From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.174 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793198185; b=Ukti4EZlrRQKm0uN+ldUDmNubDI0uCqAXqgJB1sbcnLfTSEsULnep/Pz3Ltihh4w1dTr aXEnQQJ3Jdax772XijBTNemWeSx954VHP5eBSdX5GikRE/HZJswzTkOnDtcIIG7FQLEaX pJsXlTAFsnQXS/rxlSkEkkOCZt+3ULb1fnwOg76F15D6kcM7Y0uw7I8It20mryGLy18mw Kazc2DWubbL2XpN9Afmt58j8cgfHEMsXTvkUMGGrcLC+piPoXahLoUV4hjuNOoN+x8DjA 1q13yc6Dmr/Y+mtwllS5LMhXFa4ge04+T+RNkycAln3rLVDEAexlqqfPUGwbOXr8z9w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793198185; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=Fb6/26WA939AMYDIj8vbwu42PlzOHlRCw3Lo25skONU=; b=x9m7+ZDr61fwtav80g0RtxP41SIr1+PV9Lu21/+o8PZGFefvhEUQOytm891bp0q2wPdK vW6UJPOIVrYd6SsoVLyAo8oyywgZpdoniFyU73TDGO0rWztSsxceaTqDo6lhwWBaC1ooi 7ur4ejXLsHwHIbycd+Z03RsvEqHz/VCX3nOsYCDYCivC+tvGB+wKSUgmDgs/qRYETW4EP v1yTpA44vhHhUcJPafAPEWoNOXcs5Z1QJhh5XV56mZLorOC+FWpGdVm3JN/aKgeu/uXfp uKjU+31IugkOWf84E8BVjNmGyPb5I2x4liObKyf/ravhP5SwCKrHE+LnghE9Ts85sgg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=W5iUN83u; arc=none smtp.remote-ip=91.218.175.174 Received: from mta0.migadu.com (out-174.mta0.migadu.com [91.218.175.174]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0511F60A2615 for ; Wed, 28 Oct 2026 14:36:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 0511F60A2615 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=W5iUN83u X-Envelope-To: bpf@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=69I1hqUqyZ5FLhAiygZ4lbg2me7OFFPxt1wO9/rvtLk=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793198183; v=1; x=1793802983; b=W5iUN83uBYeykhY7n8JRMNUzPH7ANNOvMN19oSMo6IasGjaDblMulxH/bYkQVh0Fu5ihQknM mF8Va8wpAqtPTVpQN+NCN6aqmSfxUEPqvbhF8E+U6MRoDznI/1yu6I1jaUezGTMGd61IcEzMcdb bqd7uS0qYW5UkCNeSPa2/WlQ= X-Envelope-To: bpf@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 4bde4a18922df54b; Wed, 28 Oct 2026 14:36:23 +0000 X-Mizu-Trace-ID: 4bde4a18922df54b X-Migadu-Flow: FLOW_OUT From: Tao Cui To: tj@kernel.org, josef@toxicopanda.com, axboe@kernel.dk Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, andrii@kernel.org, eddyz87@gmail.com, ast@kernel.org, daniel@iogearbox.net, linux-kselftest@vger.kernel.org, cui.tao@linux.dev, cuitao@kylinos.cn, ameryhung@gmail.com, alexei.starovoitov@gmail.com Subject: [PATCH 4/5] blk-iocost: add iocost_ioc_tick tracepoint for per-period device summary Date: Wed, 28 Oct 2026 22:35:33 +0800 Message-ID: <20261028143534.135968-5-cui.tao@linux.dev> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261028143534.135968-1-cui.tao@linux.dev> References: <20261028143534.135968-1-cui.tao@linux.dev> X-Mailing-List: bpf@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tao Cui Add iocost_ioc_tick, emitted once per period from ioc_timer_fn() with the overall controller state: period_us, vrate, busy_level, active iocg count and usage percentage. It reads the values the period ran in: the event is emitted before the vrate adjustment and the period transition, so each tick reports the completed period. It fires every period the controller is running, including steady states, plus one final tick before the controller goes idle, which reads active=0, making the transition to dormancy (e.g. a device saturated entirely by uncharged IO) directly visible. Suggested-by: Tejun Heo Signed-off-by: Tao Cui --- MAINTAINERS | 1 + block/blk-iocost.c | 13 +++++++++++ include/trace/events/iocost.h | 43 +++++++++++++++++++++++++++++++++++ 3 files changed, 57 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index 598a5f65423d..a6a39279d266 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6832,6 +6832,7 @@ F: block/blk-iocost.h F: block/blk-iolatency.c F: block/blk-throttle.c F: include/linux/blk-cgroup.h +F: include/trace/events/iocost.h CONTROL GROUP - CPUSET M: Waiman Long diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 1e84232e6740..9f7f5e5f0ebb 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -1839,6 +1839,7 @@ static void ioc_timer_fn(struct timer_list *timer) struct ioc_now now; LIST_HEAD(surpluses); int nr_debtors, nr_shortages = 0, nr_lagging = 0; + int nr_active = 0; u64 usage_us_sum = 0; u32 ppm_rthr; u32 ppm_wthr; @@ -1875,6 +1876,8 @@ static void ioc_timer_fn(struct timer_list *timer) u64 vdone, vtime, usage_us; u32 hw_active, hw_inuse; + nr_active++; + /* * Collect unused and wind vtime closer to vnow to prevent * iocgs from accumulating a large amount of budget. @@ -2036,6 +2039,16 @@ static void ioc_timer_fn(struct timer_list *timer) ioc->busy_level = clamp(ioc->busy_level, -1000, 1000); + /* + * Everything the tick reports is final here: busy_level was just + * computed, cur_period hasn't changed, nr_active and usage_us_sum are + * complete, and vrate and period_us still hold the values this period + * ran in. usage is wall time over wall time, summed over iocgs, and is + * not capped at 100. Emit before the refresh below so the event reads + * the completed period directly. + */ + trace_iocost_ioc_tick(ioc, &now, nr_active, usage_us_sum); + ioc_adjust_base_vrate(ioc, rq_wait_pct, nr_lagging, nr_shortages, prev_busy_level, missed_ppm); diff --git a/include/trace/events/iocost.h b/include/trace/events/iocost.h index e772b1bc60d6..39229605f499 100644 --- a/include/trace/events/iocost.h +++ b/include/trace/events/iocost.h @@ -178,6 +178,49 @@ TRACE_EVENT(iocost_ioc_vrate_adj, ) ); +/* + * Periodic per-device summary, emitted once per period before the vrate + * adjustment and the period transition in ioc_timer_fn(). Unlike the + * state-change events above, this fires every period the controller is + * running, including steady states, and carries the overall controller state + * so basic monitoring doesn't require drgn. + */ +TRACE_EVENT(iocost_ioc_tick, + + TP_PROTO(struct ioc *ioc, const struct ioc_now *now, + int nr_active, u64 usage_us_sum), + + TP_ARGS(ioc, now, nr_active, usage_us_sum), + + TP_STRUCT__entry ( + __string(devname, ioc_name(ioc)) + __field(u64, cur_period) + __field(u32, period_us) + __field(u64, vrate) + __field(int, busy_level) + __field(int, nr_active) + __field(u32, usage_pct) + ), + + TP_fast_assign( + __assign_str(devname); + __entry->cur_period = atomic64_read(&ioc->cur_period); + __entry->period_us = ioc->period_us; + __entry->vrate = ioc->vtime_base_rate; + __entry->busy_level = ioc->busy_level; + __entry->nr_active = nr_active; + __entry->usage_pct = now->now > ioc->period_at ? + div64_u64(usage_us_sum * 100, + now->now - ioc->period_at) : 0; + ), + + TP_printk("[%s] period=%llu:%uus vrate=%llu busy=%d active=%d usage=%u%%", + __get_str(devname), __entry->cur_period, __entry->period_us, + __entry->vrate, __entry->busy_level, __entry->nr_active, + __entry->usage_pct + ) +); + TRACE_EVENT(iocost_iocg_forgive_debt, TP_PROTO(struct ioc_gq *iocg, const char *path, struct ioc_now *now, -- 2.43.0