From patchwork Tue Sep 1 18:52:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tejun Heo X-Patchwork-Id: 11749371 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 C12CD166C for ; Tue, 1 Sep 2020 18:54:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A4B8820866 for ; Tue, 1 Sep 2020 18:54:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598986475; bh=InOQ+6F94LiBAqxNdhhEU3k85Aza8w0ZcOHPbzA+AC4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aK0a92i9e9+PKMq6zebaKM+kPhEo6bEO7K2M/1Ek4wf0F7gub8I6Z2oRuHMm7X3eg GySvOzhKw1r/qOff9GJQxLBvenMnKfhPgy5OCCE0sdVzxHqdLRpW6wEEMeZpuNrLZa /A6vpDpNCkXuws1zhJbPuBcLpdRJY8hBXDZZtT4s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731963AbgIASyd (ORCPT ); Tue, 1 Sep 2020 14:54:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731917AbgIASyW (ORCPT ); Tue, 1 Sep 2020 14:54:22 -0400 Received: from mail-qt1-x841.google.com (mail-qt1-x841.google.com [IPv6:2607:f8b0:4864:20::841]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E312C061245; Tue, 1 Sep 2020 11:54:21 -0700 (PDT) Received: by mail-qt1-x841.google.com with SMTP id 60so1735794qtc.9; Tue, 01 Sep 2020 11:54:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=m+qTmQYuX+yoSNUOz4jTM/Jvux+Eq7PX2lLyJ9lYHRM=; b=XipZHXfU9XrCtlGklpOQGNXRadhcHdExtLsTEZL7t60433LLNu7tEHGjQqBqMC+iR7 dzOZrvVvPn13/zRt1PKU3F9yOKmtRpSRDlUXyHHWyzh8LKcLYdSQ4C5U9dSjstz6fM0M j4gZRzS5tOd4+1i6w3lS3cx1sPdlhcRfer1SkYCs6qDq7Oi+WJoj+1xBKAZdM+qZd3XQ JnpfCe0cEXjxqluYe3gDlwQCygUtDoiivx5w4r914bM2z2dyq0ESorJJuIySt6s90gmS dVBA+q9jEx5wqCLzMbOcH/IX3zWUiR1PQnygRDH6WXwyH0wNqYOYCRbi0sFgurl8XLdC i9Rw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=m+qTmQYuX+yoSNUOz4jTM/Jvux+Eq7PX2lLyJ9lYHRM=; b=snSnaJkGV5z1+i3jtjIcUK5f2qsbX2MDEmhG2ZTAFWHCbXtF4LGse1SPfn10pAw/7u NUIfYJmKAZ5vi89amZPe32U0v9vLq9vuTVnnSKBmCJ7CqPj34bs8q8wsF2kHAd8x/yg7 NpT5QzX7z8FeqiBI2F3s+cmfssNHmxGQfRV7CJdxDqVykI5kMmvDVQkoYmVd3M014fyO kr6J5m8XXrTgqbJoz/wupnJnsC5UKKENi59Wk4e6jxpOgOT33lk0rArkHAYLWIHEDI/3 5pbONgDR2Vw07y5QpVwInbwQnwrml9QKspeaN9Z6Aq+h9fRw4gZW+6ypKudMH4YjNwo6 RNMg== X-Gm-Message-State: AOAM530We733ZwdkFYv/5m3KzdSj5qudSNgUyTOaq2/SYE9ts7U0LteP 5aDdrk3X8wjGNmkwg3/RQEs= X-Google-Smtp-Source: ABdhPJzUspyaN4Tu+/SqUVmwCZWio6vGZQ+22rInJpzfHUowHkMwaTKle0jWv9IsEhZA4s2chmePNw== X-Received: by 2002:ac8:6d32:: with SMTP id r18mr3346066qtu.246.1598986460695; Tue, 01 Sep 2020 11:54:20 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:a198]) by smtp.gmail.com with ESMTPSA id i65sm2409921qkf.126.2020.09.01.11.54.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Sep 2020 11:54:20 -0700 (PDT) From: Tejun Heo To: axboe@kernel.dk Cc: linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, newella@fb.com, Tejun Heo Subject: [PATCH 26/27] blk-iocost: add three debug stat - cost.wait, indebt and indelay Date: Tue, 1 Sep 2020 14:52:56 -0400 Message-Id: <20200901185257.645114-27-tj@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200901185257.645114-1-tj@kernel.org> References: <20200901185257.645114-1-tj@kernel.org> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org These are really cheap to collect and can be useful in debugging iocost behavior. Add them as debug stats for now. Signed-off-by: Tejun Heo --- block/blk-iocost.c | 77 +++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 72 insertions(+), 5 deletions(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 9366527d8c12..fc897bb142bc 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -452,6 +452,9 @@ struct iocg_pcpu_stat { struct iocg_stat { u64 usage_us; + u64 wait_us; + u64 indebt_us; + u64 indelay_us; }; /* per device-cgroup pair */ @@ -538,6 +541,9 @@ struct ioc_gq { struct iocg_stat last_stat; u64 last_stat_abs_vusage; u64 usage_delta_us; + u64 wait_since; + u64 indebt_since; + u64 indelay_since; /* this iocg's depth in the hierarchy and ancestors including self */ int level; @@ -1303,9 +1309,15 @@ static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now) } if (delay >= MIN_DELAY) { + if (!iocg->indelay_since) + iocg->indelay_since = now->now; blkcg_set_delay(blkg, delay * NSEC_PER_USEC); return true; } else { + if (iocg->indelay_since) { + iocg->local_stat.indelay_us += now->now - iocg->indelay_since; + iocg->indelay_since = 0; + } iocg->delay = 