heftig created this revision. Herald added subscribers: mercurial-devel, mjpieters. Herald added a reviewer: hg-reviewers.
REVISION SUMMARY My previous fix (D8051 <https://phab.mercurial-scm.org/D8051>, which added Python's built-in buffering to the pickle stream) has the problem that the selector will ignore the buffer. When multiple pickled objects are read from the pipe into the buffer at once, only one object will be loaded. This can repeat until the buffer is full and delays the processing of completed items until the worker exits, at which point the pipe is always considered readable and all remaining items are processed. This changeset reverts D8051 <https://phab.mercurial-scm.org/D8051>, removing the buffer again. Instead, on Python 3 only, we use a wrapper to modify the "read" provided to the Unpickler to behave more like a buffered read. We never read more bytes from the pipe than the Unpickler requests, so the selector behaves as expected. Also add a test case for "pickle data was truncated" issue. https://phab.mercurial-scm.org/D8051#119193 REPOSITORY rHG Mercurial BRANCH stable REVISION DETAIL https://phab.mercurial-scm.org/D8076 AFFECTED FILES mercurial/worker.py tests/test-worker.t CHANGE DETAILS diff --git a/tests/test-worker.t b/tests/test-worker.t --- a/tests/test-worker.t +++ b/tests/test-worker.t @@ -131,4 +131,35 @@ abort: known exception [255] +Do not crash on partially read result + + $ cat > $TESTTMP/detecttruncated.py <<EOF + > from __future__ import absolute_import + > import os + > import sys + > import time + > sys.unraisablehook = lambda x: None + > oldwrite = os.write + > def splitwrite(fd, string): + > ret = oldwrite(fd, string[:9]) + > if ret == 9: + > time.sleep(0.1) + > ret += oldwrite(fd, string[9:]) + > return ret + > os.write = splitwrite + > EOF + + $ hg --config "extensions.t=$abspath" --config worker.numcpus=8 --config \ + > "extensions.d=$TESTTMP/detecttruncated.py" test 100000.0 + start + run + run + run + run + run + run + run + run + done + #endif diff --git a/mercurial/worker.py b/mercurial/worker.py --- a/mercurial/worker.py +++ b/mercurial/worker.py @@ -65,6 +65,41 @@ return min(max(countcpus(), 4), 32) +if pycompat.ispy3: + + class _blockingreader(object): + def __init__(self, wrapped): + self._wrapped = wrapped + + def __getattr__(self, attr): + return getattr(self._wrapped, attr) + + # issue multiple reads until size is fulfilled + def read(self, size=-1): + if size < 0: + return self._wrapped.readall() + + buf = bytearray(size) + view = memoryview(buf) + pos = 0 + + while pos < size: + ret = self._wrapped.readinto(view[pos:]) + if not ret: + break + pos += ret + + del view + del buf[pos:] + return buf + + +else: + + def _blockingreader(wrapped): + return wrapped + + if pycompat.isposix or pycompat.iswindows: _STARTUP_COST = 0.01 # The Windows worker is thread based. If tasks are CPU bound, threads @@ -226,7 +261,7 @@ selector = selectors.DefaultSelector() for rfd, wfd in pipes: os.close(wfd) - selector.register(os.fdopen(rfd, 'rb'), selectors.EVENT_READ) + selector.register(os.fdopen(rfd, 'rb', 0), selectors.EVENT_READ) def cleanup(): signal.signal(signal.SIGINT, oldhandler) @@ -240,7 +275,7 @@ while openpipes > 0: for key, events in selector.select(): try: - res = util.pickle.load(key.fileobj) + res = util.pickle.load(_blockingreader(key.fileobj)) if hasretval and res[0]: retval.update(res[1]) else: To: heftig, #hg-reviewers Cc: mjpieters, mercurial-devel _______________________________________________ Mercurial-devel mailing list Mercurial-devel@mercurial-scm.org https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel
