kernel/linux.git/tools/perf/util/machine.c, branch v6.19.11

perf tools: Minimal DEFERRED_CALLCHAIN support

2025-12-03T00:13:32+00:00

Add a new event type for deferred callchains and a new callback for the struct perf_tool. For now it doesn't actually handle the deferred callchains but it just marks the sample if it has the PERF_CONTEXT_ USER_DEFFERED in the callchain array. At least, perf report can dump the raw data with this change. Actually this requires the next commit to enable attr.defer_callchain, but if you already have a data file, it'll show the following result. $ perf report -D ... 0x2158@perf.data [0x40]: event: 22 . . ... raw event: size 64 bytes . 0000: 16 00 00 00 02 00 40 00 06 00 00 00 0b 00 00 00 ......@......... . 0010: 03 00 00 00 00 00 00 00 a7 7f 33 fe 18 7f 00 00 ..........3..... . 0020: 0f 0e 33 fe 18 7f 00 00 48 14 33 fe 18 7f 00 00 ..3.....H.3..... . 0030: 08 09 00 00 08 09 00 00 e6 7a e7 35 1c 00 00 00 .........z.5.... 121163447014 0x2158 [0x40]: PERF_RECORD_CALLCHAIN_DEFERRED(IP, 0x2): 2312/2312: 0xb00000006 ... FP chain: nr:3 ..... 0: 00007f18fe337fa7 ..... 1: 00007f18fe330e0f ..... 2: 00007f18fe331448 : unhandled! Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

perf machine: Explicitly pass in host perf_env

2025-07-25T17:37:57+00:00

When creating a machine for the host explicitly pass in a scoped perf_env. This removes a use of the global perf_env. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-17-irogers@google.com Signed-off-by: Namhyung Kim

perf dso: Move build_id to dso_id

2025-07-25T17:37:56+00:00

The dso_id previously contained the major, minor, inode and inode generation information from a mmap2 event - the inode generation would be zero when reading from /proc/pid/maps. The build_id was in the dso. With build ID mmap2 events these fields wouldn't be initialized which would largely mean the special empty case where any dso would match for equality. This isn't desirable as if a dso is replaced we want the comparison to yield a difference. To support detecting the difference between DSOs based on build_id, move the build_id out of the DSO and into the dso_id. The dso_id is also stored in the DSO so nothing is lost. Capture in the dso_id what parts have been initialized and rename dso_id__inject to dso_id__improve_id so that it is clear the dso_id is being improved upon with additional information. With the build_id in the dso_id, use memcmp to compare for equality. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-7-irogers@google.com Signed-off-by: Namhyung Kim

perf callchain: Always populate the addr_location map when adding IP

2025-05-31T11:58:30+00:00

Dropping symbols also meant the callchain maps wasn't populated, but the callchain map is needed to find the DSO. Plumb the symbols option better, falling back to thread__find_map() rather than thread__find_symbol() when symbols are disabled. Fixes: 02b2705017d2e5ad ("perf callchain: Allow symbols to be optional when resolving a callchain") Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Athira Rajeev Cc: Ben Gainey Cc: Chaitanya S Prakash Cc: Charlie Jenkins Cc: Chun-Tse Shao Cc: Colin Ian King Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Graham Woodward Cc: Howard Chu Cc: Ilkka Koskinen Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: John Garry Cc: Kajol Jain Cc: Kan Liang Cc: Krzysztof Łopatowski Cc: Leo Yan Cc: Levi Yun Cc: Li Huafei Cc: linux-arm-kernel@lists.infradead.org Cc: Mark Rutland Cc: Martin Liška Cc: Masami Hiramatsu Cc: Matt Fleming Cc: Mike Leach Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Song Liu Cc: Steinar H. Gunderson Cc: Stephen Brennan Cc: Steve Clevenger Cc: Thomas Falcon Cc: Veronika Molnarova Cc: Weilin Wang Cc: Will Deacon Cc: Yicong Yang Cc: Yujie Liu Cc: Zhongqiu Han Cc: Zixian Cai Link: https://lore.kernel.org/r/20250529044000.759937-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Factor creating a "live" machine out of dwarf-unwind

2025-05-28T12:24:59+00:00

Factor out for use in places other than the dwarf unwinding tests for libunwind. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Anne Macedo Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Michael Petlan Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Yicong Yang Link: https://lore.kernel.org/r/20250313052952.871958-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf report: Do not process non-JIT BPF ksymbol events

2025-03-07T00:00:25+00:00

The length of PERF_RECORD_KSYMBOL for BPF is a size of JITed code so it'd be 0 when it's not JITed. The ksymbol is needed to symbolize the code when it gets samples in the region but non-JITed code cannot get samples. Thus it'd be ok to ignore them. Actually it caused a performance issue in the perf tools on old ARM kernels where it can refuse to JIT some BPF codes. It ended up splitting the existing kernel map (kallsyms). And later lookup for a kernel symbol would create a new kernel map from kallsyms and then split it again and again. :( Probably there's a bug in the kernel map/symbol handling in perf tools. But I think we need to fix this anyway. Reported-by: Kevin Nomura Acked-by: Song Liu Link: https://lore.kernel.org/r/20250305232838.128692-1-namhyung@kernel.org Signed-off-by: Namhyung Kim

perf machine: Fix insertion of PERF_RECORD_KSYMBOL related kernel maps

2025-03-06T07:04:07+00:00

This was detected at the end of a 'perf record' session when build-id collection was enabled and thus the BPF programs put in place while the session was running, some even put in place by perf itself were processed and inserted, with some overlaps related to BPF trampolines and programs took place. Using maps__fixup_overlap_and_insert() instead of maps__insert() "fixes" the problem, in the sense that overlaps will be dealt with and then the consistency will be kept, but it would be interesting to fully understand why such overlaps take place and how to deal with them when doing symbol resolution. Reported-by: Arnaldo Carvalho de Melo Suggested-by: Ian Rogers Tested-by: Arnaldo Carvalho de Melo Reviewed-by: Ian Rogers Link: https://lore.kernel.org/lkml/CAP-5=fXEEMFgPF2aZhKsfrY_En+qoqX20dWfuE_ad73Uxf0ZHQ@mail.gmail.com Link: https://lore.kernel.org/r/20250228211734.33781-7-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim

perf machine: Fixup kernel maps ends after adding extra maps

2025-03-06T07:03:15+00:00

I just noticed it would add extra kernel maps after modules. I think it should fixup end address of the kernel maps after adding all maps first. Fixes: 876e80cf83d10585 ("perf tools: Fixup end address of modules") Reported-by: Arnaldo Carvalho de Melo Tested-by: Arnaldo Carvalho de Melo Reviewed-by: Ian Rogers Link: https://lore.kernel.org/lkml/Z7TvZGjVix2asYWI@x1 Link: https://lore.kernel.org/lkml/Z712hzvv22Ni63f1@google.com Link: https://lore.kernel.org/r/20250228211734.33781-4-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim

perf machine: Reuse module path buffer

2025-02-24T23:46:33+00:00

Rather than copying the path and appending the directory entry in a fresh path buffer, append to the path at the end of where it is for the recursion level. This saves a PATH_MAX buffer per recursion level and some unnecessary copying. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250222061015.303622-9-irogers@google.com Signed-off-by: Namhyung Kim

perf maps: Switch modules tree walk to io_dir__readdir

2025-02-24T23:46:33+00:00

Compared to glibc's opendir/readdir this lowers the max RSS of perf record by 1.8MB on a Debian machine. Acked-by: Namhyung Kim Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250222061015.303622-3-irogers@google.com Signed-off-by: Namhyung Kim