From patchwork Wed Aug 2 13:24:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13338176 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 E4AFEC001E0 for ; Wed, 2 Aug 2023 13:31:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234051AbjHBNbf (ORCPT ); Wed, 2 Aug 2023 09:31:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233444AbjHBNbc (ORCPT ); Wed, 2 Aug 2023 09:31:32 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B25D1BFD; Wed, 2 Aug 2023 06:31:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=JAEdkNYRa3AXqsFdc832avh6PD2FjtrGNGx2xJmd/wI=; b=fU6G3YXwQ34Cb1/wQwfYvcumtt LdxhBQ2iLVc8CMCboG1kI/Le/16V4MPrdeVKmPfbuURe5qbMWj5RjiOyNU+Nq4b8NQetB6dPC/SVx 0X/DZFYsbtW4wMTqAdyzw/kYkZpsK5CgMufWNDUJJgcUSYP7tdpOLysCSaq6mBykBA+mtFdznhE1U eYmf+IZ5Tjg5P2CQdVYTBGWwf9qDFsVZtjZ9rHW4cDBosVOdTLhEebk5G0ceo9nIDkSUXOSr9ixQ1 tJhwIjp4FFEyr8Y0BxmXi07xsYgMy/mVdfLiYz8L2Htb4dQxwMFUTu6VUQ4Zrq2K7ChqThiWnJ0gE ZhsV3++Q==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qRBwZ-00FxfC-21; Wed, 02 Aug 2023 13:31:17 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 12B0A300301; Wed, 2 Aug 2023 15:31:15 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id ECE022107D7E6; Wed, 2 Aug 2023 15:31:14 +0200 (CEST) Message-ID: <20230802132925.549643116@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Aug 2023 15:24:32 +0200 From: Peter Zijlstra To: anna-maria@linutronix.de, rafael@kernel.org, tglx@linutronix.de, frederic@kernel.org, gautham.shenoy@amd.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, daniel.lezcano@linaro.org, linux-pm@vger.kernel.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, kajetan.puchalski@arm.com Subject: [RFC][PATCH v2 1/5] tick/nohz: Introduce tick_get_sleep_length() References: <20230802132431.254614419@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Add a variant of tick_nohz_get_sleep_length() that conditionally does the NOHZ part. tick_get_sleep_length(false) returns the delta_next return value of tick_nohz_get_sleep_length(), while tick_get_sleep_length(true) returns the regular return of tick_nohz_get_sleep_length(). This allows eliding tick_nohz_next_event() -- which is going to be expensive with timer-pull. Signed-off-by: Peter Zijlstra (Intel) --- include/linux/tick.h | 5 +++++ kernel/time/tick-sched.c | 35 +++++++++++++++++++++++------------ 2 files changed, 28 insertions(+), 12 deletions(-) --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -136,6 +136,7 @@ extern void tick_nohz_irq_exit(void); extern bool tick_nohz_idle_got_tick(void); extern ktime_t tick_nohz_get_next_hrtimer(void); extern ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next); +extern ktime_t tick_get_sleep_length(bool nohz); extern unsigned long tick_nohz_get_idle_calls(void); extern unsigned long tick_nohz_get_idle_calls_cpu(int cpu); extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time); @@ -168,6 +169,10 @@ static inline ktime_t tick_nohz_get_slee *delta_next = TICK_NSEC; return *delta_next; } +static inline ktime_t tick_get_sleep_length(bool nohz) +{ + return TICK_NSEC; +} static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; } static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; } --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -1218,17 +1218,7 @@ ktime_t tick_nohz_get_next_hrtimer(void) return __this_cpu_read(tick_cpu_device.evtdev)->next_event; } -/** - * tick_nohz_get_sleep_length - return the expected length of the current sleep - * @delta_next: duration until the next event if the tick cannot be stopped - * - * Called from power state control code with interrupts disabled. - * - * The return value of this function and/or the value returned by it through the - * @delta_next pointer can be negative which must be taken into account by its - * callers. - */ -ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next) +static ktime_t __tick_nohz_get_sleep_length(ktime_t *delta_next, bool nohz) { struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); @@ -1244,7 +1234,7 @@ ktime_t tick_nohz_get_sleep_length(ktime *delta_next = ktime_sub(dev->next_event, now); - if (!can_stop_idle_tick(cpu, ts)) + if (!nohz || !can_stop_idle_tick(cpu, ts)) return *delta_next; next_event = tick_nohz_next_event(ts, cpu); @@ -1262,6 +1252,27 @@ ktime_t tick_nohz_get_sleep_length(ktime } /** + * tick_nohz_get_sleep_length - return