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From: "Liang, Kan" <kan.liang@linux.intel.com>
To: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [perf] unchecked MSR access error: WRMSR to 0x3f1
Date: Thu, 19 Jun 2025 12:06:21 -0400	[thread overview]
Message-ID: <9aee2b65-e43a-4fcd-a929-a98269621315@linux.intel.com> (raw)
In-Reply-To: <52656281-ab73-baf7-0a80-ebcbe79dfca2@maine.edu>



On 2025-06-19 11:17 a.m., Vince Weaver wrote:
> On Wed, 18 Jun 2025, Vince Weaver wrote:
> 
>> On Wed, 18 Jun 2025, Liang, Kan wrote:
>>
>>> No, the error message doesn't say it. Just want to check if you have
>>> extra information. Because the Topdown perf metrics is only supported on
>>> p-core. I want to understand whether the code messes up with e-core.
>>
>> I can't easily tell from the fuzzer as it intentionally switches cores 
>> often.  I guess I could patch the kernel to report CPU when the WRMSR 
>> error triggers.
> 
> I've patched the kernel to get rid of the warn_once() and added a printk
> for smp_processor_id()  (is that what I want to print?)  In any case that 
> reports the warning is happening on CPU1 which is actually a P core, not 
> an atom core.

Thanks for the confirmation.
I've tried fuzzer in some newer machines (later than raptor-lake), but I
haven't reproduce it yet. I will try to find a raptor-lake for more tests.

Thanks,
Kan


  reply	other threads:[~2025-06-19 16:06 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-17 15:39 [perf] unchecked MSR access error: WRMSR to 0x3f1 Vince Weaver
2025-06-17 15:50 ` Abhigyan ghosh
2025-06-17 19:47 ` Liang, Kan
2025-06-18  3:49   ` Vince Weaver
2025-06-18 11:02     ` Liang, Kan
2025-06-18 18:26       ` Vince Weaver
2025-06-19 15:17         ` Vince Weaver
2025-06-19 16:06           ` Liang, Kan [this message]
2025-06-19 20:10             ` Vince Weaver
2025-06-20 11:07               ` Liang, Kan
2025-06-20 16:12                 ` Vince Weaver

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