From patchwork Fri Jan 31 16:24:36 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Beata Michalska X-Patchwork-Id: 13955488 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 009ADC0218F for ; Fri, 31 Jan 2025 16:27:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=CMdgtMp5JbeT+NP7AFchtYIhVI+01QBfXk5wimhhmQk=; b=GQshS/ogtqCDmrrysPoiQY/i43 i9+DBU4zmXFYBqeKrQx8ZDfRsFZQCy1VSd4stPGU/5AN0ipJCxU1ZPHReLS7BplUIvct0v5ngmo/c 6E1WksTT54ZqybpAXGg5KT8g2msh98Xx/pBnUZZSPivYu/qiIHG6wbWZSTNaar6ghcNgMxJeBJnuE KJQyJlLZVmNYQZMFULQYW0RTCwx63GFJxdLldrfsJ5IBa8nFvNUvE7vfkV0mu+RP0/uWpd2bpTxvO A9+TRxi+3WpQyHzJeUS9TjGpdDEHvsE7UdjlDO4hLEiDsqMDVHiqykgfU8zmQbEFTXiNfT5ILdTvO wObpUCOQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tdtrp-0000000AybL-0CYH; Fri, 31 Jan 2025 16:27:41 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tdtpF-0000000Ay1u-226y for linux-arm-kernel@lists.infradead.org; Fri, 31 Jan 2025 16:25:02 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5A386FEC; Fri, 31 Jan 2025 08:25:26 -0800 (PST) Received: from e125905.cambridge.arm.com (e125905.cambridge.arm.com [10.1.194.73]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D04363F694; Fri, 31 Jan 2025 08:24:58 -0800 (PST) From: Beata Michalska To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, ionela.voinescu@arm.com, sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, rafael@kernel.org, viresh.kumar@linaro.org Cc: sumitg@nvidia.com, yang@os.amperecomputing.com, vanshikonda@os.amperecomputing.com, lihuisong@huawei.com, zhanjie9@hisilicon.com, ptsm@linux.microsoft.com Subject: [PATCH v10 1/4] cpufreq: Allow arch_freq_get_on_cpu to return an error Date: Fri, 31 Jan 2025 16:24:36 +0000 Message-Id: <20250131162439.3843071-2-beata.michalska@arm.com> In-Reply-To: <20250131162439.3843071-1-beata.michalska@arm.com> References: <20250131162439.3843071-1-beata.michalska@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250131_082501_612958_3DADF5B8 X-CRM114-Status: GOOD ( 12.40 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Allow arch_freq_get_on_cpu to return an error for cases when retrieving current CPU frequency is not possible, whether that being due to lack of required arch support or due to other circumstances when the current frequency cannot be determined at given point of time. Signed-off-by: Beata Michalska Reviewed-by: Prasanna Kumar T S M --- arch/x86/kernel/cpu/aperfmperf.c | 2 +- arch/x86/kernel/cpu/proc.c | 7 +++++-- drivers/cpufreq/cpufreq.c | 8 ++++---- include/linux/cpufreq.h | 2 +- 4 files changed, 11 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c index f642de2ebdac..6cf31a1649c4 100644 --- a/arch/x86/kernel/cpu/aperfmperf.c +++ b/arch/x86/kernel/cpu/aperfmperf.c @@ -498,7 +498,7 @@ void arch_scale_freq_tick(void) */ #define MAX_SAMPLE_AGE ((unsigned long)HZ / 50) -unsigned int arch_freq_get_on_cpu(int cpu) +int arch_freq_get_on_cpu(int cpu) { struct aperfmperf *s = per_cpu_ptr(&cpu_samples, cpu); unsigned int seq, freq; diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c index 41ed01f46bd9..6571d432cbe3 100644 --- a/arch/x86/kernel/cpu/proc.c +++ b/arch/x86/kernel/cpu/proc.c @@ -86,9 +86,12 @@ static int show_cpuinfo(struct seq_file *m, void *v) seq_printf(m, "microcode\t: 0x%x\n", c->microcode); if (cpu_has(c, X86_FEATURE_TSC)) { - unsigned int freq = arch_freq_get_on_cpu(cpu); + int freq = arch_freq_get_on_cpu(cpu); - seq_printf(m, "cpu MHz\t\t: %u.