From patchwork Mon Jul 13 21:13:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guoqing Jiang X-Patchwork-Id: 11661021 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 77EF0618 for ; Mon, 13 Jul 2020 21:13:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 593162082E for ; Mon, 13 Jul 2020 21:13:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cloud.ionos.com header.i=@cloud.ionos.com header.b="KqHuHUAn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726446AbgGMVNz (ORCPT ); Mon, 13 Jul 2020 17:13:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726400AbgGMVNz (ORCPT ); Mon, 13 Jul 2020 17:13:55 -0400 Received: from mail-ej1-x642.google.com (mail-ej1-x642.google.com [IPv6:2a00:1450:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3872CC061755 for ; Mon, 13 Jul 2020 14:13:55 -0700 (PDT) Received: by mail-ej1-x642.google.com with SMTP id dp18so19019433ejc.8 for ; Mon, 13 Jul 2020 14:13:55 -0700 (PDT) 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=nvoC+buu5tasYx6T8UBAK6LFJaCdJgALnFZc/9QT04M=; b=KqHuHUAnCR/6DqOS8U6H/f4y0mOneoVWxjNEMglmjVVvv85PlkzQpvQpgroFZXq0fO VmcvAZhanPBHQIcMFmxQ2Dhc/ODSYB8f6SPRqwdvCM7uQ2dzsjm+DZZwK+hX7MW+ynKA +SR3UBOH9tYA5GYDXl+jTn/oOeTMGa/YjjydtcmT3vmWPWsZ3ipVnnSFnGNBhXHvBGyf tR0i7mRp8W+h3t6j8dCmuz0l30ZKldDV11JTB4MBlJ/yIGGO38c+aGfNkZIDmjjigTh0 cjbQMHHzijLU5jDisAmDVC8sxZB+KcRgFmXnsmCOdhmV08O0H/aQreF1JUFCOWvEvCgH ko6Q== 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=nvoC+buu5tasYx6T8UBAK6LFJaCdJgALnFZc/9QT04M=; b=XBCcIUZ/MHr1/9KoULuboH1nnbdR56zOWJWnViDXGdYFaEt0GzrMSGJh/8guH+2aws eua/cJnPZ2YmAZISMD3WSspjwakDrvlm2IVHBEkmdPG/0myUT5gf5dsO1rOxPXHn/5Z4 O0V72OHBHN3y71AM8zuUZ0p0au2ekjrnZZFAzyG4oGd0WOCGIRKDiBfBVzdnG037hQgY h0NNQmbRnEJ0aNT3eoZBQGHuHjfaaCot8GHrG+Nm9IiWVSx0elr7JSGQpEatQEIGwT9b 3LgL5/Vo+yuFEQoRHpIkYQsaS/Gf6jgZj1e+xOx9YjRKcNnbCuhYy/xQbStjtGAUsu/Y XzIQ== X-Gm-Message-State: AOAM533m/yP2pe9o3k7oOLAGZA+OoT/uZiva4tm+e6ZnLwDLRR/sDf/r WCBcvAX6Lxyh4GWTkbJpS8APLQ== X-Google-Smtp-Source: ABdhPJxxM+lXnY1Pv5jC54SILewDa0FsTTF0olUY17HzRDOMvh8J3mDj/T/HYIIXLvmQ1k48kM7r6w== X-Received: by 2002:a17:906:7c07:: with SMTP id t7mr1626502ejo.487.1594674833855; Mon, 13 Jul 2020 14:13:53 -0700 (PDT) Received: from ls00508.pb.local ([2001:1438:4010:2540:a1ab:24b8:5892:2244]) by smtp.gmail.com with ESMTPSA id d5sm12715770eds.40.2020.07.13.14.13.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Jul 2020 14:13:53 -0700 (PDT) From: Guoqing Jiang To: axboe@kernel.dk Cc: linux-block@vger.kernel.org, Guoqing Jiang , Florian-Ewald Mueller Subject: [PATCH RFC V2 1/4] block: add a statistic table for io latency Date: Mon, 13 Jul 2020 23:13:18 +0200 Message-Id: <20200713211321.21123-2-guoqing.jiang@cloud.ionos.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200713211321.21123-1-guoqing.jiang@cloud.ionos.com> References: <20200713211321.21123-1-guoqing.jiang@cloud.ionos.com> Sender: linux-block-owner@vger.kernel.org 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. Also a new config option is introduced to control if people want to know the additional statistics or not, and we use the option for io sector in next patch. Signed-off-by: Florian-Ewald Mueller Signed-off-by: Guoqing Jiang --- block/Kconfig | 8 ++++++++ block/blk-core.c | 34 ++++++++++++++++++++++++++++++++++ block/genhd.c | 26 ++++++++++++++++++++++++++ include/linux/part_stat.h | 7 +++++++ 4 files changed, 75 insertions(+) diff --git a/block/Kconfig b/block/Kconfig index bbad5e8bbffe..360f63111e2d 100644 --- a/block/Kconfig +++ b/block/Kconfig @@ -176,6 +176,14 @@ config BLK_DEBUG_FS Unless you are building a kernel for a tiny system, you should say Y here. +config BLK_ADDITIONAL_DISKSTAT + bool "Block layer additional diskstat" + default n + help + Enabling this option adds io latency statistics for each block device. + + If unsure, say N. + config BLK_DEBUG_FS_ZONED bool default BLK_DEBUG_FS && BLK_DEV_ZONED diff --git a/block/blk-core.c b/block/blk-core.c index d9d632639bd1..036eb04782de 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1411,6 +1411,34 @@ static void update_io_ticks(struct hd_struct *part, unsigned long now, bool end) } } +#ifdef CONFIG_BLK_ADDITIONAL_DISKSTAT +/* + * Either account additional stat for request if req is not NULL or account for bio. + */ +static void blk_additional_latency(struct hd_struct *part, const int sgrp, + struct request *req, unsigned long start_jiffies) +{ + unsigned int idx; + unsigned long duration, now = READ_ONCE(jiffies); + + if (req) + duration = jiffies_to_nsecs(now) - req->start_time_ns; + else + duration = jiffies_to_nsecs(now - start_jiffies); + + 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]); + +} +#endif + static void blk_account_io_completion(struct request *req, unsigned int bytes) { if (req->part && blk_do_io_stat(req)) { @@ -1440,6 +1468,9 @@ void blk_account_io_done(struct request *req, u64 now) part = req->part; update_io_ticks(part, jiffies, true); +#ifdef CONFIG_BLK_ADDITIONAL_DISKSTAT + blk_additional_latency(part, sgrp, req, 0); +#endif part_stat_inc(part, ios[sgrp]); part_stat_add(part, nsecs[sgrp], now - req->start_time_ns); part_stat_unlock(); @@ -1488,6 +1519,9 @@ void disk_end_io_acct(struct gendisk *disk, unsigned int op, part_stat_lock(); update_io_ticks(part, now, true); +#ifdef CONFIG_BLK_ADDITIONAL_DISKSTAT + blk_additional_latency(part, sgrp, NULL, start_time); +#endif 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 c42a49f2f537..f5d2f110fb34 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1420,6 +1420,29 @@ static struct device_attribute dev_attr_fail_timeout = __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store); #endif +#ifdef CONFIG_BLK_ADDITIONAL_DISKSTAT +static ssize_t io_latency_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct hd_struct *p = dev_to_part(dev); + size_t count = 0; + int i, sgrp; + + for (i = 0; i < ADD_STAT_NUM; i++) { + count += scnprintf(buf + count, PAGE_SIZE - count, "%5d ms: ", + (1 << i) * HZ_TO_MSEC_NUM); + for (sgrp = 0; sgrp < NR_STAT_GROUPS; sgrp++) + count += scnprintf(buf + count, PAGE_SIZE - count, "%lu ", + part_stat_read(p, 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); +#endif + static struct attribute *disk_attrs[] = { &dev_attr_range.attr, &dev_attr_ext_range.attr, @@ -1438,6 +1461,9 @@ static struct attribute *disk_attrs[] = { #endif #ifdef CONFIG_FAIL_IO_TIMEOUT &dev_attr_fail_timeout.attr, +#endif +#ifdef CONFIG_BLK_ADDITIONAL_DISKSTAT + &dev_attr_io_latency.attr, #endif NULL }; diff --git a/include/linux/part_stat.h b/include/linux/part_stat.h index 24125778ef3e..fe3def8c69d7 100644 --- a/include/linux/part_stat.h +++ b/include/linux/part_stat.h @@ -9,6 +9,13 @@ struct disk_stats { unsigned long sectors[NR_STAT_GROUPS]; unsigned long ios[NR_STAT_GROUPS]; unsigned long merges[NR_STAT_GROUPS]; +#ifdef CONFIG_BLK_ADDITIONAL_DISKSTAT +/* + * 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]; +#endif unsigned long io_ticks; local_t in_flight[2]; };