From f4e3381648be205365cb475512ee536e108e060e Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Thu, 20 Nov 2025 15:48:00 -0800 Subject: perf tools: Minimal DEFERRED_CALLCHAIN support 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 --- tools/lib/perf/include/perf/event.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h index aa1e91c97a22..43a8cb04994f 100644 --- a/tools/lib/perf/include/perf/event.h +++ b/tools/lib/perf/include/perf/event.h @@ -151,6 +151,18 @@ struct perf_record_switch { __u32 next_prev_tid; }; +struct perf_record_callchain_deferred { + struct perf_event_header header; + /* + * This is to match kernel and (deferred) user stacks together. + * The kernel part will be in the sample callchain array after + * the PERF_CONTEXT_USER_DEFERRED entry. + */ + __u64 cookie; + __u64 nr; + __u64 ips[]; +}; + struct perf_record_header_attr { struct perf_event_header header; struct perf_event_attr attr; @@ -523,6 +535,7 @@ union perf_event { struct perf_record_read read; struct perf_record_throttle throttle; struct perf_record_sample sample; + struct perf_record_callchain_deferred callchain_deferred; struct perf_record_bpf_event bpf; struct perf_record_ksymbol ksymbol; struct perf_record_text_poke_event text_poke; -- cgit v1.2.3