kernel.git/tools/perf/Documentation/perf-mem.txt, branch master

perf mem: Document new output fields (op, cache, mem, dtlb, snoop)

2025-06-16T17:05:10Z

Update the documentation of the new fields with examples and caveats. Also update the related documentation for AMD IBS. Reviewed-by: Ravi Bangoria Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250610005742.2173050-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf mem: Describe overhead calculation in brief

2025-05-28T17:41:10Z

Unlike perf-report which uses sample period for overhead calculation, perf-mem overhead is calculated using sample weight. Describe perf-mem overhead calculation method in it's man page. Reviewed-by: Leo Yan Signed-off-by: Ravi Bangoria Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Cc: Stephane Eranian Link: https://lore.kernel.org/r/20250523222157.1259998-1-namhyung@kernel.org Signed-off-by: Namhyung Kim Signed-off-by: Arnaldo Carvalho de Melo

perf mem/c2c amd: Add ldlat support

2025-04-30T01:30:46Z

'perf mem/c2c' uses IBS Op PMU on AMD platforms. IBS Op PMU on Zen5 uarch has added support for Load Latency filtering. Implement 'perf mem/c2c' --ldlat using IBS Op Load Latency filtering capability. Some subtle differences between AMD and other arch: o --ldlat is disabled by default on AMD o Supported values are 128 to 2048. Signed-off-by: Ravi Bangoria Cc: Ananth Narayan Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Joe Mario Cc: Kan Liang Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Sandipan Das Cc: Santosh Shukla Cc: Stephane Eranian Link: https://lore.kernel.org/r/20250429035938.1301-4-ravi.bangoria@amd.com Signed-off-by: Arnaldo Carvalho de Melo

perf mem: Update documentation for new options

2024-08-05T14:40:20Z

Add a common options section and move some items to the section. Also add description of new options to report options. Suggested-by: Ian Rogers Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Athira Rajeev Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Cc: Stephane Eranian Link: https://lore.kernel.org/lkml/20240802180913.1023886-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Fix typos

2024-05-29T05:52:28Z

Assorted typo fixes. Signed-off-by: Ian Rogers Reviewed-by: James Clark Cc: Changbin Du Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240521223555.858859-1-irogers@google.com

perf mem/c2c: Document that SPE is used for mem and c2c on ARM

2023-01-27T18:00:34Z

Setup is non-trivial so also link to the full SPE docs. Signed-off-by: James Clark Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Leo Yan Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: linux-perf-users@vger.kernel.or Link: https://lore.kernel.org/r/20230124145929.557891-1-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo

perf mem/c2c: Add load store event mappings for AMD

2022-10-06T19:30:06Z

The 'perf mem' and 'perf 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. Wire in the "ibs_op//" event as mem-ldst event for AMD. 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 $ [1]: https://lore.kernel.org/lkml/20220829113347.295-1-ravi.bangoria@amd.com Signed-off-by: Ravi Bangoria Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Ali Saidi Cc: Ananth Narayan Cc: Andi Kleen Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Ian Rogers Cc: Ingo Molnar Cc: Joe Mario Cc: Kan Liang Cc: Kim Phillips Cc: Leo Yan Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Sandipan Das Cc: Santosh Shukla Cc: Stephane Eranian Cc: Thomas Gleixner Cc: x86@kernel.org Link: https://lore.kernel.org/r/20221006153946.7816-6-ravi.bangoria@amd.com Signed-off-by: Arnaldo Carvalho de Melo

perf mem: Support data page size

2021-01-20T17:34:20Z

Add option --data-page-size in "perf mem" to record/report data page size. Here are some examples: # perf mem --phys-data --data-page-size report -D # PID, TID, IP, ADDR, PHYS ADDR, DATA PAGE SIZE, LOCAL WEIGHT, DSRC, SYMBOL 20134 20134 0xffffffffb5bd2fd0 0x016ffff9a274e96a308 0x000000044e96a308 4K 1168 0x5080144 /lib/modules/4.18.0-rc7+/build/vmlinux:perf_ctx_unlock 20134 20134 0xffffffffb63f645c 0xffffffffb752b814 0xcfb52b814 2M 225 0x26a100142 /lib/modules/4.18.0-rc7+/build/vmlinux:_raw_spin_lock 20134 20134 0xffffffffb660300c 0xfffffe00016b8bb0 0x0 4K 0 0x5080144 /lib/modules/4.18.0-rc7+/build/vmlinux:__x86_indirect_thunk_rax # # perf mem --phys-data --data-page-size report --stdio # To display the perf.data header info, please use # --header/--header-only options. # # # Total Lost Samples: 0 # # Samples: 5K of event 'cpu/mem-loads,ldlat=30/P' # Total weight : 281234 # Sort order : # mem,sym,dso,symbol_daddr,dso_daddr,tlb,locked,phys_daddr,data_page_size # # Overhead Samples Memory access Symbol Shared Object Data Symbol Data Object TLB access Locked Data Physical Address Data Page Size # ........ ....... ............. ............................ ................ ...................... ........... ............ ...... ...................... .............. 28.54% 1826 L1 or L1 hit [k] __x86_indirect_thunk_rax [kernel.vmlinux] [k] 0xffffb0df31b0ff28 [unknown] L1 or L2 hit No [k] 0x0000000000000000 4K 6.02% 256 L1 or L1 hit [.] touch_buffer dtlb [.] 0x00007ffd50109da8 [stack] L1 or L2 hit No [.] 0x000000042454ada8 4K 3.23% 5 L1 or L1 hit [k] clear_huge_page [kernel.vmlinux] [k] 0xffff9a2753b8ce60 [unknown] L1 or L2 hit No [k] 0x0000000453b8ce60 2M 2.98% 4 L1 or L1 hit [k] clear_page_erms [kernel.vmlinux] [k] 0xffffb0df31b0fd00 [unknown] L1 or L2 hit No [k] 0x0000000000000000 4K Signed-off-by: Kan Liang Acked-by: Jiri Olsa Acked-by: Namhyung Kim Cc: Andi Kleen Cc: Ingo Molnar Cc: Mark Rutland Cc: Michael Ellerman Cc: Stephane Eranian Cc: Will Deacon Link: https://lore.kernel.org/r/20210105195752.43489-3-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf mem/c2c: Fix perf_mem_events to support powerpc

2019-02-04T14:32:14Z

PowerPC hardware does not have a builtin latency filter (--ldlat) for the "mem-load" event and perf_mem_events by default includes "/ldlat=30/" which is causing a failure on PowerPC. Refactor the code to support "perf mem/c2c" on PowerPC. This patch depends on kernel side changes done my Madhavan: https://lists.ozlabs.org/pipermail/linuxppc-dev/2018-December/182596.html Signed-off-by: Ravi Bangoria Acked-by: Jiri Olsa Cc: Dick Fowles Cc: Don Zickus Cc: Joe Mario Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Namhyung Kim Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20190129132412.771-1-ravi.bangoria@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf mem: Document incorrect and missing options

2018-04-23T14:59:18Z

Several options were incorrectly described, some lacked describing required arguments while others were simply not documented, fix it. Signed-off-by: Sangwon Hong Acked-by: Jiri Olsa Cc: Namhyung Kim Cc: Taeung Song Link: http://lkml.kernel.org/r/1524382146-19609-1-git-send-email-qpakzk@gmail.com Signed-off-by: Arnaldo Carvalho de Melo