the expected length of the current sleep + * @delta_next: duration until the next event if the tick cannot be stopped + * + * Called from power state control code with interrupts disabled. + * + * The return value of this function and/or the value returned by it through the + * @delta_next pointer can be negative which must be taken into account by its + * callers. + */ +ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next) +{ + return __tick_nohz_get_sleep_length(delta_next, true); +} + +ktime_t tick_get_sleep_length(bool nohz) +{ + ktime_t delta; + return __tick_nohz_get_sleep_length(&delta, nohz); +} + +/** * tick_nohz_get_idle_calls_cpu - return the current idle calls counter value * for a particular CPU. * From patchwork Wed Aug 2 13:24:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13338173 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 7E15FC001E0 for ; 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Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1qRBwZ-00FBnW-JB; Wed, 02 Aug 2023 13:31:15 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 173A03006E2; Wed, 2 Aug 2023 15:31:15 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id EF6922066B201; Wed, 2 Aug 2023 15:31:14 +0200 (CEST) Message-ID: <20230802132925.618923837@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Aug 2023 15:24:33 +0200 From: Peter Zijlstra To: anna-maria@linutronix.de, rafael@kernel.org, tglx@linutronix.de, frederic@kernel.org, gautham.shenoy@amd.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, daniel.lezcano@linaro.org, linux-pm@vger.kernel.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, kajetan.puchalski@arm.com Subject: [RFC][PATCH v2 2/5] cpuidle: Inject tick boundary state References: <20230802132431.254614419@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org In order to facilitate governors that track history in idle-state buckets (TEO) making a useful decision about NOHZ, make sure we have a bucket that counts tick-and-longer. In order to be inclusive of the tick itself -- after all, if we do not disable NOHZ we'll sleep for a full tick, the actual boundary should be just short of a full tick. IOW, when registering the idle-states, add one that is always disabled, just to have a bucket. Signed-off-by: Peter Zijlstra (Intel) --- drivers/cpuidle/cpuidle.h | 2 + drivers/cpuidle/driver.c | 48 +++++++++++++++++++++++++++++++++++++++++++++- include/linux/cpuidle.h | 2 - 3 files changed, 50 insertions(+), 2 deletions(-) --- a/drivers/cpuidle/cpuidle.h +++ b/drivers/cpuidle/cpuidle.h @@ -72,4 +72,6 @@ static inline void cpuidle_coupled_unreg } #endif +#define SHORT_TICK_NSEC (TICK_NSEC - TICK_NSEC/32) + #endif /* __DRIVER_CPUIDLE_H */ --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -147,13 +147,37 @@ static void cpuidle_setup_broadcast_time tick_broadcast_disable(); } +static int tick_enter(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + return -ENODEV; +} + +static void __cpuidle_state_init_tick(struct cpuidle_state *s) +{ + strcpy(s->name, "TICK"); + strcpy(s->desc, "(no-op)"); + + s->target_residency_ns = SHORT_TICK_NSEC; + s->target_residency = div_u64(SHORT_TICK_NSEC, NSEC_PER_USEC); + + s->exit_latency_ns = 0; + s->exit_latency = 0; + + s->flags |= CPUIDLE_FLAG_UNUSABLE; + + s->enter = tick_enter; + s->enter_s2idle = tick_enter; +} + /** * __cpuidle_driver_init - initialize the driver's internal data * @drv: a valid pointer to a struct cpuidle_driver */ static void __cpuidle_driver_init(struct cpuidle_driver *drv) { - int i; + int tick = 0, i; /* * Use all possible CPUs as the default, because if the kernel boots @@ -163,6 +187,9 @@ static void __cpuidle_driver_init(struct if (!drv->cpumask) drv->cpumask = (struct cpumask *)cpu_possible_mask; + if (WARN_ON_ONCE(drv->state_count >= CPUIDLE_STATE_MAX-2)) + tick = 1; + for (i = 0; i < drv->state_count; i++) { struct cpuidle_state *s = &drv->states[i]; @@ -192,6 +219,25 @@ static void __cpuidle_driver_init(struct s->exit_latency_ns = 0; else s->exit_latency = div_u64(s->exit_latency_ns, NSEC_PER_USEC); + + if (!tick && s->target_residency_ns >= SHORT_TICK_NSEC) { + tick = 1; + + if (s->target_residency_ns == SHORT_TICK_NSEC) + continue; + + memmove(&drv->states[i+1], &drv->states[i], + sizeof(struct cpuidle_state) * (CPUIDLE_STATE_MAX - i - 