[PATCH V2 0/8] perf: Expand perf_branch_entry

Anshuman Khandual anshuman.khandual at arm.com
Tue Mar 8 19:36:34 PST 2022


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@arm.com/
- https://lore.kernel.org/all/1643348653-24367-1-git-send-email-anshuman.khandual@arm.com/
- https://lore.kernel.org/all/1645681014-3346-1-git-send-email-anshuman.khandual@arm.com/

This series applies on v5.17-rc7

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@arm.com/

Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Ingo Molnar <mingo at redhat.com>
Cc: Arnaldo Carvalho de Melo <acme at kernel.org>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Alexander Shishkin <alexander.shishkin at linux.intel.com>
Cc: Jiri Olsa <jolsa at redhat.com>
Cc: Namhyung Kim <namhyung at kernel.org>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Will Deacon <will at kernel.org>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-perf-users at vger.kernel.org
Cc: linux-kernel at vger.kernel.org

Anshuman Khandual (8):
  perf: Add irq and exception return branch types
  perf: Add system error and not in transaction branch types
  perf: Extend branch type classification
  perf: Capture branch privilege information
  perf/tools: Add irq and exception return branch types
  perf/tools: Add system error and not in transaction branch types
  perf/tools: Extend branch type classification
  perf/tools: Add branch privilege information request flag

 arch/x86/events/intel/lbr.c              |  6 ++---
 include/uapi/linux/perf_event.h          | 31 +++++++++++++++++++++++-
 tools/include/uapi/linux/perf_event.h    | 31 +++++++++++++++++++++++-
 tools/perf/Documentation/perf-record.txt |  1 +
 tools/perf/util/branch.c                 |  7 +++++-
 tools/perf/util/parse-branch-options.c   |  1 +
 6 files changed, 71 insertions(+), 6 deletions(-)

-- 
2.25.1




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