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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9DB6C4167D for ; Thu, 2 Nov 2023 10:31:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346654AbjKBKbI (ORCPT ); Thu, 2 Nov 2023 06:31:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346112AbjKBKbH (ORCPT ); Thu, 2 Nov 2023 06:31:07 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 43373112; Thu, 2 Nov 2023 03:31:04 -0700 (PDT) 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 1803B2F4; Thu, 2 Nov 2023 03:31:46 -0700 (PDT) Received: from e129154.nice.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8044E3F67D; Thu, 2 Nov 2023 03:30:56 -0700 (PDT) Date: Thu, 2 Nov 2023 11:30:03 +0100 From: Beata Michalska To: Vincent Guittot Cc: linux@armlinux.org.uk, catalin.marinas@arm.com, will@kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, sudeep.holla@arm.com, gregkh@linuxfoundation.org, rafael@kernel.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, viresh.kumar@linaro.org, lenb@kernel.org, robert.moore@intel.com, lukasz.luba@arm.com, ionela.voinescu@arm.com, pierre.gondois@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org, acpica-devel@lists.linuxfoundation.org, conor.dooley@microchip.com, suagrfillet@gmail.com, ajones@ventanamicro.com, lftan@kernel.org Subject: Re: [PATCH v4 7/7] arm64/amu: use capacity_ref_freq to set AMU ratio Message-ID: References: <20231027080400.56703-1-vincent.guittot@linaro.org> <20231027080400.56703-8-vincent.guittot@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi Vincent, On Wed, Nov 01, 2023 at 10:04:27AM +0100, Vincent Guittot wrote: > Hi Beata, > > On Wed, 1 Nov 2023 at 00:59, Beata Michalska wrote: > > > > On Fri, Oct 27, 2023 at 10:04:00AM +0200, Vincent Guittot wrote: > > > Use the new capacity_ref_freq to set the ratio that is used by AMU for > > > computing the arch_scale_freq_capacity(). > > > This helps to keep everything aligned using the same reference for > > > computing CPUs capacity. > > > > > [..] > > > > @@ -381,6 +385,9 @@ void topology_init_cpu_capacity_cppc(void) > > > } > > > > > > for_each_possible_cpu(cpu) { > > > + freq_inv_set_max_ratio(cpu, > > > + per_cpu(capacity_ref_freq, cpu) * HZ_PER_KHZ); > > > + > > The capacity_ref_freq set earlier will still lead to units mismatch, > > as at the point of calling topology_init_cpu_capacity_cppc the lowest & nominal > > frequencies will be provided in MHz (unless I have missed smth). > > I don't get your point: > the unit of per_cpu(capacity_freq_ref, cpu) is Khz > > For cppc, we have > per_cpu(capacity_freq_ref, cpu) = cppc_perf_to_khz(&perf_caps, > raw_capacity[cpu]); > > freq_inv_set_max_ratio() uses > arch_timer_get_rate() which returns a freq in Hz > and > per_cpu(capacity_freq_ref, cpu) * HZ_PER_KHZ. to get a freq in Hz too. > Apologies, I should have been more verbose here. Before the change made in [1] the cppc_perf_to_khz was indeed operating on lowest & nominal frequency values expressed in kHZ, as those were appropriately amended: cppc_cpufreq_cpu_init |__> cppc_cpufreq_get_cpu_data: |__> ... /* Convert the lowest and nominal freq from MHz to KHz */ cpu_data->perf_caps.lowest_freq *= 1000; cpu_data->perf_caps.nominal_freq *= 1000; So far cppc_perf_to_khz (previously cppc_cpufreq_perf_to_khz) was being called with the post-processed CPC data (through cppc_cpufreq_get_cpu_data) and thus guaranteed to be operating on values in kHz. With the new changes the cppc_perf_to_khz will operate on raw CPC data, which are expressed in MHz.(as per acpi spec) --- Best Regards B. > > This means that use of both, the capacity_ref_freq and the arch_freq_scale > > will generate unexpected results, so I guess this should get amended in the > > preceding patch (?) [1] > > > > --- > > BR > > B. > > > > [1] https://lore.kernel.org/linux-arm-kernel/20231027080400.56703-4-vincent.guittot@linaro.org/T/#m42daa167097edc190b1cfc05382c385ed801d909 > > > > > capacity = raw_capacity[cpu]; > > > capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT, > > > capacity_scale); > > > @@ -422,8 +429,11 @@ init_cpu_capacity_callback(struct notifier_block *nb, > > > > > > cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus); > > > > > > - for_each_cpu(cpu, policy->related_cpus) > > > + for_each_cpu(cpu, policy->related_cpus) { > > > per_cpu(capacity_ref_freq, cpu) = policy->cpuinfo.max_freq; > > > + freq_inv_set_max_ratio(cpu, > > > + per_cpu(capacity_ref_freq, cpu) * HZ_PER_KHZ); > > > + } > > > > > > if (cpumask_empty(cpus_to_visit)) { > > > topology_normalize_cpu_scale(); > > > diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h > > > index 38ca6c76af56..ffdf0b7c55fa 100644 > > > --- a/include/linux/arch_topology.h > > > +++ b/include/linux/arch_topology.h > > > @@ -99,6 +99,7 @@ void update_siblings_masks(unsigned int cpu); > > > void remove_cpu_topology(unsigned int cpuid); > > > void reset_cpu_topology(void); > > > int parse_acpi_topology(void); > > > +void freq_inv_set_max_ratio(int cpu, u64 max_rate); > > > #endif > > > > > > #endif /* _LINUX_ARCH_TOPOLOGY_H_ */ > > > -- > > > 2.34.1 > > >