From patchwork Fri Feb 12 20:50:33 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lina Iyer X-Patchwork-Id: 8297541 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 992AF9F372 for ; Fri, 12 Feb 2016 20:56:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 662802044B for ; Fri, 12 Feb 2016 20:56:37 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 661F2203F4 for ; Fri, 12 Feb 2016 20:56:36 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1aUKju-00011I-Vy; Fri, 12 Feb 2016 20:54:55 +0000 Received: from mail-pf0-x22d.google.com ([2607:f8b0:400e:c00::22d]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1aUKh0-0006Vb-1w for linux-arm-kernel@lists.infradead.org; Fri, 12 Feb 2016 20:51:56 +0000 Received: by mail-pf0-x22d.google.com with SMTP id e127so53012944pfe.3 for ; Fri, 12 Feb 2016 12:51:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=2nW23DI9q6WL3rmC9BRWwucCbKSeoB+WDPeFI9hp6lw=; b=bAABZxlZvRpGVOOElNSO865Uu7ldFtVsDAaPaUkQXEoZzPGN858/lPe1MyA+IoV29F QSJLy6aSo747i0GXp8reHx2PAa+ozVykFxCYid9THcg/lCZaE4E8ms+rDYi0HUdtVWdT kuTNZRFrF2iSvOlQJFXYfjLw8dbMsJNrmMrQA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=2nW23DI9q6WL3rmC9BRWwucCbKSeoB+WDPeFI9hp6lw=; b=GvkVZwuadaCP/s7fneaYoBXzTtLN/cv1NEvpLpfCGM6qz5BemWw6uE+819L6dRZxjX Ov+sTLd2/+j1OtygOKdOlypf83CvN90omBQ3F5ayqeYknu4Jf+V4T1KwCYUoTp1hvXLn lIGZLn+mWHcjhn5hQbT1weEtfylOYTTWCDdbAxI4m3H90PhZHS0XJEM+DbON8R98t0f/ zouqyq31kJPUnxSfCnduwBhbfGJDC0LtPkJaOlzQsIu9cf1TrPrizlq3NUWY+jXC6ic8 jSHb8afX5lvgFjg79koKu9dWUg0phL1fsuVxDMETsutmBQrXzPjS8zst/07weZaTInDz KkRg== X-Gm-Message-State: AG10YOT3FICMDmXha41/07oL2gtdtytiXJDnDepDDDypvXGyEwODRLeWmVbTfFy81NtDau0m X-Received: by 10.98.14.79 with SMTP id w76mr5121247pfi.1.1455310293204; Fri, 12 Feb 2016 12:51:33 -0800 (PST) Received: from ubuntu.localdomain ([172.56.8.98]) by smtp.gmail.com with ESMTPSA id x12sm21401070pfi.88.2016.02.12.12.51.30 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 12 Feb 2016 12:51:32 -0800 (PST) From: Lina Iyer To: ulf.hansson@linaro.org, khilman@kernel.org, rjw@rjwysocki.net, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [RFC v2 07/12] PM / cpu_domains: Add PM Domain governor for CPUs Date: Fri, 12 Feb 2016 13:50:33 -0700 Message-Id: <1455310238-8963-8-git-send-email-lina.iyer@linaro.org> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1455310238-8963-1-git-send-email-lina.iyer@linaro.org> References: <1455310238-8963-1-git-send-email-lina.iyer@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160212_125154_317094_8FC86ED2 X-CRM114-Status: GOOD ( 18.93 ) X-Spam-Score: -2.7 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: k.kozlowski@samsung.com, lorenzo.pieralisi@arm.com, ahaslam@baylibre.com, linux-arm-msm@vger.kernel.org, sboyd@codeaurora.org, msivasub@codeaurora.org, geert@linux-m68k.org, Lina Iyer , agross@codeaurora.org, mtitinger@baylibre.com MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP A PM domain comprising of CPUs may be powered off when all the CPUs in the domain are powered down. Powering down a CPU domain is generally a expensive operation and therefore the power performance trade offs should be considered. The time between the last CPU powering down and the first CPU powering up in a