From patchwork Fri Jul 28 09:58:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 708382 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79707C0015E for ; Fri, 28 Jul 2023 10:02:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235511AbjG1KCx (ORCPT ); Fri, 28 Jul 2023 06:02:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235380AbjG1KC3 (ORCPT ); Fri, 28 Jul 2023 06:02:29 -0400 Received: from cloudserver094114.home.pl (cloudserver094114.home.pl [79.96.170.134]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5F91423B; Fri, 28 Jul 2023 03:01:59 -0700 (PDT) Received: from localhost (127.0.0.1) (HELO v370.home.net.pl) by /usr/run/smtp (/usr/run/postfix/private/idea_relay_lmtp) via UNIX with SMTP (IdeaSmtpServer 5.2.0) id 5ad84d9e2afdf0c6; Fri, 28 Jul 2023 12:01:58 +0200 Authentication-Results: v370.home.net.pl; spf=softfail (domain owner discourages use of this host) smtp.mailfrom=rjwysocki.net (client-ip=195.136.19.94; helo=[195.136.19.94]; envelope-from=rjw@rjwysocki.net; receiver=) Received: from kreacher.localnet (unknown [195.136.19.94]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by v370.home.net.pl (Postfix) with ESMTPSA id C2326661E37; Fri, 28 Jul 2023 12:01:57 +0200 (CEST) From: "Rafael J. Wysocki" To: Linux PM Cc: LKML , Peter Zijlstra , Anna-Maria Behnsen , Frederic Weisbecker , Kajetan Puchalski Subject: [PATCH v2 1/3] cpuidle: teo: Update idle duration estimate when choosing shallower state Date: Fri, 28 Jul 2023 11:58:45 +0200 Message-ID: <13326870.uLZWGnKmhe@kreacher> In-Reply-To: <5707588.DvuYhMxLoT@kreacher> References: <5707588.DvuYhMxLoT@kreacher> MIME-Version: 1.0 X-CLIENT-IP: 195.136.19.94 X-CLIENT-HOSTNAME: 195.136.19.94 X-VADE-SPAMSTATE: clean X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedviedrieeigddvtdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfjqffogffrnfdpggftiffpkfenuceurghilhhouhhtmecuudehtdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvvefufffkjghfggfgtgesthfuredttddtjeenucfhrhhomhepfdftrghfrggvlhculfdrucghhihsohgtkhhifdcuoehrjhifsehrjhifhihsohgtkhhirdhnvghtqeenucggtffrrghtthgvrhhnpedvffeuiedtgfdvtddugeeujedtffetteegfeekffdvfedttddtuefhgeefvdejhfenucfkphepudelhedrudefiedrudelrdelgeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpeduleehrddufeeirdduledrleegpdhhvghlohepkhhrvggrtghhvghrrdhlohgtrghlnhgvthdpmhgrihhlfhhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqpdhnsggprhgtphhtthhopeeipdhrtghpthhtoheplhhinhhugidqphhmsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepphgvthgvrhiisehinhhfrhgruggvrggurdhorhhgpdhrtghpthhtoheprghnnhgrqdhmrghrihgrsehlihhnuhhtrhhonhhigidruggvpdhrtghpthhtohepfhhrvggu vghrihgtsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehkrghjvghtrghnrdhpuhgthhgrlhhskhhisegrrhhmrdgtohhm X-DCC--Metrics: v370.home.net.pl 1024; Body=6 Fuz1=6 Fuz2=6 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Rafael J. Wysocki The TEO governor takes CPU utilization into account by refining idle state selection when the utilization is above a certain threshold. This is done by choosing an idle state shallower than the previously selected one. However, when doing this, the idle duration estimate needs to be adjusted so as to prevent the scheduler tick from being stopped when the candidate idle state is shallow, which may lead to excessive energy usage if the CPU is not woken up quickly enough going forward. Moreover, if the scheduler tick has been stopped already and the new idle duration estimate is too small, the replacement candidate state cannot be used. Modify the relevant code to take the above observations into account. Fixes: 9ce0f7c4bc64 ("cpuidle: teo: Introduce util-awareness") Signed-off-by: Rafael J. Wysocki --- v1 -> v2: * Rework the code handling the special case when the CPU is utilized and there are only 2 idle states (drop the loop, avoid using state 0 when the tick has been stopped already and it is too shallow, check if state 1 is not disabled when about to use it, set low idle duration estimate). * Changelog edits. --- drivers/cpuidle/governors/teo.c | 43 ++++++++++++++++++++++++++++++---------- 1 file changed, 33 insertions(+), 10 deletions(-) Index: linux-pm/drivers/cpuidle/governors/teo.c =================================================================== --- linux-pm.orig/drivers/cpuidle/governors/teo.c +++ linux-pm/drivers/cpuidle/governors/teo.c @@ -397,13 +397,26 @@ static int teo_select(struct cpuidle_dri * the shallowest non-polling state and exit. */ if (drv->state_count < 3 && cpu_data->utilized) { - for (i = 0; i < drv->state_count; ++i) { - if (!dev->states_usage[i].disable && - !