Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <1803209.Mvru99baaF@kreacher> <X/25ssA2scFSu+3/@hirez.programming.kicks-ass.net>
 <CAJZ5v0gHHPcBbL-EnCYJieMV-pRJWsjb5qC-iqHYznYjzrkitw@mail.gmail.com>
In-Reply-To: <CAJZ5v0gHHPcBbL-EnCYJieMV-pRJWsjb5qC-iqHYznYjzrkitw@mail.gmail.com>
From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Tue, 19 Jan 2021 16:12:20 +0100
Message-ID: <CAJZ5v0gY+WjB2q=wnRYxpwFmLzOcLMKewrCgKdpC0oNPFgoDww@mail.gmail.com>
Subject: Re: [PATCH] x86: PM: Register syscore_ops for scale invariance
To:     "Rafael J. Wysocki" <rafael@kernel.org>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Linux PM <linux-pm@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        x86 Maintainers <x86@kernel.org>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Giovanni Gherdovich <ggherdovich@suse.com>,
        Giovanni Gherdovich <ggherdovich@suse.cz>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, Jan 12, 2021 at 4:10 PM Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> On Tue, Jan 12, 2021 at 4:02 PM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Fri, Jan 08, 2021 at 07:05:59PM +0100, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > >
> > > On x86 scale invariace tends to be disabled during resume from
> > > suspend-to-RAM, because the MPERF or APERF MSR values are not as
> > > expected then due to updates taking place after the platform
> > > firmware has been invoked to complete the suspend transition.
> > >
> > > That, of course, is not desirable, especially if the schedutil
> > > scaling governor is in use, because the lack of scale invariance
> > > causes it to be less reliable.
> > >
> > > To counter that effect, modify init_freq_invariance() to register
> > > a syscore_ops object for scale invariance with the ->resume callback
> > > pointing to init_counter_refs() which will run on the CPU starting
> > > the resume transition (the other CPUs will be taken care of the
> > > "online" operations taking place later).
> > >
> > > Fixes: e2b0d619b400 ("x86, sched: check for counters overflow in frequency invariant accounting")
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > Thanks!, I'll take it through the sched/urgent tree?
>
> That works, thanks!

Any news on this front?  It's been a few days ...