These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / tools / perf / python / twatch.py

diff --git a/kernel/tools/perf/python/twatch.py b/kernel/tools/perf/python/twatch.py
index 2225162..c235c22 100755 (executable)
--- a/kernel/tools/perf/python/twatch.py
+++ b/kernel/tools/perf/python/twatch.py
@@ -15,13 +15,23 @@
 
 import perf
 
-def main():
+def main(context_switch = 0, thread = -1):
        cpus = perf.cpu_map()
-       threads = perf.thread_map()
-       evsel = perf.evsel(task = 1, comm = 1, mmap = 0,
+       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,
+                          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)
@@ -38,4 +48,21 @@ def main():
                        print event
 
 if __name__ == '__main__':
+    """
+       To test the PERF_RECORD_SWITCH record, pick a pid and replace
+       in the following line.
+
+       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 }
+
+       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)
     main()