1)); + __cpuidle_state_init_tick(s); + drv->state_count++; + i++; + } + } + + if (!tick) { + struct cpuidle_state *s = &drv->states[i]; + __cpuidle_state_init_tick(s); + drv->state_count++; } } --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -16,7 +16,7 @@ #include #include -#define CPUIDLE_STATE_MAX 10 +#define CPUIDLE_STATE_MAX 16 #define CPUIDLE_NAME_LEN 16 #define CPUIDLE_DESC_LEN 32 From patchwork Wed Aug 2 13:24:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13338177 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 B79D2C04A6A for ; Wed, 2 Aug 2023 13:31:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233127AbjHBNbi (ORCPT ); Wed, 2 Aug 2023 09:31:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59590 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233772AbjHBNbe (ORCPT ); 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Wed, 02 Aug 2023 13:31:16 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 1942E300768; Wed, 2 Aug 2023 15:31:15 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 00BDA2107D7E7; Wed, 2 Aug 2023 15:31:14 +0200 (CEST) Message-ID: <20230802132925.686745535@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Aug 2023 15:24:34 +0200 From: Peter Zijlstra To: anna-maria@linutronix.de, rafael@kernel.org, tglx@linutronix.de, frederic@kernel.org, gautham.shenoy@amd.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, daniel.lezcano@linaro.org, linux-pm@vger.kernel.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, kajetan.puchalski@arm.com Subject: [RFC][PATCH v2 3/5] cpuidle/teo: Simplify a little References: <20230802132431.254614419@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Remove some of the early exit cases that rely on state_count, since we have the additional tick state. Declutters some of the next patches, can possibly be re-instated later if desired. Signed-off-by: Peter Zijlstra (Intel) --- drivers/cpuidle/governors/teo.c | 31 +------------------------------ 1 file changed, 1 insertion(+), 30 deletions(-) --- a/drivers/cpuidle/governors/teo.c +++ b/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); @@ -379,33 +377,6 @@ static int teo_select(struct cpuidle_dri duration_ns = tick_nohz_get_sleep_length(&delta_tick); cpu_data->sleep_length_ns = duration_ns; - /* Check if there is any choice in the first place. */ - if (drv->state_count < 2) { - idx = 0; - goto end; - } - if (!dev->states_usage[0].disable) { - idx = 0; - if (drv->states[1].target_residency_ns > duration_ns) - goto end; - } - - cpu_data->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) { - 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; - } - } - } - /* * Find the deepest idle state whose target residency does not exceed * the current sleep length and the deepest idle state not deeper than @@ -541,7 +512,7 @@ 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 */ - if (cpu_data->utilized) + if (teo_cpu_is_utilized(dev->cpu, cpu_data)) idx = teo_find_shallower_state(drv, dev, idx, duration_ns, true); end: From patchwork Wed Aug 2 13:24:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13338174 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 39C8CC04A6A for ; Wed, 2 Aug 2023 13:31:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231612AbjHBNbd (ORCPT ); Wed, 2 Aug 2023 09:31:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233127AbjHBNbc (ORCPT ); Wed, 2 Aug 2023 09:31:32 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B2B02690; Wed, 2 Aug 2023 06:31:31 -0700 (PDT) DKIM-Signature: v=1; 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Wed, 2 Aug 2023 15:31:15 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 0527D2107D7E5; Wed, 2 Aug 2023 15:31:15 +0200 (CEST) Message-ID: <20230802132925.755164086@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Aug 2023 15:24:35 +0200 From: Peter Zijlstra To: anna-maria@linutronix.de, rafael@kernel.org, tglx@linutronix.de, frederic@kernel.org, gautham.shenoy@amd.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, daniel.lezcano@linaro.org, linux-pm@vger.kernel.