%03u\n", freq / 1000, (freq % 1000)); + if (freq < 0) + seq_puts(m, "cpu MHz\t\t: Unknown\n"); + else + seq_printf(m, "cpu MHz\t\t: %u.%03u\n", freq / 1000, (freq % 1000)); } /* Cache size */ diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index e0048856ecee..96b013ea177c 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -729,18 +729,18 @@ show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); show_one(scaling_min_freq, min); show_one(scaling_max_freq, max); -__weak unsigned int arch_freq_get_on_cpu(int cpu) +__weak int arch_freq_get_on_cpu(int cpu) { - return 0; + return -EOPNOTSUPP; } static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf) { ssize_t ret; - unsigned int freq; + int freq; freq = arch_freq_get_on_cpu(policy->cpu); - if (freq) + if (freq > 0) ret = sysfs_emit(buf, "%u\n", freq); else if (cpufreq_driver->setpolicy && cpufreq_driver->get) ret = sysfs_emit(buf, "%u\n", cpufreq_driver->get(policy->cpu)); diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 7fe0981a7e46..02fd4746231d 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -1184,7 +1184,7 @@ static inline int of_perf_domain_get_sharing_cpumask(int pcpu, const char *list_ } #endif -extern unsigned int arch_freq_get_on_cpu(int cpu); +extern int arch_freq_get_on_cpu(int cpu); #ifndef arch_set_freq_scale static __always_inline From patchwork Fri Jan 31 16:24:37 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Beata Michalska X-Patchwork-Id: 13955489 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7B2DBC0218F for ; Fri, 31 Jan 2025 16:29:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=kMAbxwob+P+oW6SDLV/49Jbpbe4ZXebI43nReHt9G20=; b=D1+w9Q+v600ugtOivVwcrWc6xY DNzh2axkcpJaFcpPlUiqXf6NEAWQCn45DbHcB8JBh3mHEeFpnGcHHOUaO7fdvgdVEnZhdeOhr4fmk 3VR1BfPNldSlx72ce3w+RN9iVKd3S/b9PDvk1SqZ3IoPQJb85Jzuhux/IQ7iYale7L6jzOEfi9EXC j8mQXVh8U3a+QSiGV6k82YZSfXTMrpTYtKeC6jKdmkVPYVKAORn5F9sRsoTckIGqNcyjWntALAgov xOCSVQj8I/BhOLxU5u1Fyl5Ed+mOvs180wqR+/AD+9mwQXHXDKHic4PU0RnH3fJ5i847OJ9dR+Bnl ocs4c5hA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tdtt6-0000000Aynv-2pFH; Fri, 31 Jan 2025 16:29:00 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tdtpJ-0000000Ay46-1pSK for linux-arm-kernel@lists.infradead.org; Fri, 31 Jan 2025 16:25:06 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E744A150C; Fri, 31 Jan 2025 08:25:29 -0800 (PST) Received: from e125905.cambridge.arm.com (e125905.cambridge.arm.com [10.1.194.73]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 47BFC3F694; Fri, 31 Jan 2025 08:25:01 -0800 (PST) From: Beata Michalska To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, ionela.voinescu@arm.com, sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, rafael@kernel.org, viresh.kumar@linaro.org Cc: sumitg@nvidia.com, yang@os.amperecomputing.com, vanshikonda@os.amperecomputing.com, lihuisong@huawei.com, zhanjie9@hisilicon.com, ptsm@linux.microsoft.com, Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Phil Auld , x86@kernel.org, linux-doc@vger.kernel.org Subject: [PATCH v10 2/4] cpufreq: Introduce an optional cpuinfo_avg_freq sysfs entry Date: Fri, 31 Jan 2025 16:24:37 +0000 Message-Id: <20250131162439.3843071-3-beata.michalska@arm.com> In-Reply-To: <20250131162439.3843071-1-beata.michalska@arm.com> References: <20250131162439.3843071-1-beata.michalska@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250131_082505_562030_11893E9B