Re: [PATCH v5 0/6] perf: Add support for memory region/range reporting

[Namhyung Kim]

Hello,

On Thu, Aug 20, 2026 at 07:18:13PM -0500, Thomas Falcon wrote:
> Add support for two memory-related reporting features in the perf tool:
> 
> 1. Memory region reporting in perf-c2c and perf-script subcommands.
> 2. Memory range data in perf.data file header and perf-c2c subcommand.
> 
> Memory region reporting was introduced as part of support for the
> Off-module Response facility (OMR) [1], which provides a new data
> source encoding supporting "up to 8 fine-grained memory regions in
> addition to the cache region, offering more detailed insights into
> memory access regions."
> 
> Memory Range support was introduced with the addition of the ACPI Memory
> Range and Region Mapping (MRRM) [2] table. It provides a base address plus
> a length value for each memory range, as well as NUMA node and local and
> remote "region ID's" so that "platform firmware can indicate the type of
> memory for each range."[3]
> 
> Include a change allowing PERF_MEM_LVLNUM_L0 to be printed in
> perf-mem output as well.
> 
> [1]: https://lore.kernel.org/all/20260114011750.350569-1-dapeng1.mi@xxxxxxxxxxxxxxx/
> [2]: https://lore.kernel.org/lkml/20250505173819.419271-1-tony.luck@xxxxxxxxx/
> [3]: MRRM definition allow for future expansion for the OS to assign
> these region IDs.

Thank you for doing this.  Unfortunately it conflicts with Jiebin's perf
c2c function view support patchset.  As there's an update, can you please
wait a little more and rebase onto the latest perf-tools-next?

Thanks,
Namhyung

> 
> v5:
> -- perf-c2c: make the cacheline header span and ui_quirks() width
>    fixup depend on memory-region availability (Namhyung Kim)
> 
> v4:
> -- perf-script: gate the Region field on the HEADER_MEMORY_RANGES feature
>    bit via perf_session instead of a global flag, with a pipe-mode fallback
> -- perf-c2c: fix output_str allocation error handling
> -- perf header: Fix typo in region id bounds checking which made region 255
>    invalid
> 
> v3:
> -- included missing ff-size check in process_memory_ranges
> -- make memory region reporting in perf c2c-and perf-script conditional
>    on feature bit, requiring some patch reordering (Namhyung Kim)
> -- used open/openat to read memory range sysfs files in memory_range__read()
>    (Namhyung Kim)
> -- Removed path name and file name buffers in memory_range__read(),
>    instead pass path name from as a parameter from memory_range__parse()
>    (Namhyung Kim)
> -- use calloc instead of zalloc in memory_range__parse() and
>    process_memory_ranges() (Namhyung Kim)
> -- Removed redundant check for existance of memory range directory in
>    memory_range__read() (Namhyung Kim)
> -- Included output examples of memory ranges in perf header and perf-c2c
>    in commit message (Namhyung Kim)
> 
> v2:
> -- Added missing newline in WARN_ONCE message in c2c_he__set_mem_region()
> -- increased buffers passed to perf_script__meminfo_scnprintf() from 150
>    to 200 bytes to avoid silent truncation
> -- Added check for NULL return of sysfs__mountpoint() when parsing
>    memory ranges in sysfs
> -- increased MAX_MEMORY_RANGES sanity check from 64 to 256 based on
>    ACPI MRRM table implementation in Linux kernel
> -- added comment for MAX_MEMORY_RANGES to clarify that it is a sanity check
>    for malformed perf.data files
> -- removed a line of code was removed from util/env.h but was added back in
>    v1 due to bad rebase
> 
> Dapeng Mi (3):
>   perf mem: Add support for printing PERF_MEM_LVLNUM_L0
>   perf tools: Show memory region in perf-c2c subcommand
>   perf tools: Show memory region in perf-script subcommand
> 
> Thomas Falcon (3):
>   perf mem: Fix size tracking for mem_lvl's in
>     perf_script__meminfo_scnprintf()
>   perf header: Support memory ranges
>   perf c2c: print memory region data with stdio output
> 
>  tools/perf/Documentation/perf-record.txt      |   2 +-
>  .../Documentation/perf.data-file-format.txt   |  13 ++
>  tools/perf/builtin-c2c.c                      | 125 ++++++++++-
>  tools/perf/builtin-inject.c                   |   1 +
>  tools/perf/builtin-script.c                   |  13 +-
>  tools/perf/util/bpf-filter.l                  |   1 +
>  tools/perf/util/env.c                         |   1 +
>  tools/perf/util/env.h                         |  10 +
>  tools/perf/util/header.c                      | 203 ++++++++++++++++++
>  tools/perf/util/header.h                      |   1 +
>  tools/perf/util/mem-events.c                  |  93 +++++++-
>  tools/perf/util/mem-events.h                  |   5 +-
>  .../scripting-engines/trace-event-python.c    |   5 +-
>  13 files changed, 452 insertions(+), 21 deletions(-)
> 
> -- 
> 2.55.0
>