Thread (5 messages) 5 messages, 2 authors, 2024-06-17

Re: [PATCH 2/2] tools/perf: Fix parallel-perf python script to replace new python syntax ":=" usage

From: Adrian Hunter <adrian.hunter@intel.com>
Date: 2024-06-16 15:03:33
Also in: linux-perf-users, lkml

On 14/06/24 20:27, Athira Rajeev wrote:
perf test "perf script tests" fails as below in systems
with python 3.6

	File "/home/athira/linux/tools/perf/tests/shell/../../scripts/python/parallel-perf.py", line 442
	if line := p.stdout.readline():
             ^
	SyntaxError: invalid syntax
	--- Cleaning up ---
	---- end(-1) ----
	92: perf script tests: FAILED!

This happens because ":=" is a new syntax that assigns values
to variables as part of a larger expression. This is introduced
from python 3.8 and hence fails in setup with python 3.6
According to below python 3.6 is end-of-life

	https://devguide.python.org/versions/

What was still using python 3.6?
Address this by splitting the large expression and check the
value in two steps:
Previous line: if line := p.stdout.readline():
Current change:
	line = p.stdout.readline()
	if line:

With patch

	./perf test "perf script tests"
	 93: perf script tests:  Ok

Signed-off-by: Athira Rajeev <redacted>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
quoted hunk ↗ jump to hunk
---
 tools/perf/scripts/python/parallel-perf.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/perf/scripts/python/parallel-perf.py b/tools/perf/scripts/python/parallel-perf.py
index 21f32ec5ed46..be85fd7f6632 100755
--- a/tools/perf/scripts/python/parallel-perf.py
+++ b/tools/perf/scripts/python/parallel-perf.py
@@ -439,7 +439,8 @@ def ProcessCommandOutputLines(cmd, per_cpu, fn, *x):
 	pat = re.compile(r"\s*\[[0-9]+\]")
 	p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
 	while True:
-		if line := p.stdout.readline():
+		line = p.stdout.readline()
+		if line:
 			line = line.decode("utf-8")
 			if pat.match(line):
 				line = line.split()
  
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