X-CRM114-Status: GOOD ( 21.71 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Currently the CPUFreq core exposes two sysfs attributes that can be used to query current frequency of a given CPU(s): namely cpuinfo_cur_freq and scaling_cur_freq. Both provide slightly different view on the subject and they do come with their own drawbacks. cpuinfo_cur_freq provides higher precision though at a cost of being rather expensive. Moreover, the information retrieved via this attribute is somewhat short lived as frequency can change at any point of time making it difficult to reason from. scaling_cur_freq, on the other hand, tends to be less accurate but then the actual level of precision (and source of information) varies between architectures making it a bit ambiguous. The new attribute, cpuinfo_avg_freq, is intended to provide more stable, distinct interface, exposing an average frequency of a given CPU(s), as reported by the hardware, over a time frame spanning no more than a few milliseconds. As it requires appropriate hardware support, this interface is optional. Note that under the hood, the new attribute relies on the information provided by arch_freq_get_on_cpu, which, up to this point, has been feeding data for scaling_cur_freq attribute, being the source of ambiguity when it comes to interpretation. This has been amended by restoring the intended behavior for scaling_cur_freq, with a new dedicated config option to maintain status quo for those, who may need it. CC: Jonathan Corbet CC: Thomas Gleixner CC: Ingo Molnar CC: Borislav Petkov CC: Dave Hansen CC: H. Peter Anvin CC: Phil Auld CC: x86@kernel.org CC: linux-doc@vger.kernel.org Signed-off-by: Beata Michalska Reviewed-by: Prasanna Kumar T S M Reviewed-by: Sumit Gupta --- Documentation/admin-guide/pm/cpufreq.rst | 17 +++++++++++++- drivers/cpufreq/Kconfig.x86 | 12 ++++++++++ drivers/cpufreq/cpufreq.c | 30 +++++++++++++++++++++++- 3 files changed, 57 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/pm/cpufreq.rst b/Documentation/admin-guide/pm/cpufreq.rst index a21369eba034..3950583f2b15 100644 --- a/Documentation/admin-guide/pm/cpufreq.rst +++ b/Documentation/admin-guide/pm/cpufreq.rst @@ -248,6 +248,20 @@ are the following: If that frequency cannot be determined, this attribute should not be present. +``cpuinfo_avg_freq`` + An average frequency (in KHz) of all CPUs belonging to a given policy, + derived from a hardware provided feedback and reported on a time frame + spanning at most few milliseconds. + + This is expected to be based on the frequency the hardware actually runs + at and, as such, might require specialised hardware support (such as AMU + extension on ARM). If one cannot be determined, this attribute should + not be present. + + Note, that failed attempt to retrieve current frequency for a given + CPU(s) will result in an appropriate error, i.e: EAGAIN for CPU that + remains idle (raised on ARM). + ``cpuinfo_max_freq`` Maximum possible operating frequency the CPUs belonging to this policy can run at (in kHz). @@ -293,7 +307,8 @@ are the following: Some architectures (e.g. ``x86``) may attempt to provide information more precisely reflecting the current CPU frequency through this attribute, but that still may not be the exact current CPU frequency as - seen by the hardware at the moment. + seen by the hardware at the moment. This behavior though, is only + available