From: Andi Kleen <ak@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>,
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, eranian@google.com,
alexey.v.bayduraev@linux.intel.com, tinghao.zhang@intel.com,
Sandipan Das <sandipan.das@amd.com>,
Ravi Bangoria <ravi.bangoria@amd.com>,
Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Subject: Re: [RESEND PATCH V3 1/6] perf: Add branch stack extra
Date: Tue, 3 Oct 2023 08:06:59 -0700 [thread overview]
Message-ID: <ZRwuE8LPkwtkjX5C@tassilo> (raw)
In-Reply-To: <20231003102733.GC1539@noisy.programming.kicks-ass.net>
> I'm thinking we should do something like expose branch_counter_nr and
> branch_counter_width in the sysfs node, and then rename this extra field
> to counters.
>
> Then userspace can do something like:
>
> for (i = 0; i < branch_counter_nr; i++) {
> counter[i] = counters & ((1 << branch_counter_width) - 1);
> counters >>= branch_counter_width;
> }
>
> to extract the actual counter values.
perf script/report won't necessarily have access to the sysfs
values if they run on a different system
It would need extra PT style metadata written by perf record to
perf.data and read by the user tools.
Seems complicated. It would be better if it just parsed on its own.
-Andi
next prev parent reply other threads:[~2023-10-03 15:09 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-11 15:48 [RESEND PATCH V3 1/6] perf: Add branch stack extra kan.liang
2023-09-11 15:48 ` [RESEND PATCH V3 2/6] perf/x86: Add PERF_X86_EVENT_NEEDS_BRANCH_STACK flag kan.liang
2023-09-11 15:48 ` [RESEND PATCH V3 3/6] perf: Add branch_sample_call_stack kan.liang
2023-09-11 15:48 ` [RESEND PATCH V3 4/6] perf/x86/intel: Support LBR event logging kan.liang
2023-09-11 15:48 ` [RESEND PATCH V3 5/6] tools headers UAPI: Sync include/uapi/linux/perf_event.h header with the kernel kan.liang
2023-09-11 15:48 ` [RESEND PATCH V3 6/6] perf tools: Add branch event knob kan.liang
2023-10-02 13:49 ` [RESEND PATCH V3 1/6] perf: Add branch stack extra Liang, Kan
2023-10-02 15:45 ` Peter Zijlstra
2023-10-02 19:19 ` Liang, Kan
2023-10-02 21:37 ` Peter Zijlstra
2023-10-03 0:57 ` Liang, Kan
2023-10-03 10:27 ` Peter Zijlstra
2023-10-03 12:57 ` Liang, Kan
2023-10-03 15:06 ` Andi Kleen [this message]
2023-10-03 15:58 ` Liang, Kan
2023-10-03 16:33 ` Peter Zijlstra
2023-10-03 16:55 ` Andi Kleen
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