From patchwork Wed Jan 20 15:50:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lina Iyer X-Patchwork-Id: 367995 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05B7BC433DB for ; Wed, 20 Jan 2021 15:53:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BECC923381 for ; Wed, 20 Jan 2021 15:53:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732991AbhATPxM (ORCPT ); Wed, 20 Jan 2021 10:53:12 -0500 Received: from a1.mail.mailgun.net ([198.61.254.60]:12135 "EHLO a1.mail.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391147AbhATPvp (ORCPT ); Wed, 20 Jan 2021 10:51:45 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1611157884; h=Content-Transfer-Encoding: MIME-Version: References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=Au7S6xU1ZhfwUiSwKsWHZZP9ZAyTtKF3+PizlpHKsSY=; b=gIIq8OgRwzB0ScWfX5iVJO3wjSn7VReeMo9TqodcfySj/ZUnGhgi1XN94ejQbDBSoxuIIUWu Bss2a+a8sXViNK1MTPm/eDEeQlNfp9fGZOYKeh9gbrNVHvO6kdes9PNTpEmqoxRoD1qe4Eay jwPJuAC4VpJyb+ZtXEZo2wxsN2w= X-Mailgun-Sending-Ip: 198.61.254.60 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n02.prod.us-west-2.postgun.com with SMTP id 600851585677aca7bd0e846d (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 20 Jan 2021 15:50:48 GMT Sender: ilina=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 51A82C433ED; Wed, 20 Jan 2021 15:50:48 +0000 (UTC) Received: from codeaurora.org (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: ilina) by smtp.codeaurora.org (Postfix) with ESMTPSA id 31E07C433C6; Wed, 20 Jan 2021 15:50:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 31E07C433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=ilina@codeaurora.org From: Lina Iyer To: ulf.hansson@linaro.org, rjw@rjwysocki.net Cc: linux-pm@vger.kernel.org, linux-arm-msm@vger.kernel.org, Lina Iyer Subject: [PATCH v9 1/2] PM / domains: inform PM domain of a device's next wakeup Date: Wed, 20 Jan 2021 08:50:41 -0700 Message-Id: <20210120155042.28975-2-ilina@codeaurora.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210120155042.28975-1-ilina@codeaurora.org> References: <20210120155042.28975-1-ilina@codeaurora.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Some devices may have a predictable interrupt pattern while executing usecases. An example would be the VSYNC interrupt associated with display devices. A 60 Hz display could cause a interrupt every 16 ms. If the device were in a PM domain, the domain would need to be powered up for device to resume and handle the interrupt. Entering a domain idle state saves power, only if the residency of the idle state is met. Without knowing the idle duration of the domain, the governor would just choose the deepest idle state that matches the QoS requirements. The domain might be powered off just as the device is expecting to wake up. If devices could inform PM frameworks of their next event, the parent PM domain's idle duration can be determined. So let's add the dev_pm_genpd_set_next_wakeup() API for the device to inform PM domains of the impending wakeup. This information will be the domain governor to determine the best idle state given the wakeup. Signed-off-by: Lina Iyer Reviewed-by: Ulf Hansson --- Changes in v9: - Check if device is part of genpd. Changes in v8: - Update documentation. Add Reviewed-by tag. Changes in v7: - Simplify and set next-wakeup locklessly Changes in v6: - Update documentation Changes in v5: - Fix commit text as pointed by Ulf - Use -EOPNOTSUPP Changes in v4: - Use PM domain data to store next_wakeup - Drop runtime PM documentation Changes in v3: - Fix unwanted change Changes in v2: - Update documentation - Remove runtime PM enabled check - Update commit text --- drivers/base/power/domain.c | 30 ++++++++++++++++++++++++++++++ include/linux/pm_domain.h | 6 ++++++ 2 files changed, 36 insertions(+) diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index 9a14eedacb92..014033c7c287 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -423,6 +423,35 @@ int dev_pm_genpd_set_performance_state(struct device *dev, unsigned int state) } EXPORT_SYMBOL_GPL(dev_pm_genpd_set_performance_state); +/** + * dev_pm_genpd_set_next_wakeup - Notify PM framework of an impending wakeup. + * + * @dev: Device to handle + * @next: impending interrupt/wakeup