via c:macro:``CPUFREQ_ARCH_CUR_FREQ`` option. ``scaling_driver`` The scaling driver currently in use. diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86 index 97c2d4f15d76..2c5c228408bf 100644 --- a/drivers/cpufreq/Kconfig.x86 +++ b/drivers/cpufreq/Kconfig.x86 @@ -340,3 +340,15 @@ config X86_SPEEDSTEP_RELAXED_CAP_CHECK option lets the probing code bypass some of those checks if the parameter "relaxed_check=1" is passed to the module. +config CPUFREQ_ARCH_CUR_FREQ + default y + bool "Current frequency derived from HW provided feedback" + help + This determines whether the scaling_cur_freq sysfs attribute returns + the last requested frequency or a more precise value based on hardware + provided feedback (as architected counters). + Given that a more precise frequency can now be provided via the + cpuinfo_avg_freq attribute, by enabling this option, + scaling_cur_freq maintains the provision of a counter based frequency, + for compatibility reasons. + diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 96b013ea177c..a2f31fbb1774 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -734,12 +734,20 @@ __weak int arch_freq_get_on_cpu(int cpu) return -EOPNOTSUPP; } +static inline bool cpufreq_avg_freq_supported(struct cpufreq_policy *policy) +{ + return arch_freq_get_on_cpu(policy->cpu) != -EOPNOTSUPP; +} + static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf) { ssize_t ret; int freq; - freq = arch_freq_get_on_cpu(policy->cpu); + freq = IS_ENABLED(CONFIG_CPUFREQ_ARCH_CUR_FREQ) + ? arch_freq_get_on_cpu(policy->cpu) + : 0; + if (freq > 0) ret = sysfs_emit(buf, "%u\n", freq); else if (cpufreq_driver->setpolicy && cpufreq_driver->get) @@ -784,6 +792,19 @@ static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy, return sysfs_emit(buf, "\n"); } +/* + * show_cpuinfo_avg_freq - average CPU frequency as detected by hardware + */ +static ssize_t show_cpuinfo_avg_freq(struct cpufreq_policy *policy, + char *buf) +{ + int avg_freq = arch_freq_get_on_cpu(policy->cpu); + + if (avg_freq > 0) + return sysfs_emit(buf, "%u\n", avg_freq); + return avg_freq != 0 ? avg_freq : -EINVAL; +} + /* * show_scaling_governor - show the current policy for the specified CPU */ @@ -946,6 +967,7 @@ static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf) } cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400); +cpufreq_freq_attr_ro(cpuinfo_avg_freq); cpufreq_freq_attr_ro(cpuinfo_min_freq); cpufreq_freq_attr_ro(cpuinfo_max_freq); cpufreq_freq_attr_ro(cpuinfo_transition_latency); @@ -1073,6 +1095,12 @@ static int cpufreq_add_dev_interface(struct cpufreq_policy *policy) return ret; } + if (cpufreq_avg_freq_supported(policy)) { + ret = sysfs_create_file(&policy->kobj, &cpuinfo_avg_freq.attr); + if (ret) + return ret; + } + ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); if (ret) return ret; From patchwork Fri Jan 31 16:24:38 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Beata Michalska X-Patchwork-Id: 13955553 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7DE69C0218F for ; Fri, 31 Jan 2025 16:30:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=A4wGvZD37FipvkN7a2zE8RZjeCNOx/Mg8hMp0PcY6LA=; b=gwzjrAYuyajCnVW2s2sL4ixAQp LvTFS1DtbII41awHC+DFVxLtMhMpK87gswGvgu4z7RlzQsGhsWEIDOf0JWj04AFJaIET0iRO2KO3z +9/34Isn25/QnmFDgfei4vRuHcXtrev6KgUN7WzF8pa9CXqdGqVPD9SogvlqA24ENZTbACEvF8rb2 v24Beg5tEkdrAMyrNVFpg5RVDs4LheAEvFoYmUFIA15ayHtKoY8qYyvig1pzB6YRmFCCei+0V01mg