domain, is the time available for the domain to sleep. Ideally, the sleep time of the domain should fulfill the residency requirement of the domains' idle state. To do this effectively, read the time before the wakeup of the cluster's CPUs and ensure that the domain's idle state sleep time guarantees the QoS requirements of each of the CPU, the PM QoS CPU_DMA_LATENCY and the state's residency. Signed-off-by: Lina Iyer --- Changes since RFC v1 - - bug fix drivers/base/power/cpu_domains.c | 75 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 74 insertions(+), 1 deletion(-) diff --git a/drivers/base/power/cpu_domains.c b/drivers/base/power/cpu_domains.c index c99710c..7069411 100644 --- a/drivers/base/power/cpu_domains.c +++ b/drivers/base/power/cpu_domains.c @@ -17,9 +17,12 @@ #include #include #include +#include +#include #include #include #include +#include #define CPU_PD_NAME_MAX 36 @@ -52,6 +55,76 @@ struct cpu_pm_domain *to_cpu_pd(struct generic_pm_domain *d) return res; } +static bool cpu_pd_down_ok(struct dev_pm_domain *pd) +{ + struct generic_pm_domain *genpd = pd_to_genpd(pd); + struct cpu_pm_domain *cpu_pd = to_cpu_pd(genpd); + int qos = pm_qos_request(PM_QOS_CPU_DMA_LATENCY); + u64 sleep_ns; + ktime_t earliest, next_wakeup; + int cpu; + int i; + + /* Reset the last set genpd state, default to index 0 */ + genpd->state_idx = 0; + + /* We dont want to power down, if QoS is 0 */ + if (!qos) + return false; + + /* + * Find the sleep time for the cluster. + * The time between now and the first wake up of any CPU that + * are in this domain hierarchy is the time available for the + * domain to be idle. + */ + earliest = ktime_set(KTIME_SEC_MAX, 0); + for_each_cpu_and(cpu, cpu_pd->cpus, cpu_online_mask) { + next_wakeup = tick_nohz_get_next_wakeup(cpu); + if (earliest.tv64 > next_wakeup.tv64) + earliest = next_wakeup; + } + + sleep_ns = ktime_to_ns(ktime_sub(earliest, ktime_get())); + if (sleep_ns <= 0) + return false; + + /* + * Find the deepest sleep state that satisfies the residency + * requirement and the QoS constraint + */ + for (i = genpd->state_count - 1; i >= 0; i--) { + u64 state_sleep_ns; + + state_sleep_ns = genpd->states[i].power_off_latency_ns + + genpd->states[i].power_on_latency_ns + + genpd->states[i].residency_ns; + + /* + * If we cant sleep to save power in the state, move on + * to the next lower idle state. + */ + if (state_sleep_ns > sleep_ns) + continue; + + /* + * We also dont want to sleep more than we should to + * gaurantee QoS. + */ + if (state_sleep_ns < (qos * NSEC_PER_USEC)) + break; + } + + if (i >= 0) + genpd->state_idx = i; + + return (i >= 0) ? true : false; +} + +static struct dev_power_governor cpu_pd_gov = { + .power_down_ok = cpu_pd_down_ok, +}; + static int cpu_pd_attach_cpu(struct cpu_pm_domain *cpu_pd, int cpu) { int ret; @@ -143,7 +216,7 @@ static struct generic_pm_domain *of_init_cpu_pm_domain(struct device_node *dn, /* Register the CPU genpd */ pr_debug("adding %s as CPU PM domain.\n", pd->genpd->name); - ret = of_pm_genpd_init(dn, pd->genpd, &simple_qos_governor, false); + ret = of_pm_genpd_init(dn, pd->genpd, &cpu_pd_gov, false); if (ret) { pr_err("Unable to initialize domain %s\n", dn->full_name); goto fail;