stream-clone: disable gc for `_entries_walk` duration
The number of small container created turn Python in a gc-frenzy that seriously
impact performance.
This significantly boost performance. The following number comes from a large
private repository using perf::stream-locked-section:
base-line: 35.04 seconds
prev-change: 24.51 seconds (-30%)
this-change: 20.88 seconds (-40% from baseline; -15% from previous changes)
import io
import unittest
from mercurial import util
class CappedReaderTests(unittest.TestCase):
def testreadfull(self):
source = io.BytesIO(b'x' * 100)
reader = util.cappedreader(source, 10)
res = reader.read(10)
self.assertEqual(res, b'x' * 10)
self.assertEqual(source.tell(), 10)
source.seek(0)
reader = util.cappedreader(source, 15)
res = reader.read(16)
self.assertEqual(res, b'x' * 15)
self.assertEqual(source.tell(), 15)
source.seek(0)
reader = util.cappedreader(source, 100)
res = reader.read(100)
self.assertEqual(res, b'x' * 100)
self.assertEqual(source.tell(), 100)
source.seek(0)
reader = util.cappedreader(source, 50)
res = reader.read()
self.assertEqual(res, b'x' * 50)
self.assertEqual(source.tell(), 50)
source.seek(0)
def testreadnegative(self):
source = io.BytesIO(b'x' * 100)
reader = util.cappedreader(source, 20)
res = reader.read(-1)
self.assertEqual(res, b'x' * 20)
self.assertEqual(source.tell(), 20)
source.seek(0)
reader = util.cappedreader(source, 100)
res = reader.read(-1)
self.assertEqual(res, b'x' * 100)
self.assertEqual(source.tell(), 100)
source.seek(0)
def testreadmultiple(self):
source = io.BytesIO(b'x' * 100)
reader = util.cappedreader(source, 10)
for i in range(10):
res = reader.read(1)
self.assertEqual(res, b'x')
self.assertEqual(source.tell(), i + 1)
self.assertEqual(source.tell(), 10)
res = reader.read(1)
self.assertEqual(res, b'')
self.assertEqual(source.tell(), 10)
source.seek(0)
reader = util.cappedreader(source, 45)
for i in range(4):
res = reader.read(10)
self.assertEqual(res, b'x' * 10)
self.assertEqual(source.tell(), (i + 1) * 10)
res = reader.read(10)
self.assertEqual(res, b'x' * 5)
self.assertEqual(source.tell(), 45)
def readlimitpasteof(self):
source = io.BytesIO(b'x' * 100)
reader = util.cappedreader(source, 1024)
res = reader.read(1000)
self.assertEqual(res, b'x' * 100)
self.assertEqual(source.tell(), 100)
res = reader.read(1000)
self.assertEqual(res, b'')
self.assertEqual(source.tell(), 100)
if __name__ == '__main__':
import silenttestrunner
silenttestrunner.main(__name__)