nJ8XXbPJOzrGKUNJ195492Wzr+G+CJx2fl6ACxOEze0bjF8RXUgN4+8E7cGx3umoNoDw/15EJ1GFi o1rbTpYQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tdtuN-0000000AyyB-1IBT; Fri, 31 Jan 2025 16:30:19 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tdtpL-0000000Ay53-1J0x for linux-arm-kernel@lists.infradead.org; Fri, 31 Jan 2025 16:25:08 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5A9C5168F; Fri, 31 Jan 2025 08:25:32 -0800 (PST) Received: from e125905.cambridge.arm.com (e125905.cambridge.arm.com [10.1.194.73]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D43033F694; Fri, 31 Jan 2025 08:25:04 -0800 (PST) From: Beata Michalska To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, ionela.voinescu@arm.com, sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, rafael@kernel.org, viresh.kumar@linaro.org Cc: sumitg@nvidia.com, yang@os.amperecomputing.com, vanshikonda@os.amperecomputing.com, lihuisong@huawei.com, zhanjie9@hisilicon.com, ptsm@linux.microsoft.com Subject: [PATCH v10 3/4] arm64: Provide an AMU-based version of arch_freq_get_on_cpu Date: Fri, 31 Jan 2025 16:24:38 +0000 Message-Id: <20250131162439.3843071-4-beata.michalska@arm.com> In-Reply-To: <20250131162439.3843071-1-beata.michalska@arm.com> References: <20250131162439.3843071-1-beata.michalska@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250131_082507_436005_10841187 X-CRM114-Status: GOOD ( 17.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org With the Frequency Invariance Engine (FIE) being already wired up with sched tick and making use of relevant (core counter and constant counter) AMU counters, getting the average frequency for a given CPU, can be achieved by utilizing the frequency scale factor which reflects an average CPU frequency for the last tick period length. The solution is partially based on APERF/MPERF implementation of arch_freq_get_on_cpu. Suggested-by: Ionela Voinescu Signed-off-by: Beata Michalska Reviewed-by: Prasanna Kumar T S M Reviewed-by: Sumit Gupta --- arch/arm64/kernel/topology.c | 112 +++++++++++++++++++++++++++++++---- 1 file changed, 102 insertions(+), 10 deletions(-) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index cb180684d10d..bd238e5c2133 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -88,18 +89,28 @@ int __init parse_acpi_topology(void) * initialized. */ static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, arch_max_freq_scale) = 1UL << (2 * SCHED_CAPACITY_SHIFT); -static DEFINE_PER_CPU(u64, arch_const_cycles_prev); -static DEFINE_PER_CPU(u64, arch_core_cycles_prev); static cpumask_var_t amu_fie_cpus; +struct amu_cntr_sample { + u64 arch_const_cycles_prev; + u64 arch_core_cycles_prev; + unsigned long last_scale_update; +}; + +static DEFINE_PER_CPU_SHARED_ALIGNED(struct amu_cntr_sample, cpu_amu_samples); + void update_freq_counters_refs(void) { - this_cpu_write(arch_core_cycles_prev, read_corecnt()); - this_cpu_write(arch_const_cycles_prev, read_constcnt()); + struct amu_cntr_sample *amu_sample = this_cpu_ptr(&cpu_amu_samples); + + amu_sample->arch_core_cycles_prev = read_corecnt(); + amu_sample->arch_const_cycles_prev = read_constcnt(); } static inline bool freq_counters_valid(int cpu) { + struct amu_cntr_sample *amu_sample = per_cpu_ptr(&cpu_amu_samples, cpu); + if ((cpu >= nr_cpu_ids) || !cpumask_test_cpu(cpu, cpu_present_mask)) return false; @@ -108,8 +119,8 @@ static inline bool freq_counters_valid(int cpu) return false; } - if (unlikely(!per_cpu(arch_const_cycles_prev, cpu) || - !per_cpu(arch_core_cycles_prev, cpu))) { + if (unlikely(!amu_sample->arch_const_cycles_prev || + !amu_sample->arch_core_cycles_prev)) { pr_debug("CPU%d: cycle counters are not enabled.