Messages in this thread | | | From | Ravi Bangoria <> | Subject | [PATCH v2 00/14] perf mem/c2c: Add support for AMD | Date | Thu, 16 Jun 2022 17:06:23 +0530 |
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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
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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