worker: ability to disable thread unsafe tasks
The worker on Windows is implemented using a thread pool. If worker
tasks are not thread safe, badness can occur. In addition, if tasks
are executing CPU bound code and holding onto the GIL, there will be
non-substantial overhead in Python context switching between active
threads. This can result in significant slowdowns of tasks.
This commit teaches the code for determining whether to use a worker
to take thread safety into account. Effectively, thread unsafe tasks
don't use the thread-based worker on Windows.
Differential Revision: https://phab.mercurial-scm.org/D3962
#!/usr/bin/env python
# Undump a dump from dumprevlog
# $ hg init
# $ undumprevlog < repo.dump
from __future__ import absolute_import, print_function
import sys
from mercurial import (
node,
revlog,
transaction,
vfs as vfsmod,
)
from mercurial.utils import (
procutil,
)
for fp in (sys.stdin, sys.stdout, sys.stderr):
procutil.setbinary(fp)
opener = vfsmod.vfs('.', False)
tr = transaction.transaction(sys.stderr.write, opener, {'store': opener},
"undump.journal")
while True:
l = sys.stdin.readline()
if not l:
break
if l.startswith("file:"):
f = l[6:-1]
r = revlog.revlog(opener, f)
print(f)
elif l.startswith("node:"):
n = node.bin(l[6:-1])
elif l.startswith("linkrev:"):
lr = int(l[9:-1])
elif l.startswith("parents:"):
p = l[9:-1].split()
p1 = node.bin(p[0])
p2 = node.bin(p[1])
elif l.startswith("length:"):
length = int(l[8:-1])
sys.stdin.readline() # start marker
d = sys.stdin.read(length)
sys.stdin.readline() # end marker
r.addrevision(d, tr, lr, p1, p2)
tr.close()