perf python: Allow KeyboardInterrupt to propagate in LiveSession

LiveSession.run() synchronously blocks while polling evlist for events.
When running interactive tools or scripts from the terminal,
KeyboardInterrupt exceptions raised via Ctrl-C must propagate so the
caller can break out of the polling loop.

Previously, LiveSession caught KeyboardInterrupt with an empty pass
statement, swallowing the exception and preventing calling scripts from
detecting the interrupt cleanly. Remove the empty handler so calling
scripts receive KeyboardInterrupt and can perform clean teardown.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/tools/perf/python/perf_live.py b/tools/perf/python/perf_live.py
index 616b5f657463..99e73d58a96f 100755
--- a/tools/perf/python/perf_live.py
+++ b/tools/perf/python/perf_live.py
@@ -33,10 +33,16 @@ class LiveSession:
                 # Poll for events with 100ms timeout
                 try:
                     self.evlist.poll(100)
+                # CPython's PyErr_SetFromErrno() invokes PyErr_CheckSignals() on
+                # EINTR, converting SIGINT into KeyboardInterrupt, which inherits
+                # from BaseException rather than InterruptedError/OSError, so
+                # Ctrl-C exits the loop and triggers finally: self.evlist.close()
+                # while non-fatal signals retry poll().
                 except InterruptedError:
                     continue
                 for cpu in self.cpus:
-                    for _ in range(1000): # Limit to 1000 events per CPU per poll to prevent starvation
+                    # Limit to 1000 events per CPU per poll to prevent starvation
+                    for _ in range(1000):
                         try:
                             event = self.evlist.read_on_cpu(cpu)
                         except TypeError as e:
@@ -53,7 +59,5 @@ class LiveSession:
 
                         if event.type == perf.RECORD_SAMPLE:
                             self.sample_callback(event)
-        except KeyboardInterrupt:
-            pass
         finally:
             self.evlist.close()