linux-kernel - Re: [PATCH v10 0/4] Add support for AArch64 AMUv1-based average freq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <Z7RQWgLksl4bBksr@arm.com>
Date: Tue, 18 Feb 2025 09:18:18 +0000
From: Catalin Marinas <catalin.marinas@....com>
To: Beata Michalska <beata.michalska@....com>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-pm@...r.kernel.org, ionela.voinescu@....com,
	sudeep.holla@....com, will@...nel.org, rafael@...nel.org,
	viresh.kumar@...aro.org, sumitg@...dia.com,
	yang@...amperecomputing.com, vanshikonda@...amperecomputing.com,
	lihuisong@...wei.com, zhanjie9@...ilicon.com,
	ptsm@...ux.microsoft.com, Jonathan Corbet <corbet@....net>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H . Peter Anvin" <hpa@...or.com>, Phil Auld <pauld@...hat.com>,
	x86@...nel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v10 0/4] Add support for AArch64 AMUv1-based average freq

On Tue, Feb 18, 2025 at 01:00:20AM +0100, Beata Michalska wrote:
> On Mon, Feb 17, 2025 at 09:32:06PM +0000, Catalin Marinas wrote:
> > On Fri, 31 Jan 2025 16:24:35 +0000, Beata Michalska wrote:
> > > This series adds support for obtaining an average CPU frequency based on
> > > a hardware provided feedback. The average frequency is being exposed via
> > > dedicated yet optional cpufreq sysfs attribute - cpuinfo_avg_freq.
> > > The architecture specific bits are being provided for AArch64, caching on
> > > existing implementation for FIE and AMUv1 support: the frequency scale
> > > factor, updated on each sched tick, serving as a base for retrieving
> > > the frequency for a given CPU, representing an average frequency
> > > reported between the ticks.
> > > 
> > > [...]
> >
> Thank you for that.
> 
> There is still a (not so) small issue with patch
> [3/4] arm64: Provide an AMU-based version of arch_freq_get_on_cpu.
> It did not come up while testing, sadly.
> No idea how I could have missed that, nor why I made the mistake
> in the first place.
> 
> The fix is pretty straightforward:
> 
> diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
> index 6f0cab8e746b..4bac26d8e29c 100644
> --- a/arch/arm64/kernel/topology.c
> +++ b/arch/arm64/kernel/topology.c
> @@ -268,7 +268,7 @@ int arch_freq_get_on_cpu(int cpu)
>  
>                         do {
>                                 ref_cpu = cpumask_next_wrap(ref_cpu, policy->cpus,
> -                                                           start_cpu, false);
> +                                                           start_cpu, true);
> 
> Please let me know if you want me to send new version with the fix applied.

Usually we apply another patch on top with a Fixes tag or just fold it
in if no-one relies on this branch being stable. I'll do the latter, no
need to resend.

Thanks.

-- 
Catalin