Print additional 'yield' tag for PERF_RECORD_SWITCH[_CPU_WIDE] OUT records when event header misc field contains PERF_RECORD_MISC_SWITCH_OUT_YIELD bit set designating synchronization context switch out event:
perf report -D -i system-wide.perf: ... 0x1b9c50 [0x30]: event: 15 . . ... raw event: size 48 bytes . 0000: 0f 00 00 00 00 20 30 00 01 1e 00 00 01 1e 00 00 ..... 0......... . 0010: 00 00 00 00 00 00 00 00 85 ae d4 e3 3e 0e 00 00 ............>... . 0020: 54 00 00 00 00 00 00 00 05 00 00 00 00 00 00 00 T............... 5 15663273127557 0x1b9c50 [0x30]: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 7681/7681 0x2646c0 [0x30]: event: 15 . . ... raw event: size 48 bytes . 0000: 0f 00 00 00 00 60 30 00 00 00 00 00 00 00 00 00 .....`0......... . 0010: 00 1e 00 00 00 1e 00 00 29 1e d5 e3 3e 0e 00 00 ........)...>... . 0020: 56 00 00 00 00 00 00 00 07 00 00 00 00 00 00 00 V............... 7 15663273156137 0x2646c0 [0x30]: PERF_RECORD_SWITCH_CPU_WIDE OUT yield next pid/tid: 0/0 ... Signed-off-by: Alexey Budankov <[email protected]> --- tools/include/uapi/linux/perf_event.h | 5 +++++ tools/perf/util/event.c | 4 +++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h index 6f873503552d..0339c829cda5 100644 --- a/tools/include/uapi/linux/perf_event.h +++ b/tools/include/uapi/linux/perf_event.h @@ -654,6 +654,11 @@ struct perf_event_mmap_page { * perf_event_attr::precise_ip. */ #define PERF_RECORD_MISC_EXACT_IP (1 << 14) +/* + * Indicates that thread explicitly yielded cpu due to + * a call of some synchronization API e.g. futex system call + */ +#define PERF_RECORD_MISC_SWITCH_OUT_YIELD (1 << 14) /* * Reserve the last bit to indicate some extended misc field */ diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index f0a6cbd033cc..af5a85d56446 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -1421,7 +1421,9 @@ size_t perf_event__fprintf_itrace_start(union perf_event *event, FILE *fp) size_t perf_event__fprintf_switch(union perf_event *event, FILE *fp) { bool out = event->header.misc & PERF_RECORD_MISC_SWITCH_OUT; - const char *in_out = out ? "OUT" : "IN "; + const char *in_out = !out ? "IN " : + !(event->header.misc & PERF_RECORD_MISC_SWITCH_OUT_YIELD) ? + "OUT" : "OUT yield"; if (event->header.type == PERF_RECORD_SWITCH) return fprintf(fp, " %s\n", in_out);