\n", cpu); return false; } @@ -152,17 +163,22 @@ void freq_inv_set_max_ratio(int cpu, u64 max_rate) static void amu_scale_freq_tick(void) { + struct amu_cntr_sample *amu_sample = this_cpu_ptr(&cpu_amu_samples); u64 prev_core_cnt, prev_const_cnt; u64 core_cnt, const_cnt, scale; - prev_const_cnt = this_cpu_read(arch_const_cycles_prev); - prev_core_cnt = this_cpu_read(arch_core_cycles_prev); + prev_const_cnt = amu_sample->arch_const_cycles_prev; + prev_core_cnt = amu_sample->arch_core_cycles_prev; update_freq_counters_refs(); - const_cnt = this_cpu_read(arch_const_cycles_prev); - core_cnt = this_cpu_read(arch_core_cycles_prev); + const_cnt = amu_sample->arch_const_cycles_prev; + core_cnt = amu_sample->arch_core_cycles_prev; + /* + * This should not happen unless the AMUs have been reset and the + * counter values have not been restored - unlikely + */ if (unlikely(core_cnt <= prev_core_cnt || const_cnt <= prev_const_cnt)) return; @@ -182,6 +198,8 @@ static void amu_scale_freq_tick(void) scale = min_t(unsigned long, scale, SCHED_CAPACITY_SCALE); this_cpu_write(arch_freq_scale, (unsigned long)scale); + + amu_sample->last_scale_update = jiffies; } static struct scale_freq_data amu_sfd = { @@ -189,6 +207,80 @@ static struct scale_freq_data amu_sfd = { .set_freq_scale = amu_scale_freq_tick, }; +static __always_inline bool amu_fie_cpu_supported(unsigned int cpu) +{ + return cpumask_available(amu_fie_cpus) && + cpumask_test_cpu(cpu, amu_fie_cpus); +} + +#define AMU_SAMPLE_EXP_MS 20 + +int arch_freq_get_on_cpu(int cpu) +{ + struct amu_cntr_sample *amu_sample; + unsigned int start_cpu = cpu; + unsigned long last_update; + unsigned int freq = 0; + u64 scale; + + if (!amu_fie_cpu_supported(cpu) || !arch_scale_freq_ref(cpu)) + return -EOPNOTSUPP; + + while (1) { + + amu_sample = per_cpu_ptr(&cpu_amu_samples, cpu); + + last_update = amu_sample->last_scale_update; + + /* + * For those CPUs that are in full dynticks mode, or those that have + * not seen tick for a while, try an alternative source for the counters + * (and thus freq scale), if available, for given policy: this boils + * down to identifying an active cpu within the same freq domain, if any. + */ + if (!housekeeping_cpu(cpu, HK_TYPE_TICK) || + time_is_before_jiffies(last_update + msecs_to_jiffies(AMU_SAMPLE_EXP_MS))) { + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + int ref_cpu = cpu; + + if (!policy) + return -EINVAL; + + if (!cpumask_intersects(policy->related_cpus, + housekeeping_cpumask(HK_TYPE_TICK))) { + cpufreq_cpu_put(policy); + return -EOPNOTSUPP; + } + + + do { + ref_cpu = cpumask_next_wrap(ref_cpu, policy->cpus, + start_cpu, false); + + } while (ref_cpu < nr_cpu_ids && idle_cpu(ref_cpu)); + + cpufreq_cpu_put(policy); + + if (ref_cpu >= nr_cpu_ids) + /* No alternative to pull info from */ + return -EAGAIN; + + cpu = ref_cpu; + } else { + break; + } + } + /* + * Reversed computation to the one used to determine + * the arch_freq_scale value + * (see amu_scale_freq_tick for details) + */ + scale = arch_scale_freq_capacity(cpu); + freq = scale * arch_scale_freq_ref(cpu); + freq >>= SCHED_CAPACITY_SHIFT; + return