Re: [PATCH V5 0/8] perf: Expand perf_branch_entry

From: Anshuman Khandual
Date: Mon Apr 11 2022 - 01:45:42 EST




On 4/4/22 10:20, Anshuman Khandual wrote:
> Branch Record Buffer Extension (BRBE) implementation on arm64 captures more
> branch type classification which cannot be accommodated in the current perf
> branch record format via perf_branch_entry.type element (4 bit field). Also
> it captures privilege information which does not have a corresponding slot
> in perf_branch_entry. This series expands struct perf_branch_entry, to meet
> both these requirements without breaking the existing user space ABI for
> perf tools.
>
> All architecture specific branch types added via perf_branch_entry.new_type
> field in [PATCH 3/4] will be used in BRBE implementation on arm64 platform
> later on with the following map.
>
> #ifdef CONFIG_ARM64
> #define PERF_BR_FIQ PERF_BR_NEW_ARCH_1
> #define PERF_BR_DEBUG_HALT PERF_BR_NEW_ARCH_2
> #define PERF_BR_DEBUG_EXIT PERF_BR_NEW_ARCH_3
> #define PERF_BR_DEBUG_INST PERF_BR_NEW_ARCH_4
> #define PERF_BR_DEBUG_DATA PERF_BR_NEW_ARCH_5
> #endif
>
> This actually combines following patches and series into a single series.
>
> - https://lore.kernel.org/all/1642998653-21377-12-git-send-email-anshuman.khandual@xxxxxxx/
> - https://lore.kernel.org/all/1643348653-24367-1-git-send-email-anshuman.khandual@xxxxxxx/
> - https://lore.kernel.org/all/1645681014-3346-1-git-send-email-anshuman.khandual@xxxxxxx/
>
> This series applies on v5.18-rc1
>
> perf API
>
> The series being applied
>
> - Clean : tools/perf/check-headers.sh
> - Clean : diff -u tools/include/uapi/linux/perf_event.h include/uapi/linux/perf_event.h
>
> Todo
>
> - Update perf report tool to process PERF_BR_EXTEND_ABI (when available),
> then fetch and report branch types from perf_branch_entry.new_type field.
>
> References
>
> - BRBE captured branch record information
>
> https://developer.arm.com/documentation/ddi0601/2021-12/AArch64-Registers/BRBINF-n--EL1--Branch-Record-Buffer-Information-Register--n-?lang=en
>
> - BRBE based perf branch stack implementation on arm64 platform
>
> https://lore.kernel.org/all/1642998653-21377-1-git-send-email-anshuman.khandual@xxxxxxx/
>
> Changes in V5:
>
> - Dropped patches [PATCH 1/10] and [PATCH 6/10] related to PERF_BR_[RET|IRQ] - merged
> via the commit cedd3614e5d9c809 ("perf: Add irq and exception return branch types")
>
> - Rebased series on v5.18-rc1

Gentle ping, any updates on this series ?