Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) client-ip=23.128.96.33;
MIME-Version: 1.0
References: <20231208210855.407580-1-kan.liang@linux.intel.com>
 <ZXd7ZuxbNNsjAyqm@kernel.org> <07677ab2-c29b-499b-b473-f7535fb27a8c@linux.intel.com>
In-Reply-To: <07677ab2-c29b-499b-b473-f7535fb27a8c@linux.intel.com>
From:   Namhyung Kim <namhyung@kernel.org>
Date:   Tue, 12 Dec 2023 09:23:01 -0800
Message-ID: <CAM9d7ci-VVhubefMqkSQgK-B2e2z4QU1=TLJtC49wbWW=VNc8g@mail.gmail.com>
Subject: Re: [PATCH] perf top: Use evsel's cpus to replace user_requested_cpus
To:     "Liang, Kan" <kan.liang@linux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>, irogers@google.com,
        mark.rutland@arm.com, maz@kernel.org, marcan@marcan.st,
        linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8BIT
Precedence: bulk

On Tue, Dec 12, 2023 at 7:56 AM Liang, Kan <kan.liang@linux.intel.com> wrote:
>
>
>
> On 2023-12-11 4:13 p.m., Arnaldo Carvalho de Melo wrote:
> > Em Fri, Dec 08, 2023 at 01:08:55PM -0800, kan.liang@linux.intel.com escreveu:
> >> From: Kan Liang <kan.liang@linux.intel.com>
> >>
> >> perf top errors out on a hybrid machine
> >>  $perf top
> >>
> >>  Error:
> >>  The cycles:P event is not supported.
> >>
> >> The user_requested_cpus may contain CPUs that are invalid for a hybrid
> >> PMU. It causes perf_event_open to fail.
> >
> > ?
> >
> > All perf top expects is that the "cycles", the most basic one, be
> > collected, on all CPUs in the system.
> >
>
> Yes, but for hybrid there is no single "cycles" event which can cover
> all CPUs.

Does that mean the kernel would reject the legacy "cycles" event
on hybrid CPUs?

Thanks,
Namhyung