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SubjectRe: [PATCH v2 00/14] perf mem/c2c: Add support for AMD
On Thu, Jun 16, 2022 at 05:06:23PM +0530, Ravi Bangoria wrote:
> 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 instructions provide
> mem/c2c information. However, IBS does not provide a way to choose a
> particular type of instruction to tag. This results in many non-LS
> instructions being tagged which appear as N/A. 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 amd/perf/core (9886142c7a22) + IBS Zen4 enhancement patches[2]
>
> [1]: https://lore.kernel.org/lkml/20220113134743.1292-1-ravi.bangoria@amd.com
> [2]: https://lore.kernel.org/lkml/20220604044519.594-1-ravi.bangoria@amd.com
>
> v1: https://lore.kernel.org/lkml/20220525093938.4101-1-ravi.bangoria@amd.com
> v1->v2:
> - Instead of defining macros to extract IBS register bits, use existing
> bitfield definitions. Zen4 has introduced additional set of bits in
> IBS registers which this series also exploits and thus this series
> now depends on IBS Zen4 enhancement patchset.
> - Add support for PERF_SAMPLE_WEIGHT_STRUCT. While opening a new event,
> perf tool starts with a set of attributes and goes on reverting some
> attributes in a predefined order until it succeeds or run out or all
> attempts. Here, 1st attempt includes WEIGHT_STRUCT and exclude_guest
> which always fails because IBS does not support guest filtering. The
> problem however is, perf reverts WEIGHT_STRUCT but keeps trying with
> exclude_guest. Thus, although, this series enables WEIGHT_STRUCT
> support from kernel, using it from the perf tool need more changes.
> I'll try to address this bug later.
> - Introduce __PERF_SAMPLE_CALLCHAIN_EARLY to hint generic perf driver
> that physical address is set by arch pmu driver and should not be
> overwritten.
>
>
> Ravi Bangoria (14):
> 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 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

tools part looks good to me

Acked-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka

>
> arch/x86/events/amd/ibs.c | 372 ++++++++++++++++++++++-
> arch/x86/include/asm/amd-ibs.h | 16 +
> include/uapi/linux/perf_event.h | 5 +-
> kernel/events/core.c | 4 +-
> tools/arch/x86/include/asm/amd-ibs.h | 16 +
> tools/include/uapi/linux/perf_event.h | 5 +-
> 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, 467 insertions(+), 26 deletions(-)
>
> --
> 2.31.1
>

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