(drv->states[i].flags & CPUIDLE_FLAG_POLLING)) { - idx = i; - goto end; - } - } + /* The CPU is utilized, so assume a short idle duration. */ + duration_ns = teo_middle_of_bin(0, drv); + /* + * If state 0 is enabled and it is not a polling one, select it + * right away unless the scheduler tick has been stopped, in + * which case care needs to be taken to leave the CPU in a + * deep enough state in case it is not woken up any time soon + * after all. + */ + if (!idx && !(drv->states[0].flags & CPUIDLE_FLAG_POLLING) && + teo_time_ok(duration_ns)) + goto end; + + /* + * Assume that state 1 is not a polling one and select it + * unless it is disabled, in which case state 0 must be used + * no matter what. + */ + idx = dev->states_usage[1].disable ? 0 : 1; + goto end; } /* @@ -539,10 +552,20 @@ static int teo_select(struct cpuidle_dri /* * If the CPU is being utilized over the threshold, choose a shallower - * non-polling state to improve latency + * non-polling state to improve latency, unless the scheduler tick has + * been stopped already and the shallower state's target residency is + * not sufficiently large. */ - if (cpu_data->utilized) - idx = teo_find_shallower_state(drv, dev, idx, duration_ns, true); + if (cpu_data->utilized) { + s64 span_ns; + + i = teo_find_shallower_state(drv, dev, idx, duration_ns, true); + span_ns = teo_middle_of_bin(i, drv); + if (teo_time_ok(span_ns)) { + idx = i; + duration_ns = span_ns; + } + } end: /* From patchwork Fri Jul 28 10:00:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 707874 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28B19C001DE for ; Fri, 28 Jul 2023 10:02:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235252AbjG1KCv (ORCPT ); Fri, 28 Jul 2023 06:02:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37192 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235349AbjG1KC3 (ORCPT ); Fri, 28 Jul 2023 06:02:29 -0400 Received: from cloudserver094114.home.pl (cloudserver094114.home.pl [79.96.170.134]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2AE0149CA; Fri, 28 Jul 2023 03:01:59 -0700 (PDT) Received: from localhost (127.0.0.1) (HELO v370.home.net.pl) by /usr/run/smtp (/usr/run/postfix/private/idea_relay_lmtp) via UNIX with SMTP (IdeaSmtpServer 5.2.0) id da2d6a680178221d; Fri, 28 Jul 2023 12:01:57 +0200 Authentication-Results: v370.home.net.pl; spf=softfail (domain owner discourages use of this host) smtp.mailfrom=rjwysocki.net (client-ip=195.136.19.94; helo=[195.136.19.94]; envelope-from=rjw@rjwysocki.net; receiver=) Received: from kreacher.localnet (unknown [195.136.19.94]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by v370.home.net.pl (Postfix) with ESMTPSA id 0B801661E3D; Fri, 28 Jul 2023 12:01:57 +0200 (CEST) From: "Rafael J. Wysocki" To: Linux PM Cc: LKML , Peter Zijlstra , Anna-Maria Behnsen , Frederic Weisbecker , Kajetan Puchalski Subject: [PATCH v2 2/3] cpuidle: teo: Avoid stopping the tick unnecessarily when bailing out Date: Fri, 28 Jul 2023 12:00:46 +0200 Message-ID: <3254124.aeNJFYEL58@kreacher> In-Reply-To: <5707588.DvuYhMxLoT@kreacher> References: <5707588.DvuYhMxLoT@kreacher> MIME-Version: 1.0 X-CLIENT-IP: 195.136.19.94 X-CLIENT-HOSTNAME: 195.136.19.94 X-VADE-SPAMSTATE: clean X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedviedrieeigddvtdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfjqffogffrnfdpggftiffpkfenuceurghilhhouhhtmecuudehtdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvvefufffkjghfggfgtgesthfuredttddtjeenucfhrhhomhepfdftrghfrggvlhculfdrucghhihsohgtkhhifdcuoehrjhifsehrjhifhihsohgtkhhirdhnvghtqeenucggtffrrghtthgvrhhnpedvffeuiedtgfdvtddugeeujedtffetteegfeekffdvfedttddtuefhgeefvdejhfenucfkphepudelhedrudefiedrudelrdelgeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpeduleehrddufeeirdduledrleegpdhhvghlohepkhhrvggrtghhvghrrdhlohgtrghlnhgvthdpmhgrihhlfhhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqpdhnsggprhgtphhtthhopeeipdhrtghpthhtoheplhhinhhugidqphhmsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepphgvthgvrhiisehinhhfrhgruggvrggurdhorhhgpdhrtghpthhtoheprghnnhgrqdhmrghrihgrsehlihhnuhhtrhhonhhigidruggvpdhrtghpthhtohepfhhrvggu vghrihgtsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehkrghjvghtrghnrdhpuhgthhgrlhhskhhisegrrhhmrdgtohhm X-DCC--Metrics: v370.home.net.pl 1024; Body=6 Fuz1=6 Fuz2=6 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Rafael J. Wysocki When teo_select() is going to return early in some special cases, make it avoid stopping the tick if the idle state to be returned is shallow. Signed-off-by: Rafael J. Wysocki --- drivers/cpuidle/governors/teo.c | 50 +++++++++++++++++++++++++--------------- 1 file changed, 32 insertions(+), 18 deletions(-) Index: linux-pm/drivers/cpuidle/governors/teo.c =================================================================== --- linux-pm.orig/drivers/cpuidle/governors/teo.c +++ linux-pm/drivers/cpuidle/governors/teo.c @@ -462,9 +462,9 @@ static int teo_select(struct cpuidle_dri /* Avoid unnecessary overhead. */ if (idx < 0) { idx = 0; /* No states enabled, must use 0. */ - goto end; + goto bail_out; } else if (idx == idx0) { - goto end; + goto bail_out; } /* @@ -547,8 +547,10 @@ static int teo_select(struct cpuidle_dri * If there is a latency constraint, it may be necessary to select an * idle state shallower than the current candidate one. */ - if (idx > constraint_idx) + if (idx > constraint_idx) { idx = constraint_idx; + goto bail_out; + } /* * If the CPU is being utilized over the threshold, choose a shallower @@ -569,23 +571,35 @@ static int teo_select(struct cpuidle_dri end: /* - * Don't stop the tick if the selected state is a polling one or if the - * expected idle duration is shorter than the tick period length. + * Allow the tick to be stopped unless the selected state is a polling + * one or the expected idle duration is shorter than the tick period + * length. */ - if (((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) || - duration_ns < TICK_NSEC) && !tick_nohz_tick_stopped()) { - *stop_tick = false; + if ((!(drv->states[idx].flags & CPUIDLE_FLAG_POLLING) && + duration_ns >= TICK_NSEC) || tick_nohz_tick_stopped()) + return idx; - /* - * The tick is not going to be stopped, so if the target - * residency of the state to be returned is not within the time - * till the closest timer including the tick, try to correct - * that. - */ - if (idx > idx0 && - drv->states[idx].target_residency_ns > delta_tick) - idx = teo_find_shallower_state(drv, dev, idx, delta_tick, false); - } +retain_tick: + *stop_tick = false; + + /* + * The tick is not going to be stopped, so if the target residency of + * the state to be returned is not within the time till the closest + * timer including the tick, try to correct that. + */ + if (idx > idx0 && + drv->states[idx].target_residency_ns > delta_tick) + idx = teo_find_shallower_state(drv, dev, idx, delta_tick, false); + + return idx; + +bail_out: + /* + * Do not allow the tick to be stopped if the selected state is shallow + * enough. + */ + if (drv->states[idx].target_residency_ns < TICK_NSEC) + goto retain_tick; return idx; } From patchwork Fri Jul 28 10:01:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 708383 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E69FAC41513 for ; Fri, 28 Jul 2023 10:02:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235384AbjG1KCw (ORCPT ); Fri, 28 Jul 2023 06:02:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233106AbjG1KC3 (ORCPT ); Fri, 28 Jul 2023 06:02:29 -0400 Received: from cloudserver094114.home.pl (cloudserver094114.home.pl [79.96.170.134]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2924049C4; Fri, 28 Jul 2023 03:01:58 -0700 (PDT) Received: from localhost (127.0.0.1) (HELO v370.home.net.pl) by /usr/run/smtp (/usr/run/postfix/private/idea_relay_lmtp) via UNIX with SMTP (IdeaSmtpServer 5.2.0) id 392725c6ea6dcf7f; Fri, 28 Jul 2023 12:01:56 +0200 Authentication-Results: v370.home.net.pl; spf=softfail (domain owner discourages use of this host) smtp.mailfrom=rjwysocki.net (client-ip=195.136.19.94; helo=[195.136.19.94]; envelope-from=rjw@rjwysocki.net; receiver=) Received: from kreacher.localnet (unknown [195.136.19.94]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by v370.home.net.pl (Postfix) with ESMTPSA id 29317661E37; Fri, 28 Jul 2023 12:01:56 +0200 (CEST) From: "Rafael J. Wysocki" To: Linux PM Cc: LKML , Peter Zijlstra , Anna-Maria Behnsen , Frederic Weisbecker , Kajetan Puchalski Subject: [PATCH v2 3/3] cpuidle: teo: Drop utilized from struct teo_cpu Date: Fri, 28 Jul 2023 12:01:49 +0200 Message-ID: <8262074.T7Z3S40VBb@kreacher> In-Reply-To: <5707588.DvuYhMxLoT@kreacher> References: <5707588.DvuYhMxLoT@kreacher> MIME-Version: 1.0 X-CLIENT-IP: 195.136.19.94 X-CLIENT-HOSTNAME: 195.136.19.94 X-VADE-SPAMSTATE: clean X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedviedrieeigddvtdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfjqffogffrnfdpggftiffpkfenuceurghilhhouhhtmecuudehtdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvvefufffkjghfggfgtgesthfuredttddtjeenucfhrhhomhepfdftrghfrggvlhculfdrucghhihsohgtkhhifdcuoehrjhifsehrjhifhihsohgtkhhirdhnvghtqeenucggtffrrghtthgvrhhnpedvffeuiedtgfdvtddugeeujedtffetteegfeekffdvfedttddtuefhgeefvdejhfenucfkphepudelhedrudefiedrudelrdelgeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpeduleehrddufeeirdduledrleegpdhhvghlohepkhhrvggrtghhvghrrdhlohgtrghlnhgvthdpmhgrihhlfhhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqpdhnsggprhgtphhtthhopeeipdhrtghpthhtoheplhhinhhugidqphhmsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepphgvthgvrhiisehinhhfrhgruggvrggurdhorhhgpdhrtghpthhtoheprghnnhgrqdhmrghrihgrsehlihhnuhhtrhhonhhigidruggvpdhrtghpthhtohepfhhrvggu vghrihgtsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehkrghjvghtrghnrdhpuhgthhgrlhhskhhisegrrhhmrdgtohhm X-DCC--Metrics: v370.home.net.pl 1024; Body=6 Fuz1=6 Fuz2=6 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Rafael J. Wysocki Because the utilized field in struct teo_cpu is only used locally in teo_select(), replace it with a local variable in that function. No intentional functional impact. Signed-off-by: Rafael J. Wysocki --- drivers/cpuidle/governors/teo.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) Index: linux-pm/drivers/cpuidle/governors/teo.c =================================================================== --- linux-pm.orig/drivers/cpuidle/governors/teo.c +++ linux-pm/drivers/cpuidle/governors/teo.c @@ -187,7 +187,6 @@ struct teo_bin { * @next_recent_idx: Index of the next @recent_idx entry to update. * @recent_idx: Indices of bins corresponding to recent "intercepts". * @util_threshold: Threshold above which the CPU is considered utilized - * @utilized: Whether the last sleep on the CPU happened while utilized */ struct teo_cpu { s64 time_span_ns; @@ -197,7 +196,6 @@ struct teo_cpu { int next_recent_idx; int recent_idx[NR_RECENT]; unsigned long util_threshold; - bool utilized; }; static DEFINE_PER_CPU(struct teo_cpu, teo_cpus); @@ -366,6 +364,7 @@ static int teo_select(struct cpuidle_dri int idx0 = 0, idx = -1; bool alt_intercepts, alt_recent; ktime_t delta_tick; + bool cpu_utilized; s64 duration_ns; int i; @@ -390,13 +389,13 @@ static int teo_select(struct cpuidle_dri goto end; } - cpu_data->utilized = teo_cpu_is_utilized(dev->cpu, cpu_data); + cpu_utilized = teo_cpu_is_utilized(dev->cpu, cpu_data); /* * If the CPU is being utilized over the threshold and there are only 2 * states to choose from, the metrics need not be considered, so choose * the shallowest non-polling state and exit. */ - if (drv->state_count < 3 && cpu_data->utilized) { + if (drv->state_count < 3 && cpu_utilized) { /* The CPU is utilized, so assume a short idle duration. */ duration_ns = teo_middle_of_bin(0, drv); /* @@ -558,7 +557,7 @@ static int teo_select(struct cpuidle_dri * been stopped already and the shallower state's target residency is * not sufficiently large. */ - if (cpu_data->utilized) { + if (cpu_utilized) { s64 span_ns; i = teo_find_shallower_state(drv, dev, idx, duration_ns, true);