[RFC PATCH v2 3/3] trace-cruncher: perf example

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

Example python program for using trace-cruncher to collect performance
statistics of a given process.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 examples/perf_sampling.py | 53 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100755 examples/perf_sampling.py

diff --git a/examples/perf_sampling.py b/examples/perf_sampling.py
new file mode 100755
index 0000000..6219bff
--- /dev/null
+++ b/examples/perf_sampling.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+
+"""
+SPDX-License-Identifier: CC-BY-4.0
+
+Copyright 2022 VMware Inc, Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
+"""
+
+import sys
+import time
+import shutil
+
+import tracecruncher.perfpy as perf
+
+def SortKey(sample):
+    return sample.time()
+
+if __name__ == "__main__":
+    if len(sys.argv) < 2:
+        print('Usage: ', sys.argv[0], ' [PROCESS]')
+        sys.exit(1)
+
+    # Create perf sample object for the given process
+    if sys.argv[1].isdigit():
+        p = perf.sampler_instance(pid=int(sys.argv[1]), freq=99)
+    else:
+        file = shutil.which(sys.argv[1])
+        if file is None:
+            print('Cannot find ', sys.argv[1], ' in the system')
+            sys.exit(1)
+        p = perf.sampler_instance(command=file, argv=sys.argv[1:], freq=99)
+
+    print('Start collecting performance data, press ctrl+c  to stop')
+    # Start collecting performance traces
+    p.enable(wait=True)
+
+    # Get collected samples
+    samples = p.get_samples()
+    # Sort the list based on the timestamp
+    samples.sort(key=SortKey)
+    time = 0
+    ip_count = 0
+    for s in samples:
+        # Print PID, TID, time and trace depth of each sample
+        if time == 0:
+            time = s.time()
+        print("{0} {1} ({2}), +{3}:".format(s.ip(), s.tid(), s.tid_comm(), s.time() - time))
+        ips = s.stack()
+        ip_count += len(ips)
+        for ip in reversed(ips):
+            # Print stack trace of the sample
+            print("\t{0}".format(ip))
+    print("\nCollected {0} samples, {1} ip traces".format(len(samples), ip_count))
\ No newline at end of file
-- 
2.35.1