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

perf tools: Flush remaining samples w/o deferred callchains

2025-12-03T05:59:14+00:00

It's possible that some kernel samples don't have matching deferred callchain records when the profiling session was ended before the threads came back to userspace. Let's flush the samples before finish the session. Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

perf tools: Merge deferred user callchains

2025-12-03T05:59:14+00:00

Save samples with deferred callchains in a separate list and deliver them after merging the user callchains. If users don't want to merge they can set tool->merge_deferred_callchains to false to prevent the behavior. With previous result, now perf script will show the merged callchains. $ perf script ... pwd 2312 121.163435: 249113 cpu/cycles/P: ffffffff845b78d8 __build_id_parse.isra.0+0x218 ([kernel.kallsyms]) ffffffff83bb5bf6 perf_event_mmap+0x2e6 ([kernel.kallsyms]) ffffffff83c31959 mprotect_fixup+0x1e9 ([kernel.kallsyms]) ffffffff83c31dc5 do_mprotect_pkey+0x2b5 ([kernel.kallsyms]) ffffffff83c3206f __x64_sys_mprotect+0x1f ([kernel.kallsyms]) ffffffff845e6692 do_syscall_64+0x62 ([kernel.kallsyms]) ffffffff8360012f entry_SYSCALL_64_after_hwframe+0x76 ([kernel.kallsyms]) 7f18fe337fa7 mprotect+0x7 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) 7f18fe330e0f _dl_sysdep_start+0x7f (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) 7f18fe331448 _dl_start_user+0x0 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) ... The old output can be get using --no-merge-callchain option. Also perf report can get the user callchain entry at the end. $ perf report --no-children --stdio -q -S __build_id_parse.isra.0 # symbol: __build_id_parse.isra.0 8.40% pwd [kernel.kallsyms] | ---__build_id_parse.isra.0 perf_event_mmap mprotect_fixup do_mprotect_pkey __x64_sys_mprotect do_syscall_64 entry_SYSCALL_64_after_hwframe mprotect _dl_sysdep_start _dl_start_user Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

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 tool: Add the perf_tool argument to all callbacks

2025-11-07T21:25:05+00:00

Getting context for what a tool is doing, such as the perf_inject instance, using container_of the tool is a common pattern in the code. This isn't possible event_op2, event_op3 and event_op4 callbacks as the tool isn't passed. Add the argument and then fix function signatures to match. As tools maybe reading a tool from somewhere else, change that code to use the passed in tool. Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf session: Fix handling when buffer exceeds 2 GiB

2025-09-19T15:44:10+00:00

If a user specifies an AUX buffer larger than 2 GiB, the returned size may exceed 0x80000000. Since the err variable is defined as a signed 32-bit integer, such a value overflows and becomes negative. As a result, the perf record command reports an error: 0x146e8 [0x30]: failed to process type: 71 [Unknown error 183711232] Change the type of the err variable to a signed 64-bit integer to accommodate large buffer sizes correctly. Fixes: d5652d865ea734a1 ("perf session: Add ability to skip 4GiB or more") Reported-by: Tamas Zsoldos Signed-off-by: Leo Yan Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Jiri Olsa Link: https://lore.kernel.org/r/20250808-perf_fix_big_buffer_size-v1-1-45f45444a9a4@arm.com Signed-off-by: Arnaldo Carvalho de Melo

perf sample: Remove arch notion of sample parsing

2025-07-25T17:37:58+00:00

By definition arch sample parsing and synthesis will inhibit certain kinds of cross-platform record then analysis (report, script, etc.). Remove arch_perf_parse_sample_weight and arch_perf_synthesize_sample_weight replacing with a common implementation. Combine perf_sample p_stage_cyc and retire_lat as weight3 to capture the differing uses regardless of compiled for architecture. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-21-irogers@google.com Signed-off-by: Namhyung Kim

perf env: Remove global perf_env

2025-07-25T17:37:58+00:00

The global perf_env was used for the host, but if a perf_env wasn't easy to come by it was used in a lot of places where potentially recorded and host data could be confused. Remove the global variable as now the majority of accesses retrieve the perf_env for the host from the session. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-20-irogers@google.com Signed-off-by: Namhyung Kim

perf session: Add host_env argument to perf_session__new

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

When creating a perf_session the host perf_env may or may not want to be used. For example, `perf top` uses a host perf_env while `perf inject` does not. Add a host_env argument to perf_session__new so that sessions requiring a host perf_env can pass it in. Currently if none is specified the global perf_env variable is used, but this will change in later patches. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-14-irogers@google.com Signed-off-by: Namhyung Kim

perf evlist: Change env variable to session

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

The session holds a perf_env pointer env. In UI code container_of is used to turn the env to a session, but this assumes the session header's env is in use. Rather than a dubious container_of, hold the session in the evlist and derive the env from the session with evsel__env, perf_session__env, etc. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-11-irogers@google.com Signed-off-by: Namhyung Kim

perf session: Add accessor for session->header.env

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

The perf_env from the header in the session is frequently accessed, add an accessor function rather than access directly. Cache the value to avoid repeated calls. No behavioral change. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-10-irogers@google.com Signed-off-by: Namhyung Kim