exchange: send bundle2 stream clones uncompressed
Stream clones don't compress well. And compression undermines
a point of stream clones which is to trade significant CPU
reductions by increasing size.
Building upon our introduction of metadata to communicate bundle
information back to callers of exchange.getbundlechunks(), we add
an attribute to the bundler that communicates whether the bundle is
best left uncompressed. We return this attribute as part of the bundle
metadata. And the wire protocol honors it when determining whether
to compress the wire protocol response.
The added test demonstrates that the raw result from the wire
protocol is not compressed. It also demonstrates that the server
will serve stream responses when the feature isn't enabled. We'll
address that in another commit.
The effect of this change is that server-side CPU usage for bundle2
stream clones is significantly reduced by removing zstd compression.
For the mozilla-unified repository:
before: 37.69 user 8.01 system
after: 27.38 user 7.34 system
Assuming things are CPU bound, that ~10s reduction would translate to
faster clones on the client. zstd can decompress at >1 GB/s. So the
overhead from decompression on the client is small in the grand scheme
of things. But if zlib compression were being used, the overhead would
be much greater.
Differential Revision: https://phab.mercurial-scm.org/D1926
#!/usr/bin/env python
#
# checkseclevel - checking section title levels in each online help document
from __future__ import absolute_import
import optparse
import os
import sys
# import from the live mercurial repo
os.environ['HGMODULEPOLICY'] = 'py'
sys.path.insert(0, "..")
from mercurial import demandimport; demandimport.enable()
from mercurial import (
commands,
extensions,
help,
minirst,
ui as uimod,
)
table = commands.table
helptable = help.helptable
level2mark = [b'"', b'=', b'-', b'.', b'#']
reservedmarks = [b'"']
mark2level = {}
for m, l in zip(level2mark, range(len(level2mark))):
if m not in reservedmarks:
mark2level[m] = l
initlevel_topic = 0
initlevel_cmd = 1
initlevel_ext = 1
initlevel_ext_cmd = 3
def showavailables(ui, initlevel):
avail = (' available marks and order of them in this help: %s\n') % (
', '.join(['%r' % (m * 4) for m in level2mark[initlevel + 1:]]))
ui.warn(avail.encode('utf-8'))
def checkseclevel(ui, doc, name, initlevel):
ui.note(('checking "%s"\n') % name)
if not isinstance(doc, bytes):
doc = doc.encode('utf-8')
blocks, pruned = minirst.parse(doc, 0, ['verbose'])
errorcnt = 0
curlevel = initlevel
for block in blocks:
if block[b'type'] != b'section':
continue
mark = block[b'underline']
title = block[b'lines'][0]
if (mark not in mark2level) or (mark2level[mark] <= initlevel):
ui.warn((('invalid section mark %r for "%s" of %s\n') %
(mark * 4, title, name)).encode('utf-8'))
showavailables(ui, initlevel)
errorcnt += 1
continue
nextlevel = mark2level[mark]
if curlevel < nextlevel and curlevel + 1 != nextlevel:
ui.warn(('gap of section level at "%s" of %s\n') %
(title, name))
showavailables(ui, initlevel)
errorcnt += 1
continue
ui.note(('appropriate section level for "%s %s"\n') %
(mark * (nextlevel * 2), title))
curlevel = nextlevel
return errorcnt
def checkcmdtable(ui, cmdtable, namefmt, initlevel):
errorcnt = 0
for k, entry in cmdtable.items():
name = k.split(b"|")[0].lstrip(b"^")
if not entry[0].__doc__:
ui.note(('skip checking %s: no help document\n') %
(namefmt % name))
continue
errorcnt += checkseclevel(ui, entry[0].__doc__,
namefmt % name,
initlevel)
return errorcnt
def checkhghelps(ui):
errorcnt = 0
for names, sec, doc in helptable:
if callable(doc):
doc = doc(ui)
errorcnt += checkseclevel(ui, doc,
'%s help topic' % names[0],
initlevel_topic)
errorcnt += checkcmdtable(ui, table, '%s command', initlevel_cmd)
for name in sorted(list(extensions.enabled()) +
list(extensions.disabled())):
mod = extensions.load(ui, name, None)
if not mod.__doc__:
ui.note(('skip checking %s extension: no help document\n') % name)
continue
errorcnt += checkseclevel(ui, mod.__doc__,
'%s extension' % name,
initlevel_ext)
cmdtable = getattr(mod, 'cmdtable', None)
if cmdtable:
errorcnt += checkcmdtable(ui, cmdtable,
'%%s command of %s extension' % name,
initlevel_ext_cmd)
return errorcnt
def checkfile(ui, filename, initlevel):
if filename == '-':
filename = 'stdin'
doc = sys.stdin.read()
else:
with open(filename) as fp:
doc = fp.read()
ui.note(('checking input from %s with initlevel %d\n') %
(filename, initlevel))
return checkseclevel(ui, doc, 'input from %s' % filename, initlevel)
def main():
optparser = optparse.OptionParser("""%prog [options]
This checks all help documents of Mercurial (topics, commands,
extensions and commands of them), if no file is specified by --file
option.
""")
optparser.add_option("-v", "--verbose",
help="enable additional output",
action="store_true")
optparser.add_option("-d", "--debug",
help="debug mode",
action="store_true")
optparser.add_option("-f", "--file",
help="filename to read in (or '-' for stdin)",
action="store", default="")
optparser.add_option("-t", "--topic",
help="parse file as help topic",
action="store_const", dest="initlevel", const=0)
optparser.add_option("-c", "--command",
help="parse file as help of core command",
action="store_const", dest="initlevel", const=1)
optparser.add_option("-e", "--extension",
help="parse file as help of extension",
action="store_const", dest="initlevel", const=1)
optparser.add_option("-C", "--extension-command",
help="parse file as help of extension command",
action="store_const", dest="initlevel", const=3)
optparser.add_option("-l", "--initlevel",
help="set initial section level manually",
action="store", type="int", default=0)
(options, args) = optparser.parse_args()
ui = uimod.ui.load()
ui.setconfig('ui', 'verbose', options.verbose, '--verbose')
ui.setconfig('ui', 'debug', options.debug, '--debug')
if options.file:
if checkfile(ui, options.file, options.initlevel):
sys.exit(1)
else:
if checkhghelps(ui):
sys.exit(1)
if __name__ == "__main__":
main()