From: Peter Zijlstra <peterz@infradead.org>
To: kan.liang@linux.intel.com
Cc: mingo@redhat.com, acme@kernel.org, linux-kernel@vger.kernel.org,
mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
jolsa@kernel.org, namhyung@kernel.org, irogers@google.com,
adrian.hunter@intel.com, ak@linux.intel.com, eranian@google.com,
alexey.v.bayduraev@linux.intel.com, tinghao.zhang@intel.com
Subject: Re: [PATCH V4 4/7] perf/x86/intel: Support LBR event logging
Date: Thu, 19 Oct 2023 13:12:02 +0200 [thread overview]
Message-ID: <20231019111202.GJ36211@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20231004184044.3062788-4-kan.liang@linux.intel.com>
On Wed, Oct 04, 2023 at 11:40:41AM -0700, kan.liang@linux.intel.com wrote:
> +static __always_inline void get_lbr_events(struct cpu_hw_events *cpuc,
> + int i, u64 info)
> +{
> + /*
> + * The later code will decide what content can be disclosed
> + * to the perf tool. It's no harmful to unconditionally update
> + * the cpuc->lbr_events.
> + * Pleae see intel_pmu_lbr_event_reorder()
> + */
> + cpuc->lbr_events[i] = info & LBR_INFO_EVENTS;
> +}
You could be forcing an extra cachemiss here. A long time ago I had
hacks to profile perf with perf, but perhaps PT can be abused for that
now?
next prev parent reply other threads:[~2023-10-19 11:12 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-04 18:40 [PATCH V4 1/7] perf: Add branch stack counters kan.liang
2023-10-04 18:40 ` [PATCH V4 2/7] perf/x86: Add PERF_X86_EVENT_NEEDS_BRANCH_STACK flag kan.liang
2023-10-04 18:40 ` [PATCH V4 3/7] perf: Add branch_sample_call_stack kan.liang
2023-10-04 18:40 ` [PATCH V4 4/7] perf/x86/intel: Support LBR event logging kan.liang
2023-10-19 9:23 ` Peter Zijlstra
2023-10-19 13:56 ` Liang, Kan
2023-10-19 9:26 ` Peter Zijlstra
2023-10-19 13:58 ` Liang, Kan
2023-10-19 10:52 ` Peter Zijlstra
2023-10-19 14:26 ` Liang, Kan
2023-10-19 18:18 ` Peter Zijlstra
2023-10-19 11:00 ` Peter Zijlstra
2023-10-19 14:28 ` Liang, Kan
2023-10-19 11:09 ` Peter Zijlstra
2023-10-19 14:31 ` Liang, Kan
2023-10-19 11:12 ` Peter Zijlstra [this message]
2023-10-20 12:45 ` Liang, Kan
2023-10-04 18:40 ` [PATCH V4 5/7] tools headers UAPI: Sync include/uapi/linux/perf_event.h header with the kernel kan.liang
2023-10-04 18:40 ` [PATCH V4 6/7] perf header: Support num and width of branch counters kan.liang
2023-10-04 18:40 ` [PATCH V4 7/7] perf tools: Add branch counter knob kan.liang
2023-10-16 17:48 ` [PATCH V4 1/7] perf: Add branch stack counters Liang, Kan
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