From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 27D0EC433ED for ; Fri, 14 May 2021 16:17:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E54C4613F1 for ; Fri, 14 May 2021 16:17:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233188AbhENQSM (ORCPT ); Fri, 14 May 2021 12:18:12 -0400 Received: from foss.arm.com ([217.140.110.172]:52036 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229958AbhENQSK (ORCPT ); Fri, 14 May 2021 12:18:10 -0400 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 7AC651713; Fri, 14 May 2021 09:16:58 -0700 (PDT) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4AB033F73B; Fri, 14 May 2021 09:16:56 -0700 (PDT) Subject: Re: [PATCH 2/3] arch_topology: obtain cpu capacity using information from CPPC To: Ionela Voinescu , Sudeep Holla , "Rafael J . Wysocki" , Thomas Gleixner , Ingo Molnar , Giovanni Gherdovich , Catalin Marinas , Will Deacon , Valentin Schneider Cc: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20210514095339.12979-1-ionela.voinescu@arm.com> <20210514095339.12979-3-ionela.voinescu@arm.com> From: Dietmar Eggemann Message-ID: <3c3f6d32-3560-2c54-beae-36f53d2572e7@arm.com> Date: Fri, 14 May 2021 18:16:50 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210514095339.12979-3-ionela.voinescu@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/05/2021 11:53, Ionela Voinescu wrote: [...] > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > index c1179edc0f3b..f710d64f125b 100644 > --- a/drivers/base/arch_topology.c > +++ b/drivers/base/arch_topology.c > @@ -291,6 +291,45 @@ bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu) > return !ret; > } > > +#ifdef CONFIG_ACPI_CPPC_LIB > +#include init_cpu_capacity_cppc() shares a lot of functionality with the existing DT/CPUfreq-based approach (topology_parse_cpu_capacity(), register_cpufreq_notifier(), init_cpu_capacity_callback()). It looks like that the different ways of invocation (two steps per cpu vs. one step for all cpus) makes it hard to restructure the code to create more common bits. > +void init_cpu_capacity_cppc(void) > +{ > + struct cppc_perf_caps perf_caps; > + int cpu; > + > + if (likely(acpi_disabled || !acpi_cpc_valid())) likely(acpi_disabled) ? > + return; > + > + raw_capacity = kcalloc(num_possible_cpus(), sizeof(*raw_capacity), > + GFP_KERNEL); > + if (!raw_capacity) > + return; > + > + for_each_possible_cpu(cpu) { > + if (!cppc_get_perf_caps(cpu, &perf_caps)) { > + raw_capacity[cpu] = perf_caps.highest_perf; > + pr_debug("%s: CPU%d cpu_capacity=%u (raw).\n", > + __func__, cpu, raw_capacity[cpu]); There is quite a variety in the layout of the pr_xxx() log messages in this file. Originally the 'cpu_capacity:' was used to indicate that this log is from drivers/base/arch_topology.c. Now the GCC __func__ identifier is used. Maybe this can be aligned better? Especially since the functionality used in the existing DT-driven and now in the new CPPC-driven functionality is quite similar. Debugging is so much easier with consistent log strings. > + } else { > + pr_err("%s: CPU%d missing highest performance.\n", > + __func__, cpu); > + pr_err("%s: fallback to 1024 for all CPUs\n", > + __func__); > + goto exit; > + } > + } > + > + topology_normalize_cpu_scale(); > + schedule_work(&update_topology_flags_work); > + pr_debug("%s: cpu_capacity initialization done\n", __func__); > + > +exit: > + free_raw_capacity(); > +} > +#endif In case a system has CONFIG_ACPI_CPPC_LIB what does this mean for the DT-based approach via `register_cpufreq_notifier()`? Looks like we rely on: 376 static int __init register_cpufreq_notifier(void) ... 385 if (!acpi_disabled || ...) 386 return -EINVAL; to disable the CPUfreq part of the DT/CPUfreq-based approach on an ACPI system. [...]