for the device + * + * + * Allow devices to inform of the next wakeup. It's assumed that the users + * guarantee that the genpd wouldn't be detached while this routine is getting + * called. Additionally, it's also assumed that @dev isn't runtime suspended + * (RPM_SUSPENDED)." + * Although devices are expected to update the next_wakeup after the end of + * their usecase as well, it is possible the devices themselves may not know + * about that, so stale @next will be ignored when powering off the domain. + */ +void dev_pm_genpd_set_next_wakeup(struct device *dev, ktime_t next) +{ + struct generic_pm_domain_data *gpd_data; + struct generic_pm_domain *genpd; + + genpd = dev_to_genpd_safe(dev); + if (!genpd) + return; + + gpd_data = to_gpd_data(dev->power.subsys_data->domain_data); + gpd_data->next_wakeup = next; +} +EXPORT_SYMBOL_GPL(dev_pm_genpd_set_next_wakeup); + static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed) { unsigned int state_idx = genpd->state_idx; @@ -1465,6 +1494,7 @@ static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev) gpd_data->td.constraint_changed = true; gpd_data->td.effective_constraint_ns = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS; gpd_data->nb.notifier_call = genpd_dev_pm_qos_notifier; + gpd_data->next_wakeup = KTIME_MAX; spin_lock_irq(&dev->power.lock); diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index 2ca919ae8d36..735583c0bc6d 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -9,6 +9,7 @@ #define _LINUX_PM_DOMAIN_H #include +#include #include #include #include @@ -191,6 +192,7 @@ struct generic_pm_domain_data { struct notifier_block *power_nb; int cpu; unsigned int performance_state; + ktime_t next_wakeup; void *data; }; @@ -217,6 +219,7 @@ int pm_genpd_remove(struct generic_pm_domain *genpd); int dev_pm_genpd_set_performance_state(struct device *dev, unsigned int state); int dev_pm_genpd_add_notifier(struct device *dev, struct notifier_block *nb); int dev_pm_genpd_remove_notifier(struct device *dev); +void dev_pm_genpd_set_next_wakeup(struct device *dev, ktime_t next); extern struct dev_power_governor simple_qos_governor; extern struct dev_power_governor pm_domain_always_on_gov; @@ -275,6 +278,9 @@ static inline int dev_pm_genpd_remove_notifier(struct device *dev) return -EOPNOTSUPP; } +static inline void dev_pm_genpd_set_next_wakeup(struct device *dev, ktime_t next) +{ } + #define simple_qos_governor (*(struct dev_power_governor *)(NULL)) #define pm_domain_always_on_gov (*(struct dev_power_governor *)(NULL)) #endif From patchwork Wed Jan 20 15:50:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lina Iyer X-Patchwork-Id: 367182 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D665FC433E0 for ; Wed, 20 Jan 2021 15:53:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A215323381 for ; Wed, 20 Jan 2021 15:53:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733099AbhATPxU (ORCPT ); Wed, 20 Jan 2021 10:53:20 -0500 Received: from a1.mail.mailgun.net ([198.61.254.60]:61461 "EHLO a1.mail.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391170AbhATPwC (ORCPT ); Wed, 20 Jan 2021 10:52:02 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1611157904; h=Content-Transfer-Encoding: MIME-Version: References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=dMLbNJEGXzoM679Q50OxCv2q5Q2UInHzraIg7p9pWgs=; b=UJtLeX/+sm+30nZhTskxI1Ts/hgFvOQCrU3tG19Hv+r79MRtpFyKg0d7wxt+HkHhfE5kF21Q ot4JXW1KNfwB/3cUMa+9RnFZsqjBzmAWFQWFcOe5RnMCrEE1BBoZgBmx7sBwG+07ri3wilYc 6aJDoQ4kCCAWapbdtZp8A/u71wc= X-Mailgun-Sending-Ip: 198.61.254.60 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-east-1.postgun.com with SMTP id 6008515a2c36b2106d706e1d (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 20 Jan 2021 15:50:50 GMT Sender: ilina=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 5B3ADC43461; Wed, 20 Jan 2021 15:50:49 +0000 (UTC) Received: from codeaurora.org (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: ilina) by smtp.codeaurora.org (Postfix) with ESMTPSA id 1A261C433CA; Wed, 20 Jan 2021 15:50:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 1A261C433CA Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=ilina@codeaurora.org From: Lina Iyer To: ulf.hansson@linaro.org, rjw@rjwysocki.net Cc: linux-pm@vger.kernel.org, linux-arm-msm@vger.kernel.org, Lina Iyer Subject: [PATCH v9 2/2] PM / Domains: use device's next wakeup to determine domain idle state Date: Wed, 20 Jan 2021 08:50:42 -0700 Message-Id: <20210120155042.28975-3-ilina@codeaurora.