Re: [PATCH v2 00/16] perf arm64: Support data type profiling
From: James Clark
Date: Mon Apr 20 2026 - 05:31:56 EST
On 17/04/2026 02:53, Tengda Wu wrote:
On 2026/4/16 23:31, James Clark wrote:
On 03/04/2026 10:47, 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.
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.
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
Hi Tengda,
Did you run this with any itrace options? If I run your command I get repeated blocks of duplicate stats and types, which is very confusing. One for each sample type that we generate decoding SPE.
For example the default perf report output has all these groups:
Available samples
0 arm_spe_0/
ts_enable=1,pa_enable=1,load_filter=1,store_filter=1,min_latency=30/
0 dummy:u
3 l1d-miss
18 l1d-access
0 llc-miss
0 llc-access
0 tlb-miss
22 tlb-access
0 branch
0 remote-access
22 memory
22 instructions
Obviously there are 22 samples total (instructions) and they get duplicated into whatever other categories they happen to have flags for.
Yes, I agree. The duplication makes the type stats misleading.
De-duplication is definitely necessary here.
To remove the duplicates you have to do --itrace=i1i. Could that need to be default for perf annotate with SPE?I'll look into making this the default behavior for SPE data-type
annotation.
Annotate data type stats:
total 6204, ok 5091 (82.1%), bad 1113 (17.9%)
-----------------------------------------------------------
29 : no_sym
196 : no_var
806 : no_typeinfo
82 : bad_offset
1370 : insn_track
Here are the results with --itrace=i1i (a slight decrease in accuracy):
Annotate data type stats:
total 1138, ok 877 (77.1%), bad 261 (22.9%)
I'm still it a bit confused why you seem to get a 'total' count that is a sum of all the sample groups, if it went from 6204 to 1138 when you only asked for the instructions samples. Whereas I get separate groups, and asking for only instructions samples doesn't change the value for the last 'total', it just removes the other outputs.
It shouldn't change the accuracy either because the instruction group is the top level one which contains all of the samples.
-----------------------------------------------------------
6 : no_sym
44 : no_var
197 : no_typeinfo
14 : bad_offset
238 : insn_track
This will be the new baseline, and I will work on further optimizations
from here.
Best regards,
Tengda
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