diff options
Diffstat (limited to 'tools/perf/python/twatch.py')
| -rwxr-xr-x | tools/perf/python/twatch.py | 81 |
1 files changed, 40 insertions, 41 deletions
diff --git a/tools/perf/python/twatch.py b/tools/perf/python/twatch.py index 04f3db29b9bc..b0f1bf113162 100755 --- a/tools/perf/python/twatch.py +++ b/tools/perf/python/twatch.py @@ -1,5 +1,6 @@ #! /usr/bin/env python # SPDX-License-Identifier: GPL-2.0-only +"""Example to show how to enable a software event and track context switches.""" # -*- python -*- # -*- coding: utf-8 -*- # twatch - Experimental use of the perf python interface @@ -9,53 +10,51 @@ import perf def main(context_switch = 0, thread = -1): - cpus = perf.cpu_map() - threads = perf.thread_map(thread) - evsel = perf.evsel(type = perf.TYPE_SOFTWARE, - config = perf.COUNT_SW_DUMMY, - task = 1, comm = 1, mmap = 0, freq = 0, - wakeup_events = 1, watermark = 1, - sample_id_all = 1, context_switch = context_switch, - sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU) - - """What we want are just the PERF_RECORD_ lifetime events for threads, - using the default, PERF_TYPE_HARDWARE + PERF_COUNT_HW_CYCLES & freq=1 - (the default), makes perf reenable irq_vectors:local_timer_entry, when - disabling nohz, not good for some use cases where all we want is to get - threads comes and goes... So use (perf.TYPE_SOFTWARE, perf_COUNT_SW_DUMMY, - freq=0) instead.""" - - evsel.open(cpus = cpus, threads = threads); - evlist = perf.evlist(cpus, threads) - evlist.add(evsel) - evlist.mmap() - while True: - evlist.poll(timeout = -1) - for cpu in cpus: - event = evlist.read_on_cpu(cpu) - if not event: - continue - print("cpu: {0}, pid: {1}, tid: {2} {3}".format(event.sample_cpu, + cpus = perf.cpu_map() + threads = perf.thread_map(thread) + evsel = perf.evsel(type = perf.TYPE_SOFTWARE, + config = perf.COUNT_SW_DUMMY, + task = 1, comm = 1, mmap = 0, freq = 0, + wakeup_events = 1, watermark = 1, + sample_id_all = 1, context_switch = context_switch, + sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU) + + # What we want are just the PERF_RECORD_ lifetime events for threads, + # using the default, PERF_TYPE_HARDWARE + PERF_COUNT_HW_CYCLES & freq=1 + # (the default), makes perf reenable irq_vectors:local_timer_entry, when + # disabling nohz, not good for some use cases where all we want is to get + # threads comes and goes... So use (perf.TYPE_SOFTWARE, perf_COUNT_SW_DUMMY, + # freq=0) instead. + + evsel.open(cpus = cpus, threads = threads) + evlist = perf.evlist(cpus, threads) + evlist.add(evsel) + evlist.mmap() + while True: + evlist.poll(timeout = -1) + for cpu in cpus: + event = evlist.read_on_cpu(cpu) + if not event: + continue + print("cpu: {0}, pid: {1}, tid: {2} {3}".format(event.sample_cpu, event.sample_pid, event.sample_tid, event)) if __name__ == '__main__': - """ - To test the PERF_RECORD_SWITCH record, pick a pid and replace - in the following line. + # To test the PERF_RECORD_SWITCH record, pick a pid and replace + # in the following line. - Example output: + # Example output: -cpu: 3, pid: 31463, tid: 31593 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31593, switch_out: 1 } -cpu: 1, pid: 31463, tid: 31489 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31489, switch_out: 1 } -cpu: 2, pid: 31463, tid: 31496 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31496, switch_out: 1 } -cpu: 3, pid: 31463, tid: 31491 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31491, switch_out: 0 } + # cpu: 3, pid: 31463, tid: 31593 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31593, switch_out: 1 } + # cpu: 1, pid: 31463, tid: 31489 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31489, switch_out: 1 } + # cpu: 2, pid: 31463, tid: 31496 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31496, switch_out: 1 } + # cpu: 3, pid: 31463, tid: 31491 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31491, switch_out: 0 } + # + # It is possible as well to use event.misc & perf.PERF_RECORD_MISC_SWITCH_OUT + # to figure out if this is a context switch in or out of the monitored threads. - It is possible as well to use event.misc & perf.PERF_RECORD_MISC_SWITCH_OUT - to figure out if this is a context switch in or out of the monitored threads. - - If bored, please add command line option parsing support for these options :-) - """ - # main(context_switch = 1, thread = 31463) + # If bored, please add command line option parsing support for these options :-) + # # main(context_switch = 1, thread = 31463) main() |