0; blkcg_clear_delay(blkg); return false; @@ -1325,8 +1337,10 @@ static void iocg_incur_debt(struct ioc_gq *iocg, u64 abs_cost, * Once in debt, debt handling owns inuse. @iocg stays at the minimum * inuse donating all of it share to others until its debt is paid off. */ - if (!iocg->abs_vdebt && abs_cost) + if (!iocg->abs_vdebt && abs_cost) { + iocg->indebt_since = now->now; propagate_weights(iocg, iocg->active, 0, false, now); + } iocg->abs_vdebt += abs_cost; @@ -1348,9 +1362,13 @@ static void iocg_pay_debt(struct ioc_gq *iocg, u64 abs_vpay, iocg->abs_vdebt -= min(abs_vpay, iocg->abs_vdebt); /* if debt is paid in full, restore inuse */ - if (!iocg->abs_vdebt) + if (!iocg->abs_vdebt) { + iocg->local_stat.indebt_us += now->now - iocg->indebt_since; + iocg->indebt_since = 0; + propagate_weights(iocg, iocg->active, iocg->last_inuse, false, now); + } } static int iocg_wake_fn(struct wait_queue_entry *wq_entry, unsigned mode, @@ -1436,8 +1454,17 @@ static void iocg_kick_waitq(struct ioc_gq *iocg, bool pay_debt, __wake_up_locked_key(&iocg->waitq, TASK_NORMAL, &ctx); - if (!waitqueue_active(&iocg->waitq)) + if (!waitqueue_active(&iocg->waitq)) { + if (iocg->wait_since) { + iocg->local_stat.wait_us += now->now - iocg->wait_since; + iocg->wait_since = 0; + } return; + } + + if (!iocg->wait_since) + iocg->wait_since = now->now; + if (WARN_ON_ONCE(ctx.vbudget >= 0)) return; @@ -1579,8 +1606,15 @@ static void iocg_flush_stat_one(struct ioc_gq *iocg, struct ioc_now *now) iocg->usage_delta_us = div64_u64(vusage_delta, ioc->vtime_base_rate); iocg->local_stat.usage_us += iocg->usage_delta_us; + /* propagate upwards */ new_stat.usage_us = iocg->local_stat.usage_us + iocg->desc_stat.usage_us; + new_stat.wait_us = + iocg->local_stat.wait_us + iocg->desc_stat.wait_us; + new_stat.indebt_us = + iocg->local_stat.indebt_us + iocg->desc_stat.indebt_us; + new_stat.indelay_us = + iocg->local_stat.indelay_us + iocg->desc_stat.indelay_us; /* propagate the deltas to the parent */ if (iocg->level > 0) { @@ -1589,6 +1623,12 @@ static void iocg_flush_stat_one(struct ioc_gq *iocg, struct ioc_now *now) parent_stat->usage_us += new_stat.usage_us - iocg->last_stat.usage_us; + parent_stat->wait_us += + new_stat.wait_us - iocg->last_stat.wait_us; + parent_stat->indebt_us += + new_stat.indebt_us - iocg->last_stat.indebt_us; + parent_stat->indelay_us += + new_stat.indelay_us - iocg->last_stat.indelay_us; } iocg->last_stat = new_stat; @@ -1961,8 +2001,6 @@ static void ioc_timer_fn(struct timer_list *timer) return; } - iocg_flush_stat(&ioc->active_iocgs, &now); - /* * Waiters determine the sleep durations based on the vrate they * saw at the time of sleep. If vrate has increased, some waiters @@ -1976,6 +2014,22 @@ static void ioc_timer_fn(struct timer_list *timer) spin_lock(&iocg->waitq.lock); + /* flush wait and indebt stat deltas */ + if (iocg->wait_since) { + iocg->local_stat.wait_us += now.now - iocg->wait_since; + iocg->wait_since = now.now; + } + if (iocg->indebt_since) { + iocg->local_stat.indebt_us += + now.now - iocg->indebt_since; + iocg->indebt_since = now.now; + } + if (iocg->indelay_since) { + iocg->local_stat.indelay_us += + now.now - iocg->indelay_since; + iocg->indelay_since = now.now; + } + if (waitqueue_active(&iocg->waitq) || iocg->abs_vdebt || iocg->delay) { /* might be oversleeping vtime / hweight changes, kick */ @@ -2010,6 +2064,12 @@ static void ioc_timer_fn(struct timer_list *timer) } commit_weights(ioc); + /* + * Wait and indebt stat are flushed above and the donation calculation + * below needs updated usage stat. Let's bring stat up-to-date. + */ + iocg_flush_stat(&ioc->active_iocgs, &now); + /* calc usage and see whether some weights need to be moved around */ list_for_each_entry(iocg, &ioc->active_iocgs, active_list) { u64 vdone, vtime, usage_us, usage_dur; @@ -2835,6 +2895,13 @@ static size_t ioc_pd_stat(struct blkg_policy_data *pd, char *buf, size_t size) pos += scnprintf(buf + pos, size - pos, " cost.usage=%llu", iocg->last_stat.usage_us); + if (blkcg_debug_stats) + pos += scnprintf(buf + pos, size - pos, + " cost.wait=%llu cost.indebt=%llu cost.indelay=%llu", + iocg->last_stat.wait_us, + iocg->last_stat.indebt_us, + iocg->last_stat.indelay_us); + return pos; }