From: "Mi, Dapeng" <dapeng1.mi@linux.intel.com>
To: tanze <tanze@kylinos.cn>,
peterz@infradead.org, kan.liang@linux.intel.com
Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
x86@kernel.org
Subject: Re: [PATCH v3] perf/x86/zhaoxin: Fix instructions error by missing fixedctr member
Date: Tue, 30 Sep 2025 10:49:56 +0800 [thread overview]
Message-ID: <c962d1a5-b941-4361-839c-c34e621de5ee@linux.intel.com> (raw)
In-Reply-To: <20250620023757.1429898-1-tanze@kylinos.cn>
On 6/20/2025 10:37 AM, tanze wrote:
> Perf's instructions event tests on Zhaoxin CPUs may exhibit:
>
> $perf stat -e instructions,cycles ls -l
>
> ......
> Performance counter stats for 'ls -l':
>
> 0 instructions # 0.00 insn per cycle
> 9,488,278 cycles
>
> 0.004365407 seconds time elapsed
>
> 0.003303000 seconds user
> 0.001099000 seconds sys
>
> The absence of the fixedctr member leads to an incorrect hwc->event_base
> value on Zhaoxin CPUs, causing a discrepancy in the instruction count
> reported by perf stat. This commit resolves the instruction count issue
> by properly initializing the fixedctr member.
>
> Fixes: 149fd4712bcd ("perf/x86/intel: Support Perfmon MSRs aliasing")
> Signed-off-by: tanze <tanze@kylinos.cn>
> Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
> ---
> arch/x86/events/zhaoxin/core.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/events/zhaoxin/core.c b/arch/x86/events/zhaoxin/core.c
> index 4bdfcf091200..3fc3f9abece9 100644
> --- a/arch/x86/events/zhaoxin/core.c
> +++ b/arch/x86/events/zhaoxin/core.c
> @@ -467,6 +467,7 @@ static const struct x86_pmu zhaoxin_pmu __initconst = {
> .schedule_events = x86_schedule_events,
> .eventsel = MSR_ARCH_PERFMON_EVENTSEL0,
> .perfctr = MSR_ARCH_PERFMON_PERFCTR0,
> + .fixedctr = MSR_ARCH_PERFMON_FIXED_CTR0,
> .event_map = zhaoxin_pmu_event_map,
> .max_events = ARRAY_SIZE(zx_pmon_event_map),
> .apic = 1,
LGTM.
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
next prev parent reply other threads:[~2025-09-30 2:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-19 3:19 [PATCH] perf/x86/zhaoxin: Fix instructions error by missing fixedctr member tanze
2025-06-19 14:33 ` Liang, Kan
2025-06-20 1:51 ` [PATCH v2 v2] " tanze
2025-06-20 2:10 ` [PATCH 0/1] CANCELLED: [PATCH " tanze
2025-06-20 2:19 ` tanze
2025-06-20 2:37 ` [PATCH v3] " tanze
2025-09-30 2:49 ` Mi, Dapeng [this message]
2025-10-15 8:55 ` tanze
2025-09-28 9:44 ` [PATCH] " tanze
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