From patchwork Tue Feb 2 03:10:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guoqing Jiang X-Patchwork-Id: 12060501 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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 B9D95C433E0 for ; Tue, 2 Feb 2021 03:11:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8352364E9A for ; Tue, 2 Feb 2021 03:11:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229819AbhBBDLK (ORCPT ); Mon, 1 Feb 2021 22:11:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229614AbhBBDLJ (ORCPT ); Mon, 1 Feb 2021 22:11:09 -0500 Received: from mail-il1-x12a.google.com (mail-il1-x12a.google.com [IPv6:2607:f8b0:4864:20::12a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C9ACC0613D6 for ; Mon, 1 Feb 2021 19:10:29 -0800 (PST) Received: by mail-il1-x12a.google.com with SMTP id q9so17747124ilo.1 for ; Mon, 01 Feb 2021 19:10:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloud.ionos.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=f1svkMvq9LBEb6D3mgoD1KYyrCbNxwAeUpEuA4/zYxA=; b=ShhF4A1rw8RCUiq3TleKhNJYz1JZa8AIEeI0BcUSa8ABNauMo8Pa0OYBJG3lruQ+Tk e5X+OrU7yLRZBc/jr5HHPQ0E+uIQb9IYnkpzGQlSQ3FuZzPXFmGSLDxKTXfhPkoJRhJJ gwYyyiO7oPi8gLZxOlTalH/AKNV12tnfu6hyQkOUEGGxvSZm658STGsdAknE4jbBpkff KOf0+N1/CliGQ55stFWrPYZdEpkpEuGgkVGzcABI9cN5gaI2fU9X63xU6MGAnQB2g70G +gU60nK4wwau/8remrJFJLPXjHHwkVKdXWwAihOnR2BgMHSNJx3ZuJ549rhpNSleUNjp NcNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=f1svkMvq9LBEb6D3mgoD1KYyrCbNxwAeUpEuA4/zYxA=; b=YJBQ19oYwr2lG34SS1iUq8TpDYJlzg02pSA441hhOQkYrP3F+KaXHAV8WYTEkxKiiz Yi+JCuhVCA6wHyBOY3++ZN/FT9eYcRdN3ZQPKOebRheeJv1FJLZyL+6EIMQ4fuSvi2I5 YHHQGGmTx0KtNHMAv7LePyNfq2wzRgECRF5I4cRdPUVXpRLnZ8ffOoW9PbKtoYl4vvJk RhyokA0Dgp9feY2HAUzmAbs7Px6xyGQ+kpgnZPIkZKXRizLbbZwtHOQT0kDbB2Mq/NL3 KhBnOqPza7+QUOv+SWlxmkZhSi/NOiWi3BA6p5fIdmPg7nk9d7FnPFtkL2rTHGkHf0Bd 3NmA== X-Gm-Message-State: AOAM532lW/LUQez8tbxtOkuGoeOI4EokcscsQhhdhcn2BdVwk3dosR6k DQUlEJ2KcgtQnogibQykID2LuQ== X-Google-Smtp-Source: ABdhPJw3EyuQSealbOoH4j+/dU6LapsBJDU5ylPO8as55bDQ5kIa0rASlrtKJGbOtJeb/z3z9OF8Tg== X-Received: by 2002:a05:6e02:1a25:: with SMTP id g5mr16116135ile.2.1612235428127; Mon, 01 Feb 2021 19:10:28 -0800 (PST) Received: from ls00508.pb.local ([2001:1438:4010:2540:c05c:3bba:187c:cddb]) by smtp.gmail.com with ESMTPSA id q5sm9099307ioi.43.2021.02.01.19.10.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Feb 2021 19:10:27 -0800 (PST) From: Guoqing Jiang To: axboe@kernel.dk Cc: linux-block@vger.kernel.org, danil.kipnis@cloud.ionos.com, jinpu.wang@cloud.ionos.com, Guoqing Jiang Subject: [PATCH V3 2/3] block: add a statistic table for io latency Date: Tue, 2 Feb 2021 04:10:08 +0100 Message-Id: <20210202031009.11584-3-guoqing.jiang@cloud.ionos.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210202031009.11584-1-guoqing.jiang@cloud.ionos.com> References: <20210202031009.11584-1-guoqing.jiang@cloud.ionos.com> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Usually, we get the status of block device by cat stat file, but we can only know the total time with that file. And we would like to know more accurate statistic, such as each latency range, which helps people to diagnose if there is issue about the hardware. This change is based on our internal patch from Florian-Ewald Mueller (florian-ewald.mueller@cloud.ionos.com). Reviewed-by: Jack Wang Signed-off-by: Guoqing Jiang --- Documentation/ABI/testing/sysfs-block | 8 ++++++ block/blk-core.c | 24 +++++++++++++++++ block/genhd.c | 37 +++++++++++++++++++++++++++ include/linux/part_stat.h | 5 ++++ 4 files changed, 74 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block index 503314efec13..c4db84c507dd 100644 --- a/Documentation/ABI/testing/sysfs-block +++ b/Documentation/ABI/testing/sysfs-block @@ -27,6 +27,14 @@ Description: For more details refer Documentation/admin-guide/iostats.rst +What: /sys/block//io_latency +Date: January 2021 +Contact: Guoqing Jiang +Description: + The /sys/block//io_latency files displays the I/O + latency of disk . With it, it is convenient to know + the statistics of I/O latency for each type (read, write, + discard and flush) which have happened to the disk. What: /sys/block///stat Date: February 2008 diff --git a/block/blk-core.c b/block/blk-core.c index 5e752840b41a..1adc9f17e8b7 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1264,6 +1264,26 @@ static void update_io_ticks(struct block_device *part, unsigned long now, } } +static void blk_additional_latency(struct block_device *part, const int sgrp, + struct request_queue *q, + unsigned long duration) +{ + unsigned int idx; + + if (!blk_queue_io_extra_stat(q)) + return; + + duration /= NSEC_PER_MSEC; + duration /= HZ_TO_MSEC_NUM; + if (likely(duration > 0)) { + idx = ilog2(duration); + if (idx > ADD_STAT_NUM - 1) + idx = ADD_STAT_NUM - 1; + } else + idx = 0; + part_stat_inc(part, latency_table[idx][sgrp]); +} + static void blk_account_io_completion(struct request *req, unsigned int bytes) { if (req->part && blk_do_io_stat(req)) { @@ -1288,6 +1308,8 @@ void blk_account_io_done(struct request *req, u64 now) part_stat_lock(); update_io_ticks(req->part, jiffies, true); + blk_additional_latency(req->part, sgrp, req->q, + now - req->start_time_ns); part_stat_inc(req->part, ios[sgrp]); part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns); part_stat_unlock(); @@ -1354,6 +1376,8 @@ static void __part_end_io_acct(struct block_device *part, unsigned int op, part_stat_lock(); update_io_ticks(part, now, true); + blk_additional_latency(part, sgrp, part->bd_disk->queue, + jiffies_to_nsecs(duration)); part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration)); part_stat_local_dec(part, in_flight[op_is_write(op)]); part_stat_unlock(); diff --git a/block/genhd.c b/block/genhd.c index 304f8dcc9a9b..09cb177421e0 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1146,6 +1146,42 @@ static struct device_attribute dev_attr_fail_timeout = __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store); #endif +static ssize_t io_latency_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct block_device *bdev = dev_to_bdev(dev); + size_t count = 0; + int i, sgrp; + + for (i = 0; i < ADD_STAT_NUM; i++) { + unsigned int from, to; + + if (i == ADD_STAT_NUM - 1) { + count += scnprintf(buf + count, PAGE_SIZE - count, " >= %5d ms: ", + (2 << (i - 2)) * HZ_TO_MSEC_NUM); + } else { + if (i < 2) { + from = i; + to = i + 1; + } else { + from = 2 << (i - 2); + to = 2 << (i - 1); + } + count += scnprintf(buf + count, PAGE_SIZE - count, "[%5d - %-5d) ms: ", + from * HZ_TO_MSEC_NUM, to * HZ_TO_MSEC_NUM); + } + + for (sgrp = 0; sgrp < NR_STAT_GROUPS; sgrp++) + count += scnprintf(buf + count, PAGE_SIZE - count, "%lu ", + part_stat_read(bdev, latency_table[i][sgrp])); + count += scnprintf(buf + count, PAGE_SIZE - count, "\n"); + } + + return count; +} + +static struct device_attribute dev_attr_io_latency = + __ATTR(io_latency, 0444, io_latency_show, NULL); + static struct attribute *disk_attrs[] = { &dev_attr_range.attr, &dev_attr_ext_range.attr, @@ -1165,6 +1201,7 @@ static struct attribute *disk_attrs[] = { #ifdef CONFIG_FAIL_IO_TIMEOUT &dev_attr_fail_timeout.attr, #endif + &dev_attr_io_latency.attr, NULL }; diff --git a/include/linux/part_stat.h b/include/linux/part_stat.h index d2558121d48c..e2bde5160de4 100644 --- a/include/linux/part_stat.h +++ b/include/linux/part_stat.h @@ -9,6 +9,11 @@ struct disk_stats { unsigned long sectors[NR_STAT_GROUPS]; unsigned long ios[NR_STAT_GROUPS]; unsigned long merges[NR_STAT_GROUPS]; + /* + * We measure latency (ms) for 1, 2, ..., 1024 and >=1024. + */ +#define ADD_STAT_NUM 12 + unsigned long latency_table[ADD_STAT_NUM][NR_STAT_GROUPS]; unsigned long io_ticks; local_t in_flight[2]; };