[PATCH v3 3/3] perf script: extend misc field decoding with switch out event type

From: Alexey Budankov
Date: Mon Mar 26 2018 - 05:25:38 EST



Append 'p' sign to 'S' tag designating the type of context switch out event so
'Sp' means preemption context switch. Documentation is extended to cover
new presentation changes.

perf script --show-switch-events -F +misc -I -i perf.data:

hdparm 4073 [004] U 762.198265: 380194 cycles:ppp: 7faf727f5a23 strchr (/usr/lib64/ld-2.26.so)
hdparm 4073 [004] K 762.198366: 441572 cycles:ppp: ffffffffb9218435 alloc_set_pte (/lib/modules/4.16.0-rc6+/build/vmlinux)
hdparm 4073 [004] S 762.198391: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0
swapper 0 [004] 762.198392: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 4073/4073
swapper 0 [004] Sp 762.198477: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 4073/4073
hdparm 4073 [004] 762.198478: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
swapper 0 [007] K 762.198514: 2303073 cycles:ppp: ffffffffb98b0c66 intel_idle (/lib/modules/4.16.0-rc6+/build/vmlinux)
swapper 0 [007] Sp 762.198561: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 1134/1134
kworker/u16:18 1134 [007] 762.198562: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
kworker/u16:18 1134 [007] S 762.198567: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 0/0

Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
---
tools/perf/Documentation/perf-script.txt | 17 +++++++++--------
tools/perf/builtin-script.c | 5 ++++-
2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index 36ec0257f8d3..afdafe2110a1 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -228,14 +228,15 @@ OPTIONS
For sample events it's possible to display misc field with -F +misc option,
following letters are displayed for each bit:

- PERF_RECORD_MISC_KERNEL K
- PERF_RECORD_MISC_USER U
- PERF_RECORD_MISC_HYPERVISOR H
- PERF_RECORD_MISC_GUEST_KERNEL G
- PERF_RECORD_MISC_GUEST_USER g
- PERF_RECORD_MISC_MMAP_DATA* M
- PERF_RECORD_MISC_COMM_EXEC E
- PERF_RECORD_MISC_SWITCH_OUT S
+ PERF_RECORD_MISC_KERNEL K
+ PERF_RECORD_MISC_USER U
+ PERF_RECORD_MISC_HYPERVISOR H
+ PERF_RECORD_MISC_GUEST_KERNEL G
+ PERF_RECORD_MISC_GUEST_USER g
+ PERF_RECORD_MISC_MMAP_DATA* M
+ PERF_RECORD_MISC_COMM_EXEC E
+ PERF_RECORD_MISC_SWITCH_OUT S
+ PERF_RECORD_MISC_SWITCH_OUT_PREEMPT Sp

$ perf script -F +misc ...
sched-messaging 1414 K 28690.636582: 4590 cycles ...
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 313c42423393..0f916e8e1835 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -657,8 +657,11 @@ static int perf_sample__fprintf_start(struct perf_sample *sample,
break;
case PERF_RECORD_SWITCH:
case PERF_RECORD_SWITCH_CPU_WIDE:
- if (has(SWITCH_OUT))
+ if (has(SWITCH_OUT)) {
ret += fprintf(fp, "S");
+ if (sample->misc & PERF_RECORD_MISC_SWITCH_OUT_PREEMPT)
+ ret += fprintf(fp, "p");
+ }
default:
break;
}