From: Beata Michalska <beata.michalska@arm.com>
To: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, ionela.voinescu@arm.com,
vanshikonda@os.amperecomputing.com
Cc: sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com,
vincent.guittot@linaro.org, sumitg@nvidia.com,
yang@os.amperecomputing.com, lihuisong@huawei.com,
viresh.kumar@linaro.org
Subject: [PATCH v5 0/5] Add support for AArch64 AMUv1-based arch_freq_get_on_cpu
Date: Wed, 17 Apr 2024 10:38:43 +0100 [thread overview]
Message-ID: <20240417093848.1555462-1-beata.michalska@arm.com> (raw)
Introducing arm64 specific version of arch_freq_get_on_cpu, cashing on
existing implementation for FIE and AMUv1 support: the frequency scale
factor, updated on each sched tick, serves as a base for retrieving
the frequency for a given CPU, representing an average frequency
reported between the ticks - thus its accuracy is limited.
The changes have been rather lightly (due to some limitations) tested on
an FVP model. Note that some small discrepancies have been observed while
testing (on the model) and this is currently being investigated, though it
should not have any significant impact on the overall results.
Relevant discussions:
[1] https://lore.kernel.org/all/20240229162520.970986-1-vanshikonda@os.amperecomputing.com/
[2] https://lore.kernel.org/all/7eozim2xnepacnnkzxlbx34hib4otycnbn4dqymfziqou5lw5u@5xzpv3t7sxo3/
[3] https://lore.kernel.org/all/20231212072617.14756-1-lihuisong@huawei.com/
[4] https://lore.kernel.org/lkml/ZIHpd6unkOtYVEqP@e120325.cambridge.arm.com/T/#m4e74cb5a0aaa353c60fedc6cfb95ab7a6e381e3c
v5:
- Fix invalid access to cpumask
- Reworked finding reference cpu when getting the freq
v4:
- dropping seqcount
- fixing identifying active cpu within given policy
- skipping full dynticks cpus when retrieving the freq
- bringing back plugging in arch_freq_get_on_cpu into cpuinfo_cur_freq
v3:
- dropping changes to cpufreq_verify_current_freq
- pulling in changes from Ionela initializing capacity_freq_ref to 0
(thanks for that!) and applying suggestions made by her during last review:
- switching to arch_scale_freq_capacity and arch_scale_freq_ref when
reversing freq scale factor computation
- swapping shift with multiplication
- adding time limit for considering last scale update as valid
- updating frequency scale factor upon entering idle
v2:
- Splitting the patches
- Adding comment for full dyntick mode
- Plugging arch_freq_get_on_cpu into cpufreq_verify_current_freq instead
of in show_cpuinfo_cur_freq to allow the framework to stay more in sync
with potential freq changes
Beata Michalska (4):
arm64: amu: Rule out potential usa after free
arm64: Provide an AMU-based version of arch_freq_get_on_cpu
arm64: Update AMU-based frequency scale factor on entering idle
cpufreq: Use arch specific feedback for cpuinfo_cur_freq
Ionela Voinescu (1):
arch_topology: init capacity_freq_ref to 0
arch/arm64/kernel/topology.c | 129 ++++++++++++++++++++++++++++++++---
drivers/base/arch_topology.c | 8 ++-
drivers/cpufreq/cpufreq.c | 4 +-
3 files changed, 126 insertions(+), 15 deletions(-)
--
2.25.1
next reply other threads:[~2024-04-17 9:39 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-17 9:38 Beata Michalska [this message]
2024-04-17 9:38 ` [PATCH v5 1/5] arch_topology: init capacity_freq_ref to 0 Beata Michalska
2024-04-18 10:50 ` Sudeep Holla
2024-04-17 9:38 ` [PATCH v5 2/5] arm64: amu: Rule out potential use after free Beata Michalska
2024-04-18 10:50 ` Sudeep Holla
2024-04-18 15:55 ` Beata Michalska
2024-04-24 10:25 ` Sudeep Holla
2024-04-25 14:27 ` Beata Michalska
2024-05-07 7:24 ` Ionela Voinescu
2024-04-17 9:38 ` [PATCH v5 3/5] arm64: Provide an AMU-based version of arch_freq_get_on_cpu Beata Michalska
2024-04-18 1:39 ` Vanshidhar Konda
2024-04-26 10:50 ` Beata Michalska
2024-04-17 9:38 ` [PATCH v5 4/5] arm64: Update AMU-based frequency scale factor on entering idle Beata Michalska
2024-04-17 9:38 ` [PATCH v5 5/5] cpufreq: Use arch specific feedback for cpuinfo_cur_freq Beata Michalska
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