Re: [PATCH v2 00/16] perf arm64: Support data type profiling
From: Namhyung Kim
Date: Tue Apr 07 2026 - 02:32:07 EST
Hello,
On Fri, Apr 03, 2026 at 09:47:44AM +0000, Tengda Wu wrote:
> This patch series implements data type profiling support for arm64,
> building upon the foundational work previously contributed by Huafei [1].
> While the initial version laid the groundwork for arm64 data type analysis,
> this series iterates on that work by refining instruction parsing and
> extending support for core architectural features.
Thanks for working on this! I'm happy to see that the changes are well
organized and each commit explained the issues clearly.
>
> The series is organized as follows:
>
> 1. Fix disassembly mismatches (Patches 01-02)
> Current perf annotate supports three disassembly backends: llvm,
> capstone, and objdump. On arm64, inconsistencies between the output
> of these backends (specifically llvm/capstone vs. objdump) often
> prevent the tracker from correctly identifying registers and offsets.
> These patches resolve these mismatches, ensuring consistent instruction
> parsing across all supported backends.
>
> 2. Infrastructure for arm64 operand parsing (Patches 03-07)
> These patches establish the necessary infrastructure for arm64-specific
> operand handling. This includes implementing new callbacks and data
> structures to manage arm64's unique addressing modes and register sets.
> This foundation is essential for the subsequent type-tracking logic.
I've only checked up to this part so far. Let me write replies soon.
I'll continue to review later in this week.
>
> 3. Core instruction tracking (Patches 08-16)
> These patches implement the core logic for type tracking on arm64,
> covering a wide range of instructions including:
>
> * Memory Access: ldr/str variants (including stack-based access).
> * Arithmetic & Data Processing: mov, add, and adrp.
> * Special Access: System register access (mrs) and per-cpu variable
> tracking.
>
> The implementation draws inspiration from the existing x86 logic while
> adapting it to the nuances of the AArch64 ISA [2][3]. With these changes,
> perf annotate can successfully resolve memory locations and register
> types, enabling comprehensive data type profiling on arm64 platforms.
>
> Example Result
> ==============
>
> # perf mem record -a -K -- sleep 1
> # perf annotate --data-type --type-stat --stdio
> Annotate data type stats:
> total 6204, ok 5091 (82.1%), bad 1113 (17.9%)
I'm impressed that the success rate is quite high. But I think you need
to confirm that the findings are correct by taking a close look at each
result. You can try `perf annotate --code-with-type`.
Thanks,
Namhyung
> -----------------------------------------------------------
> 29 : no_sym
> 196 : no_var
> 806 : no_typeinfo
> 82 : bad_offset
> 1370 : insn_track
>
> Annotate type: 'struct page' in [kernel.kallsyms] (59208 samples):
> ============================================================================
> Percent offset size field
> 100.00 0 0x40 struct page {
> 9.95 0 0x8 long unsigned int flags;
> 52.83 0x8 0x28 union {
> 52.83 0x8 0x28 struct {
> 37.21 0x8 0x10 union {
> 37.21 0x8 0x10 struct list_head lru {
> 37.21 0x8 0x8 struct list_head* next;
> 0.00 0x10 0x8 struct list_head* prev;
> };
> 37.21 0x8 0x10 struct {
> 37.21 0x8 0x8 void* __filler;
> 0.00 0x10 0x4 unsigned int mlock_count;
> ...
>
> Changes since v1: (reworked from Huafei's series):
>
> - Fix inconsistencies in arm64 instruction output across llvm, capstone,
> and objdump disassembly backends.
> - Support arm64-specific addressing modes and operand formats. (Leo Yan)
> - Extend instruction tracking to support mov and add instructions,
> along with per-cpu and stack variables.
> - Include real-world examples in commit messages to demonstrate
> practical effects. (Namhyung Kim)
> - Improve type-tracking success rate (type stat) from 64.2% to 82.1%.
> https://lore.kernel.org/all/20250314162137.528204-1-lihuafei1@xxxxxxxxxx/
>
> Please let me know if you have any feedback.
>
> Thanks,
> Tengda
>
> [1] https://lore.kernel.org/all/20250314162137.528204-1-lihuafei1@xxxxxxxxxx/
> [2] https://developer.arm.com/documentation/102374/0103
> [3] https://github.com/flynd/asmsheets/releases/tag/v8
>
> ---
>
> Tengda Wu (16):
> perf llvm: Fix arm64 adrp instruction disassembly mismatch with
> objdump
> perf capstone: Fix arm64 jump/adrp disassembly mismatch with objdump
> perf annotate-arm64: Generalize arm64_mov__parse to support standard
> operands
> perf annotate-arm64: Handle load and store instructions
> perf annotate: Introduce extract_op_location callback for
> arch-specific parsing
> perf dwarf-regs: Adapt get_dwarf_regnum() for arm64
> perf annotate-arm64: Implement extract_op_location() callback
> perf annotate-arm64: Enable instruction tracking support
> perf annotate-arm64: Support load instruction tracking
> perf annotate-arm64: Support store instruction tracking
> perf annotate-arm64: Support stack variable tracking
> perf annotate-arm64: Support 'mov' instruction tracking
> perf annotate-arm64: Support 'add' instruction tracking
> perf annotate-arm64: Support 'adrp' instruction to track global
> variables
> perf annotate-arm64: Support per-cpu variable access tracking
> perf annotate-arm64: Support 'mrs' instruction to track 'current'
> pointer
>
> .../perf/util/annotate-arch/annotate-arm64.c | 642 +++++++++++++++++-
> .../util/annotate-arch/annotate-powerpc.c | 10 +
> tools/perf/util/annotate-arch/annotate-x86.c | 88 ++-
> tools/perf/util/annotate-data.c | 72 +-
> tools/perf/util/annotate-data.h | 7 +-
> tools/perf/util/annotate.c | 108 +--
> tools/perf/util/annotate.h | 12 +
> tools/perf/util/capstone.c | 107 ++-
> tools/perf/util/disasm.c | 5 +
> tools/perf/util/disasm.h | 5 +
> .../util/dwarf-regs-arch/dwarf-regs-arm64.c | 20 +
> tools/perf/util/dwarf-regs.c | 2 +-
> tools/perf/util/include/dwarf-regs.h | 1 +
> tools/perf/util/llvm.c | 50 ++
> 14 files changed, 984 insertions(+), 145 deletions(-)
>
>
> base-commit: cf7c3c02fdd0dfccf4d6611714273dcb538af2cb
> --
> 2.34.1
>