Re: [PATCH V7 4/6] arm64/perf: Add branch stack support in struct pmu_hw_events
From: Mark Rutland <mark.rutland@arm.com>
Date: 2023-01-12 14:00:41
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On Thu, Jan 05, 2023 at 08:40:37AM +0530, Anshuman Khandual wrote:
This adds branch records buffer pointer in 'struct pmu_hw_events' which can be used to capture branch records during PMU interrupt. This percpu pointer here needs to be allocated first before usage. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <redacted>
This looks fine, but it's difficult to review this without seeing how its lifetime is managed, and it feels like this should be folded into a subsequent patch which manages that. Thanks, Mark.
quoted hunk ↗ jump to hunk
--- include/linux/perf/arm_pmu.h | 9 +++++++++ 1 file changed, 9 insertions(+)diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 64e1b2594025..9184f9b33740 100644 --- a/include/linux/perf/arm_pmu.h +++ b/include/linux/perf/arm_pmu.h@@ -44,6 +44,13 @@ static_assert((PERF_EVENT_FLAG_ARCH & ARMPMU_EVT_47BIT) == ARMPMU_EVT_47BIT); }, \ } +#define MAX_BRANCH_RECORDS 64 + +struct branch_records { + struct perf_branch_stack branch_stack; + struct perf_branch_entry branch_entries[MAX_BRANCH_RECORDS]; +}; + /* The events for a given PMU register set. */ struct pmu_hw_events { /*@@ -70,6 +77,8 @@ struct pmu_hw_events { struct arm_pmu *percpu_pmu; int irq; + + struct branch_records *branches; }; enum armpmu_attr_groups {-- 2.25.1
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