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, kajetan.puchalski@arm.com Subject: [RFC][PATCH v2 4/5] cpuidle/teo: Avoid tick_nohz_next_event() References: <20230802132431.254614419@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Use the new tick_get_sleep_length() call in conjunction with the new TICK state to elide tick_nohz_next_event() when possible. Specifically, start the state selection using the existing next timer (tick or earlier). And only when state selection lands on the TICK state ask for the NOHZ next timer. Signed-off-by: Peter Zijlstra (Intel) --- drivers/cpuidle/governors/teo.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) --- a/drivers/cpuidle/governors/teo.c +++ b/drivers/cpuidle/governors/teo.c @@ -139,6 +139,7 @@ #include #include #include +#include "../cpuidle.h" /* * The number of bits to shift the CPU's capacity by in order to determine @@ -363,8 +364,7 @@ static int teo_select(struct cpuidle_dri int constraint_idx = 0; int idx0 = 0, idx = -1; bool alt_intercepts, alt_recent; - ktime_t delta_tick; - s64 duration_ns; + s64 duration_ns, tick_ns; int i; if (dev->last_state_idx >= 0) { @@ -374,8 +374,7 @@ static int teo_select(struct cpuidle_dri cpu_data->time_span_ns = local_clock(); - duration_ns = tick_nohz_get_sleep_length(&delta_tick); - cpu_data->sleep_length_ns = duration_ns; + duration_ns = tick_ns = tick_get_sleep_length(false); /* * Find the deepest idle state whose target residency does not exceed @@ -407,6 +406,14 @@ static int teo_select(struct cpuidle_dri if (s->target_residency_ns > duration_ns) break; + if (s->target_residency_ns == SHORT_TICK_NSEC) { + /* + * We hit the tick state, see if it makes sense to + * disable the tick and go deeper still. + */ + duration_ns = tick_get_sleep_length(true); + } + idx = i; if (s->exit_latency_ns <= latency_req) @@ -417,6 +424,8 @@ static int teo_select(struct cpuidle_dri idx_recent_sum = recent_sum; } + cpu_data->sleep_length_ns = duration_ns; + /* Avoid unnecessary overhead. */ if (idx < 0) { idx = 0; /* No states enabled, must use 0. */ @@ -531,8 +540,8 @@ static int teo_select(struct cpuidle_dri * that. */ if (idx > idx0 && - drv->states[idx].target_residency_ns > delta_tick) - idx = teo_find_shallower_state(drv, dev, idx, delta_tick, false); + drv->states[idx].target_residency_ns > tick_ns) + idx = teo_find_shallower_state(drv, dev, idx, tick_ns, false); } return idx; From patchwork Wed Aug 2 13:24:36 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13338178 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 51CF5C04FE0 for ; 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Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1qRBwa-00FBnY-5G; Wed, 02 Aug 2023 13:31:16 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 56827300DCF; Wed, 2 Aug 2023 15:31:15 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 0788F2107D7EA; Wed, 2 Aug 2023 15:31:15 +0200 (CEST) Message-ID: <20230802132925.824393002@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Aug 2023 15:24:36 +0200 From: Peter Zijlstra To: anna-maria@linutronix.de, rafael@kernel.org, tglx@linutronix.de, frederic@kernel.org, gautham.shenoy@amd.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, daniel.lezcano@linaro.org, linux-pm@vger.kernel.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, kajetan.puchalski@arm.com Subject: [RFC][PATCH v2 5/5] cpuidle,teo: Improve state selection References: <20230802132431.254614419@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org When selecting a state, stop when history tells us 66% of recent idles were at or below our current state. Signed-off-by: Peter Zijlstra (Intel) --- drivers/cpuidle/governors/teo.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/cpuidle/governors/teo.c +++ b/drivers/cpuidle/governors/teo.c @@ -361,6 +361,7 @@ static int teo_select(struct cpuidle_dri unsigned int recent_sum = 0; unsigned int idx_hit_sum = 0; unsigned int hit_sum = 0; + unsigned int thresh_sum = 0; int constraint_idx = 0; int idx0 = 0, idx = -1; bool alt_intercepts, alt_recent; @@ -376,6 +377,8 @@ static int teo_select(struct cpuidle_dri duration_ns = tick_ns = tick_get_sleep_length(false); + thresh_sum = 2 * cpu_data->total / 3; /* 66% */ + /* * Find the deepest idle state whose target residency does not exceed * the current sleep length and the deepest idle state not deeper than @@ -406,6 +409,9 @@ static int teo_select(struct cpuidle_dri if (s->target_residency_ns > duration_ns) break; + if (intercept_sum + hit_sum > thresh_sum) + break; + if (s->target_residency_ns == SHORT_TICK_NSEC) { /* * We hit the tick state, see if it makes sense to