freq; +} + static void amu_fie_setup(const struct cpumask *cpus) { int cpu; From patchwork Fri Jan 31 16:24:39 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Beata Michalska X-Patchwork-Id: 13955554 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4DB1DC0218F for ; Fri, 31 Jan 2025 16:31:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=aq4eaUxs6VzHkR8cIYvqvwq0cFMPu8jWCwRKgpRs7BE=; b=Slsw5GCtxAjphIBFlLnT3cikEF jAQsKv6hsWHU6zFDUZ0ct0IbbKwlv3w23sfSr7q95K88spg0/uxeqehpOfQNNYlmPAMqnRfZ3JSRy QnJKnGmBFreSd1cGSgIAgJd57qGFln61EYnhq9CmfC+54H3CG9ve0X0/ToBaKPWNfM9EC0mrCtrU3 yuEOsyu3oRBB/d8L1hjoWz9/L0gBLelDXupJoZkVg9jrTsgHW+3mDL6VEf3an0QN7lTcx+TvMYd1D c6UYZKMoK6MGXWpoUIu3GSN5yfRMb/9NZLYIOGgM5A9oH0bNEKc4u6S0cn6hvMnOmjius8CELD8qJ SiXa/F6g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tdtvf-0000000Az8y-06zF; Fri, 31 Jan 2025 16:31:39 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tdtpN-0000000Ay6F-3W5B for linux-arm-kernel@lists.infradead.org; Fri, 31 Jan 2025 16:25:11 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C221DFEC; Fri, 31 Jan 2025 08:25:34 -0800 (PST) Received: from e125905.cambridge.arm.com (e125905.cambridge.arm.com [10.1.194.73]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 4656F3F694; Fri, 31 Jan 2025 08:25:07 -0800 (PST) From: Beata Michalska To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, ionela.voinescu@arm.com, sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, rafael@kernel.org, viresh.kumar@linaro.org Cc: sumitg@nvidia.com, yang@os.amperecomputing.com, vanshikonda@os.amperecomputing.com, lihuisong@huawei.com, zhanjie9@hisilicon.com, ptsm@linux.microsoft.com Subject: [PATCH v10 4/4] arm64: Update AMU-based freq scale factor on entering idle Date: Fri, 31 Jan 2025 16:24:39 +0000 Message-Id: <20250131162439.3843071-5-beata.michalska@arm.com> In-Reply-To: <20250131162439.3843071-1-beata.michalska@arm.com> References: <20250131162439.3843071-1-beata.michalska@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250131_082509_915372_ABC58B70 X-CRM114-Status: UNSURE ( 9.48 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Now that the frequency scale factor has been activated for retrieving current frequency on a given CPU, trigger its update upon entering idle. This will, to an extent, allow querying last known frequency in a non-invasive way. It will also improve the frequency scale factor accuracy when a CPU entering idle did not receive a tick for a while. As a consequence, for idle cores, the reported frequency will be the last one observed before entering the idle state. Suggested-by: Vanshidhar Konda Signed-off-by: Beata Michalska Reviewed-by: Prasanna Kumar T S M Reviewed-by: Sumit Gupta --- arch/arm64/kernel/topology.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index bd238e5c2133..6f0cab8e746b 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -213,6 +213,19 @@ static __always_inline bool amu_fie_cpu_supported(unsigned int cpu) cpumask_test_cpu(cpu, amu_fie_cpus); } +void arch_cpu_idle_enter(void) +{ + unsigned int cpu = smp_processor_id(); + + if (!amu_fie_cpu_supported(cpu)) + return; + + /* Kick in AMU update but only if one has not happened already */ + if (housekeeping_cpu(cpu, HK_TYPE_TICK) && + time_is_before_jiffies(per_cpu(cpu_amu_samples.last_scale_update, cpu))) + amu_scale_freq_tick(); +} + #define AMU_SAMPLE_EXP_MS 20 int arch_freq_get_on_cpu(int cpu)