[PATCH v3 00/15] perf mem/c2c: Add support for AMD

Ravi Bangoria
2022-09-28T09:58:41Z

Perf mem and c2c tools are wrappers around perf record with mem load/
store events. IBS tagged load/store sample provides most of the
information needed for these tools. Enable support for these tools on
AMD Zen processors based on IBS Op pmu.

There are some limitations though: Only load/store micro-ops provide
mem/c2c information. Whereas, IBS does not have a way to choose a
particular type of micro-op to tag. This results in many non-LS
micro-ops being tagged which appear as N/A in the perf report. IBS,
being an uncore pmu from kernel point of view[1], does not support per
process monitoring. Thus, perf mem/c2c on AMD are currently supported
in per-cpu mode only.

Example:
$ sudo ./perf mem record -- -c 10000
^C[ perf record: Woken up 227 times to write data ]
[ perf record: Captured and wrote 58.760 MB perf.data (836978 samples) ]

$ sudo ./perf mem report -F mem,sample,snoop
Samples: 836K of event 'ibs_op//', Event count (approx.): 8418762
Memory access Samples Snoop
N/A 700620 N/A
L1 hit 126675 N/A
L2 hit 424 N/A
L3 hit 664 HitM
L3 hit 10 N/A
Local RAM hit 2 N/A
Remote RAM (1 hop) hit 8558 N/A
Remote Cache (1 hop) hit 3 N/A
Remote Cache (1 hop) hit 2 HitM
Remote Cache (2 hops) hit 10 HitM
Remote Cache (2 hops) hit 6 N/A
Uncached hit 4 N/A

Prepared on queue/perf/core (cce6a2d7e0e49).

v2: https://lore.kernel.org/all/20220616113638.900-1-ravi.bangoria@amd.com
v2->v3:
- Use sample_flags instead of __PERF_SAMPLE_*_EARLY varients
- Make PERF_SAMPLE_WEIGHT independent of PERF_SAMPLE_DATA_SRC
- Add a patch to reverse sync PERF_MEM_SNOOPX_PEER from tools
to kernel uapi header
- Add Acked-by: Jiri Olsa for tool side unchanged patches

Also, a recent patch[2] to test perf mem fails on AMD because of
aforementioned limitations.

[1]: https://lore.kernel.org/lkml/20220829113347.295-1-ravi.bangoria@amd.com
[2]: https://lore.kernel.org/lkml/20220924133408.1125903-1-leo.yan%40linaro.org

Ravi Bangoria (15):
perf/mem: Introduce PERF_MEM_LVLNUM_{EXTN_MEM|IO}
perf/x86/amd: Add IBS OP_DATA2 DataSrc bit definitions
perf/x86/amd: Support PERF_SAMPLE_DATA_SRC
perf/x86/amd: Support PERF_SAMPLE_{WEIGHT|WEIGHT_STRUCT}
perf/x86/amd: Support PERF_SAMPLE_ADDR
perf/x86/amd: Support PERF_SAMPLE_PHY_ADDR
perf/uapi: Define PERF_MEM_SNOOPX_PEER in kernel header file
perf tool: Sync include/uapi/linux/perf_event.h header
perf tool: Sync arch/x86/include/asm/amd-ibs.h header
perf mem: Add support for printing PERF_MEM_LVLNUM_{EXTN_MEM|IO}
perf mem/c2c: Set PERF_SAMPLE_WEIGHT for LOAD_STORE events
perf mem/c2c: Add load store event mappings for AMD
perf mem/c2c: Avoid printing empty lines for unsupported events
perf mem: Use more generic term for LFB
perf script: Add missing fields in usage hint

arch/x86/events/amd/ibs.c | 345 ++++++++++++++++++++++-
arch/x86/include/asm/amd-ibs.h | 16 ++
include/uapi/linux/perf_event.h | 6 +-
kernel/events/core.c | 3 +-
tools/arch/x86/include/asm/amd-ibs.h | 16 ++
tools/include/uapi/linux/perf_event.h | 4 +-
tools/perf/Documentation/perf-c2c.txt | 14 +-
tools/perf/Documentation/perf-mem.txt | 3 +-
tools/perf/Documentation/perf-record.txt | 1 +
tools/perf/arch/x86/util/mem-events.c | 31 +-
tools/perf/builtin-c2c.c | 1 +
tools/perf/builtin-mem.c | 1 +
tools/perf/builtin-script.c | 7 +-
tools/perf/util/mem-events.c | 17 +-
14 files changed, 438 insertions(+), 27 deletions(-)

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2.31.1