From: Andi Kleen <ak@linux.intel.com>
To: "Mi, Dapeng" <dapeng1.mi@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Kan Liang <kan.liang@linux.intel.com>,
Eranian Stephane <eranian@google.com>,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Dapeng Mi <dapeng1.mi@intel.com>,
kernel test robot <oliver.sang@intel.com>
Subject: Re: [Patch v3 3/7] perf/x86: Check if cpuc->events[*] pointer exists before accessing it
Date: Wed, 20 Aug 2025 18:51:30 -0700 [thread overview]
Message-ID: <aKZ7omM0-3i72hfr@tassilo> (raw)
In-Reply-To: <fab2a035-5ab3-4e24-bd3e-760a4b9be5e8@linux.intel.com>
On Wed, Aug 20, 2025 at 01:54:17PM +0800, Mi, Dapeng wrote:
>
> On 8/20/2025 1:44 PM, Andi Kleen wrote:
> >> Andi, I didn't fully get the exact meaning about the "log" here. When
> >> throttle is triggered, perf_event_throttle() has already called
> >> perf_log_throttle() to log the throttle event although only for the group
> >> leader. Is it enough?
> > Throttle normally doesn't involve data loss, just less samples. But this
> > is data loss, so it's an overflow.
>
> IIUC, there should be no data loss, the unprocessed PEBS records of these
> throttled events would be still processed eventually by calling
> intel_pmu_drain_pebs_buffer() when stopping the event.
Makes sense. Thanks,
-Andi
next prev parent reply other threads:[~2025-08-21 1:51 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-20 2:30 [Patch v3 0/7] x86 perf bug fixes and optimization Dapeng Mi
2025-08-20 2:30 ` [Patch v3 1/7] perf/x86/intel: Use early_initcall() to hook bts_init() Dapeng Mi
2025-08-20 2:30 ` [Patch v3 2/7] perf/x86/intel: Fix IA32_PMC_x_CFG_B MSRs access error Dapeng Mi
2025-08-20 2:30 ` [Patch v3 3/7] perf/x86: Check if cpuc->events[*] pointer exists before accessing it Dapeng Mi
2025-08-20 3:41 ` Andi Kleen
2025-08-20 5:33 ` Mi, Dapeng
2025-08-20 5:44 ` Andi Kleen
2025-08-20 5:54 ` Mi, Dapeng
2025-08-21 1:51 ` Andi Kleen [this message]
2025-08-21 13:35 ` Peter Zijlstra
2025-08-22 5:26 ` Mi, Dapeng
2025-08-26 3:47 ` Mi, Dapeng
2025-08-20 2:30 ` [Patch v3 4/7] perf/x86: Add PERF_CAP_PEBS_TIMING_INFO flag Dapeng Mi
2025-08-20 2:30 ` [Patch v3 5/7] perf/x86/intel: Change macro GLOBAL_CTRL_EN_PERF_METRICS to BIT_ULL(48) Dapeng Mi
2025-08-20 2:30 ` [Patch v3 6/7] perf/x86/intel: Add ICL_FIXED_0_ADAPTIVE bit into INTEL_FIXED_BITS_MASK Dapeng Mi
2025-08-20 2:30 ` [Patch v3 7/7] perf/x86: Print PMU counters bitmap in x86_pmu_show_pmu_cap() Dapeng Mi
2025-08-20 15:55 ` [Patch v3 0/7] x86 perf bug fixes and optimization Liang, Kan
2025-08-21 13:39 ` Peter Zijlstra
2025-08-22 5:29 ` Mi, Dapeng
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