% [kernel] [k] scsi_queue_rq > 1.11% [kernel] [k] kmem_cache_free > 1.05% [kernel] [k] blkdev_direct_IO > 1.05% [kernel] [k] internal_get_user_pages_fast > 1.00% [kernel] [k] __memset > 1.00% fio [.] td_io_queue > 0.98% [kernel] [k] kmem_cache_alloc > 0.94% [kernel] [k] __get_user_4 > 0.93% [kernel] [k] lookup_ioctx > 0.88% [kernel] [k] sbitmap_any_bit_set > > Kashyap > > > > > Thanks, > > John