diff options
| -rw-r--r-- | Lib/subprocess.py | 2 | ||||
| -rw-r--r-- | Misc/NEWS | 4 |
2 files changed, 5 insertions, 1 deletions
diff --git a/Lib/subprocess.py b/Lib/subprocess.py index 546a7a0fcd..78e4fcfc59 100644 --- a/Lib/subprocess.py +++ b/Lib/subprocess.py @@ -1654,7 +1654,7 @@ class Popen(object): if self._input_offset >= len(self._input): close_unregister_and_remove(fd) elif mode & select_POLLIN_POLLPRI: - data = os.read(fd, 4096) + data = os.read(fd, 32768) if not data: close_unregister_and_remove(fd) self._fd2output[fd].append(data) @@ -18,6 +18,10 @@ Core and Builtins Library ------- +- Issue #19929: Call os.read with 32768 within subprocess.Popen.communicate + rather than 4096 for efficiency. A microbenchmark shows Linux and OS X + both using ~50% less cpu time this way. + - Issue #19506: Use a memoryview to avoid a data copy when piping data to stdin within subprocess.Popen.communicate. 5-10% less cpu usage. |