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210120155042.28975-1-ilina@codeaurora.org> References: <20210120155042.28975-1-ilina@codeaurora.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Currently, a PM domain's idle state is determined based on whether the QoS requirements are met. However, even entering an idle state may waste power if the minimum residency requirements aren't fulfilled. CPU PM domains use the next timer wakeup for the CPUs in the domain to determine the sleep duration of the domain. This is compared with the idle state residencies to determine the optimal idle state. For other PM domains, determining the sleep length is not that straight forward. But if the device's next_event is available, we can use that to determine the sleep duration of the PM domain. Let's update the domain governor logic to check for idle state residency based on the next wakeup of devices as well as QoS constraints. But since, not all domains may contain devices capable of specifying the next wakeup, let's enable this additional check only if specified by the domain's flags when initializing the domain. Signed-off-by: Lina Iyer Reviewed-by: Ulf Hansson --- Changes in v9: - None. Changes in v8: - Whitespace fixes and added reviewed-by tag Changes in v7: - Define GENPD_FLAG_MIN_RESIDENCY and check for min residency only if the flag is set. - Update commit text. Changes in v6: - Do not include power_on_latency_ns for next_wakeup determination. - Re-organize code to avoid multiple ktime_get() reads. - Check genpd flag if next_wakeup is useful for the domain. - Document why we ignore stale data Changes in v5: - Minor code changes suggested by Rafel Changes in v4: - Update to use next_wakeup from struct generic_pm_domain_data. Changes in v3: - None Changes in v2: - Fix state_idx type to hold negative value. - Update commit text. --- drivers/base/power/domain_governor.c | 102 ++++++++++++++++++++++++--- include/linux/pm_domain.h | 6 ++ 2 files changed, 99 insertions(+), 9 deletions(-) diff --git a/drivers/base/power/domain_governor.c b/drivers/base/power/domain_governor.c index 490ed7deb99a..c6c218758f0b 100644 --- a/drivers/base/power/domain_governor.c +++ b/drivers/base/power/domain_governor.c @@ -117,6 +117,55 @@ static bool default_suspend_ok(struct device *dev) return td->cached_suspend_ok; } +static void update_domain_next_wakeup(struct generic_pm_domain *genpd, ktime_t now) +{ + ktime_t domain_wakeup = KTIME_MAX; + ktime_t next_wakeup; + struct pm_domain_data *pdd; + struct gpd_link *link; + + if (!(genpd->flags & GENPD_FLAG_MIN_RESIDENCY)) + return; + + /* + * Devices that have a predictable wakeup pattern, may specify + * their next wakeup. Let's find the next wakeup from all the + * devices attached to this domain and from all the sub-domains. + * It is possible that component's a next wakeup may have become + * stale when we read that here. We will ignore to ensure the domain + * is able to enter its optimal idle state. + */ + list_for_each_entry(pdd, &genpd->dev_list, list_node) { + next_wakeup = to_gpd_data(pdd)->next_wakeup; + if (next_wakeup != KTIME_MAX && !ktime_before(next_wakeup, now)) + if (ktime_before(next_wakeup, domain_wakeup)) + domain_wakeup = next_wakeup; + } + + list_for_each_entry(link, &genpd->parent_links, parent_node) { + next_wakeup = link->child->next_wakeup; + if (next_wakeup != KTIME_MAX && !ktime_before(next_wakeup, now)) + if (ktime_before(next_wakeup, domain_wakeup)) + domain_wakeup = next_wakeup; + } + + genpd->next_wakeup = domain_wakeup; +} + +static bool next_wakeup_allows_state(struct generic_pm_domain *genpd, + unsigned int state, ktime_t now) +{ + ktime_t domain_wakeup = genpd->next_wakeup; + s64 idle_time_ns, min_sleep_ns; + + min_sleep_ns = genpd->states[state].power_off_latency_ns + + genpd->states[state].residency_ns; + + idle_time_ns = ktime_to_ns(ktime_sub(domain_wakeup, now)); + + return idle_time_ns >= min_sleep_ns; +} + static bool __default_power_down_ok(struct dev_pm_domain *pd, unsigned int state) { @@ -201,16 +250,41 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd, } /** - * default_power_down_ok - Default generic PM domain power off governor routine. + * _default_power_down_ok - Default generic PM domain power off governor routine. * @pd: PM domain to check. * * This routine must be executed under the PM domain's lock. */ -static bool default_power_down_ok(struct dev_pm_domain *pd) +static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now) { struct generic_pm_domain *genpd = pd_to_genpd(pd); + int state_idx = genpd->state_count - 1; struct gpd_link *link; + /* + * Find the next wakeup from devices that can determine their own wakeup + * to find when the domain would wakeup and do it for every device down + * the hierarchy. It is not worth while to sleep if the state's residency + * cannot be met. + */ + update_domain_next_wakeup(genpd, now); + if ((genpd->flags & GENPD_FLAG_MIN_RESIDENCY) && (genpd->next_wakeup != KTIME_MAX)) { + /* Let's find out the deepest domain idle state, the devices prefer */ + while (state_idx >= 0) { + if (next_wakeup_allows_state(genpd, state_idx, now)) { + genpd->max_off_time_changed = true; + break; + } + state_idx--; + } + + if (state_idx < 0) { + state_idx = 0; + genpd->cached_power_down_ok = false; + goto done; + } + } + if (!genpd->max_off_time_changed) { genpd->state_idx = genpd->cached_power_down_state_idx; return genpd->cached_power_down_ok; @@ -228,21 +302,30 @@ static bool default_power_down_ok(struct dev_pm_domain *pd) genpd->max_off_time_ns = -1; genpd->max_off_time_changed = false; genpd->cached_power_down_ok = true; - genpd->state_idx = genpd->state_count - 1; - /* Find a state to power down to, starting from the deepest. */ - while (!__default_power_down_ok(pd, genpd->state_idx)) { - if (genpd->state_idx == 0) { + /* + * Find a state to power down to, starting from the state + * determined by the next wakeup. + */ + while (!__default_power_down_ok(pd, state_idx)) { + if (state_idx == 0) { genpd->cached_power_down_ok = false; break; } - genpd->state_idx--; + state_idx--; } +done: + genpd->state_idx = state_idx; genpd->cached_power_down_state_idx = genpd->state_idx; return genpd->cached_power_down_ok; } +static bool default_power_down_ok(struct dev_pm_domain *pd) +{ + return _default_power_down_ok(pd, ktime_get()); +} + static bool always_on_power_down_ok(struct dev_pm_domain *domain) { return false; @@ -254,11 +337,12 @@ static bool cpu_power_down_ok(struct dev_pm_domain *pd) struct generic_pm_domain *genpd = pd_to_genpd(pd); struct cpuidle_device *dev; ktime_t domain_wakeup, next_hrtimer; + ktime_t now = ktime_get(); s64 idle_duration_ns; int cpu, i; /* Validate dev PM QoS constraints. */ - if (!default_power_down_ok(pd)) + if (!_default_power_down_ok(pd, now)) return false; if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN)) @@ -280,7 +364,7 @@ static bool cpu_power_down_ok(struct dev_pm_domain *pd) } /* The minimum idle duration is from now - until the next wakeup. */ - idle_duration_ns = ktime_to_ns(ktime_sub(domain_wakeup, ktime_get())); + idle_duration_ns = ktime_to_ns(ktime_sub(domain_wakeup, now)); if (idle_duration_ns <= 0) return false; diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index 735583c0bc6d..dfcfbcecc34b 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -56,6 +56,10 @@ * * GENPD_FLAG_RPM_ALWAYS_ON: Instructs genpd to always keep the PM domain * powered on except for system suspend. + * + * GENPD_FLAG_MIN_RESIDENCY: Enable the genpd governor to consider its + * components' next wakeup when determining the + * optimal idle state. */ #define GENPD_FLAG_PM_CLK (1U << 0) #define GENPD_FLAG_IRQ_SAFE (1U << 1) @@ -63,6 +67,7 @@ #define GENPD_FLAG_ACTIVE_WAKEUP (1U << 3) #define GENPD_FLAG_CPU_DOMAIN (1U << 4) #define GENPD_FLAG_RPM_ALWAYS_ON (1U << 5) +#define GENPD_FLAG_MIN_RESIDENCY (1U << 6) enum gpd_status { GENPD_STATE_ON = 0, /* PM domain is on */ @@ -130,6 +135,7 @@ struct generic_pm_domain { unsigned int state); struct gpd_dev_ops dev_ops; s64 max_off_time_ns; /* Maximum allowed "suspended" time. */ + ktime_t next_wakeup; /* Maintained by the domain governor */ bool max_off_time_changed; bool cached_power_down_ok; bool cached_power_down_state_idx;