From patchwork Wed Oct 25 09:38:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zeng Heng X-Patchwork-Id: 738609 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 458FEC0032E for ; Wed, 25 Oct 2023 09:33:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234415AbjJYJdr (ORCPT ); Wed, 25 Oct 2023 05:33:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232808AbjJYJdp (ORCPT ); Wed, 25 Oct 2023 05:33:45 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37311CE; Wed, 25 Oct 2023 02:33:43 -0700 (PDT) Received: from kwepemi500024.china.huawei.com (unknown [172.30.72.56]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4SFkF46rL7z15NKS; Wed, 25 Oct 2023 17:30:48 +0800 (CST) Received: from huawei.com (10.175.103.91) by kwepemi500024.china.huawei.com (7.221.188.100) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Wed, 25 Oct 2023 17:33:39 +0800 From: Zeng Heng To: , , , , , , , , , , , CC: , , , , Subject: [PATCH 2/3] cpufreq: CPPC: Keep the target core awake when reading its cpufreq rate Date: Wed, 25 Oct 2023 17:38:46 +0800 Message-ID: <20231025093847.3740104-3-zengheng4@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231025093847.3740104-1-zengheng4@huawei.com> References: <20231025093847.3740104-1-zengheng4@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.103.91] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemi500024.china.huawei.com (7.221.188.100) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org As ARM AMU's document says, all counters are subject to any changes in clock frequency, including clock stopping caused by the WFI and WFE instructions. Therefore, using smp_call_on_cpu() to trigger target CPU to read self's AMU counters, which ensures the counters are working properly while cstate feature is enabled. Reported-by: Sumit Gupta Link: https://lore.kernel.org/all/20230418113459.12860-7-sumitg@nvidia.com/ Signed-off-by: Zeng Heng --- drivers/cpufreq/cppc_cpufreq.c | 39 ++++++++++++++++++++++++++-------- 1 file changed, 30 insertions(+), 9 deletions(-) diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index fe08ca419b3d..321a9dc9484d 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -90,6 +90,12 @@ static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data, struct cppc_perf_fb_ctrs *fb_ctrs_t0, struct cppc_perf_fb_ctrs *fb_ctrs_t1); +struct fb_ctr_pair { + u32 cpu; + struct cppc_perf_fb_ctrs fb_ctrs_t0; + struct cppc_perf_fb_ctrs fb_ctrs_t1; +}; + /** * cppc_scale_freq_workfn - CPPC arch_freq_scale updater for frequency invariance * @work: The work item. @@ -840,9 +846,24 @@ static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data, return (reference_perf * delta_delivered) / delta_reference; } +static int cppc_get_perf_ctrs_pair(void *val) +{ + struct fb_ctr_pair *fb_ctrs = val; + int cpu = fb_ctrs->cpu; + int ret; + + ret = cppc_get_perf_ctrs(cpu, &fb_ctrs->fb_ctrs_t0); + if (ret) + return ret; + + udelay(2); /* 2usec delay between sampling */ + + return cppc_get_perf_ctrs(cpu, &fb_ctrs->fb_ctrs_t1); +} + static unsigned int cppc_cpufreq_get_rate(unsigned int cpu) { - struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0}; + struct fb_ctr_pair fb_ctrs = { .cpu = cpu, }; struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); struct cppc_cpudata *cpu_data = policy->driver_data; u64 delivered_perf; @@ -850,18 +871,18 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu) cpufreq_cpu_put(policy); - ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t0); - if (ret) - return 0; - - udelay(2); /* 2usec delay between sampling */ + if (cpu_has_amu_feat(cpu)) + ret = smp_call_on_cpu(cpu, cppc_get_perf_ctrs_pair, + &fb_ctrs, false); + else + ret = cppc_get_perf_ctrs_pair(&fb_ctrs); - ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t1); if (ret) return 0; - delivered_perf = cppc_perf_from_fbctrs(cpu_data, &fb_ctrs_t0, - &fb_ctrs_t1); + delivered_perf = cppc_perf_from_fbctrs(cpu_data, + &fb_ctrs.fb_ctrs_t0, + &fb_ctrs.fb_ctrs_t1); return cppc_cpufreq_perf_to_khz(cpu_data, delivered_perf); }