On Fri, Aug 7, 2026 at 10:11 PM Athira Rajeev <[email protected]> wrote: > > > > > On 7 Aug 2026, at 8:11 PM, Athira Rajeev <[email protected]> wrote: > > > > Overview: > > This series adds perf tool support for capturing and processing Hardware > > Trace Macro (HTM) trace data on POWER systems. HTM exposes raw bus-trace > > data via the H_HTM hypervisor call. The kernel-side HTM PMU driver > > (submitted separately) streams this data into perf AUX buffers and emits > > memory configuration as PERF_SAMPLE_RAW records. > > > > This series wires up the record and report sides in the perf tool so that > > 'perf record' collects HTM data and 'perf report' writes the trace and > > memory configuration to files ready for post-processing with htmdecode. > > > > Hi All, > > I am currently working on addressing Sashiko's review comments for V5 of the > patch series. > Before I proceed with posting V6, requesting for any feedback or suggestions > that I should incorporate in V6, apart from Sashiko's comments.
Hi Athira, Did you get what you needed for V6? I see Adrian's reviews. Thanks, Ian > Thanks > Athira > > > Patch overview: > > Patch 1 refactors the existing powerpc auxtrace dispatch. All VPA-DTL > > recording logic is moved from arch/powerpc/util/auxtrace.c into its own > > file, arch/powerpc/util/vpa-dtl.c, leaving auxtrace_record__init() as a > > thin per-PMU dispatcher. This is a prerequisite for adding the HTM > > recording path cleanly. > > > > Patch 2 adds the HTM recording path (arch/powerpc/util/htm.c and > > util/powerpc-htm.h). htm_recording_init() sets up the auxtrace_record > > callbacks. htm_info_fill() stores the PMU type and a (cpu, attr.config) > > pair for each htm evsel into the PERF_RECORD_AUXTRACE_INFO priv[] area. > > The decode side reads these back to map each AUX buffer to its > > (node, chip, core) target using event->auxtrace.cpu. PERF_SAMPLE_RAW is > > also enabled here so that memory configuration records are captured > > alongside the AUX stream. > > > > Patch 3 adds a generic weak arch_perf_record__need_read() hook in > > builtin-record.c. When the hook returns non-zero, perf record performs > > an extra mmap-read pass before disabling events. The drain loop runs > > until the hook returns 0 or no forward progress is made, then the events > > are disabled and closed normally. > > > > Patch 4 implements arch_perf_record__need_read() for powerpc. It reads > > event->count for all open htm evsels via perf_evsel__read() and > > accumulates the values. The kernel driver sets this count to the number > > of 128-byte HTM trace records written on a successful dump, 1 when the > > AUX buffer is temporarily full but the hypervisor stream is intact, and > > 0 once the stream is exhausted or a hard error occurs. A non-zero total > > causes the recording loop to perform another read pass. > > > > Patch 5 adds PERF_AUXTRACE_POWERPC_HTM to the auxtrace_type enum and > > wires the dispatch in perf_event__process_auxtrace_info(). It also > > amends htm_info_fill() to set auxtrace_info->type now that the constant > > is available. > > > > Patch 6 adds the full HTM decode path in util/powerpc-htm.c. > > powerpc_htm_process_auxtrace_info() reads the (cpu, config) pairs from > > priv[] and builds a cpu_configs[] lookup table. As each > > PERF_RECORD_AUXTRACE event arrives, process_auxtrace_event() maps it to > > the correct target and writes the data to htm.bin.nX.pX.cX.tX immediately. > > PERF_RECORD_SAMPLE RAW records are written to translation.nX.pX.cX.tX by > > process_event(). Per-run first-write tracking (htm_target_seen) ensures > > O_TRUNC on the first write and O_APPEND on subsequent writes. > > > > Patches not included in V2: > > Three patches present in V1 are intentionally dropped from this series > > and will be submitted as a follow-on once the core infrastructure gets > > integrated: > > > > - htmdecode integration: V1 patch 6 invoked the external htmdecode > > tool via fork/exec after writing htm.bin.* to decode the raw > > bus-trace data in-process. This is deferred because the interface > > between perf and an external decode tool needs more discussion. > > > > - Physical-to-logical address mapping: V1 patch 7 read the current > > partition ID from /proc/powerpc/lparcfg, parsed the translation.* > > memory map entries, and mapped physical addresses in the decoded > > trace to logical addresses within the LPAR. > > > > - Synthetic sample generation: V1 patches 8 and 9 created a > > PERF_TYPE_SYNTH event named "htm", injected synthetic perf samples > > with the translated logical addresses as sample IP, and wrote a > > separate .out.l file with logical addresses alongside the decoded > > trace. The appropriate abstraction for synthetic HTM samples in the > > perf tool requires further discussion. > > > > Usage example: > > Collect HTM trace data from a single chip target: > > > > # perf record -C 9 -m,256 \ > > -e htm/nodalchipindex=2,nodeindex=0,htm_type=1/ sleep 3 > > [ perf record: Woken up 1 times to write data ] > > [ perf record: Captured and wrote 256.277 MB perf.data ] > > > > # perf report > > > > Output files written by perf report: > > > > htm.bin.n0.p2.c0.t1 raw HTM bus-trace data > > translation.n0.p2.c0.t1 memory configuration records > > > > Multiple targets can be collected simultaneously: > > > > # perf record -m,256 \ > > -e htm/nodalchipindex=2,nodeindex=0,htm_type=1,cpu=8/ \ > > -e htm/nodalchipindex=1,nodeindex=0,htm_type=1,cpu=9/ \ > > -a sleep 10 > > > > Testing: > > Tested on POWER11. Both htm.bin.* and translation.* files are produced > > correctly for single and dual target collection. > > > > Note: Link to kernel patches: > > https://lore.kernel.org/linuxppc-dev/[email protected]/T/#t > > > > Athira Rajeev (6): > > tools/perf: Move powerpc VPA-DTL auxtrace init into a separate file > > tools/perf: Add AUXTRACE recording support for powerpc HTM > > tools/perf: Add arch hook to drain remaining data before event close > > tools/perf: Add powerpc callback support for > > arch_perf_record__need_read > > tools/perf: Add powerpc HTM auxtrace event processing support > > tools/perf: Add perf tool support for processing powerpc HTM AUXTRACE > > records > > > > tools/perf/arch/powerpc/util/Build | 2 + > > tools/perf/arch/powerpc/util/auxtrace.c | 98 ++---- > > tools/perf/arch/powerpc/util/evsel.c | 77 ++++ > > tools/perf/arch/powerpc/util/htm.c | 185 ++++++++++ > > tools/perf/arch/powerpc/util/vpa-dtl.c | 96 +++++ > > tools/perf/builtin-record.c | 65 ++++ > > tools/perf/util/Build | 1 + > > tools/perf/util/auxtrace.c | 4 + > > tools/perf/util/auxtrace.h | 1 + > > tools/perf/util/powerpc-htm.c | 447 ++++++++++++++++++++++++ > > tools/perf/util/powerpc-htm.h | 43 +++ > > tools/perf/util/powerpc-vpadtl.h | 3 + > > tools/perf/util/record.h | 4 + > > 13 files changed, 954 insertions(+), 72 deletions(-) > > create mode 100644 tools/perf/arch/powerpc/util/htm.c > > create mode 100644 tools/perf/arch/powerpc/util/vpa-dtl.c > > create mode 100644 tools/perf/util/powerpc-htm.c > > create mode 100644 tools/perf/util/powerpc-htm.h > > > > -- > > 2.53.0 > > >
