view mercurial/scmposix.py @ 51592:24844407fa0d

perf: clear vfs audit_cache before each run

When generating a stream clone, we spend a large amount of time auditing path.
Before this changes, the first run was warming the vfs cache for the other
runs, leading to a large runtime difference and a "faulty" reported timing for
the operation.

We now clear this important cache between run to get a more realistic timing.

Below are some example of median time change when clearing these cases. The
maximum time for a run did not changed significantly.

### data-env-vars.name             = mozilla-central-2018-08-01-zstd-sparse-revlog
  # benchmark.name                = hg.perf.exchange.stream.generate
  # bin-env-vars.hg.flavor         = default
  # bin-env-vars.hg.py-re2-module  = default
  # benchmark.variants.version    = latest
no-clearing:    17.289905
cache-clearing: 21.587965  (+24.86%, +4.30)
 ## data-env-vars.name             = mozilla-central-2024-03-22-zstd-sparse-revlog
no-clearing:    32.670748
cache-clearing: 40.467095  (+23.86%, +7.80)
 ## data-env-vars.name             = mozilla-try-2019-02-18-zstd-sparse-revlog
no-clearing:    37.838858
cache-clearing: 46.072749  (+21.76%, +8.23)
 ## data-env-vars.name             = mozilla-unified-2024-03-22-zstd-sparse-revlog
no-clearing:    32.969395
cache-clearing: 39.646209  (+20.25%, +6.68)

In addition, this significantly reduce the timing difference between the
performance command, from the perf extensions and a `real `hg bundle` call
producing a stream bundle. Some significant differences remain especially on
the "mozilla-try" repositories, but they are now smaller.

Note that some of that difference will actually not be
attributable to the stream generation (like maybe phases or branch map
computation).

Below are some benchmarks done on a currently draft changeset fixing some
unrelated slowness in `hg bundle` (34a78972af409d1ff37c29e60f6ca811ad1a457d)

### data-env-vars.name             = mozilla-central-2018-08-01-zstd-sparse-revlog
  # bin-env-vars.hg.flavor         = default
  # bin-env-vars.hg.py-re2-module  = default
hg.perf.exchange.stream.generate:  21.587965
hg.command.bundle:                 24.301799  (+12.57%, +2.71)
 ## data-env-vars.name             = mozilla-central-2024-03-22-zstd-sparse-revlog
hg.perf.exchange.stream.generate:  40.467095
hg.command.bundle:                 44.831317  (+10.78%, +4.36)
 ## data-env-vars.name             = mozilla-unified-2024-03-22-zstd-sparse-revlog
hg.perf.exchange.stream.generate:  39.646209
hg.command.bundle:                 45.395258  (+14.50%, +5.75)
 ## data-env-vars.name             = mozilla-try-2019-02-18-zstd-sparse-revlog
hg.perf.exchange.stream.generate:  46.072749
hg.command.bundle:                 55.882608  (+21.29%, +9.81)
 ## data-env-vars.name             = mozilla-try-2023-03-22-zlib-general-delta
hg.perf.exchange.stream.generate: 334.716708
hg.command.bundle:                377.856767  (+12.89%, +43.14)
 ## data-env-vars.name             = mozilla-try-2023-03-22-zstd-sparse-revlog
hg.perf.exchange.stream.generate: 302.972301
hg.command.bundle:                326.098755  (+7.63%, +23.13)

import array
import errno
import fcntl
import os
import sys
import typing

from typing import (
    List,
    Tuple,
)

from . import (
    encoding,
    pycompat,
    util,
)

if typing.TYPE_CHECKING:
    from . import ui as uimod

# BSD 'more' escapes ANSI color sequences by default. This can be disabled by
# $MORE variable, but there's no compatible option with Linux 'more'. Given
# OS X is widely used and most modern Unix systems would have 'less', setting
# 'less' as the default seems reasonable.
fallbackpager = b'less'


def _rcfiles(path: bytes) -> List[bytes]:
    rcs = [os.path.join(path, b'hgrc')]
    rcdir = os.path.join(path, b'hgrc.d')
    try:
        rcs.extend(
            [
                os.path.join(rcdir, f)
                for f, kind in sorted(util.listdir(rcdir))
                if f.endswith(b".rc")
            ]
        )
    except OSError:
        pass
    return rcs


def systemrcpath() -> List[bytes]:
    path = []
    if pycompat.sysplatform == b'plan9':
        root = b'lib/mercurial'
    else:
        root = b'etc/mercurial'
    # old mod_python does not set sys.argv
    if len(getattr(sys, 'argv', [])) > 0:
        p = os.path.dirname(os.path.dirname(pycompat.sysargv[0]))
        if p != b'/':
            path.extend(_rcfiles(os.path.join(p, root)))
    path.extend(_rcfiles(b'/' + root))
    return path


def userrcpath() -> List[bytes]:
    if pycompat.sysplatform == b'plan9':
        return [encoding.environ[b'home'] + b'/lib/hgrc']
    elif pycompat.isdarwin:
        return [os.path.expanduser(b'~/.hgrc')]
    else:
        confighome = encoding.environ.get(b'XDG_CONFIG_HOME')
        if confighome is None or not os.path.isabs(confighome):
            confighome = os.path.expanduser(b'~/.config')

        return [
            os.path.expanduser(b'~/.hgrc'),
            os.path.join(confighome, b'hg', b'hgrc'),
        ]


def termsize(ui: "uimod.ui") -> Tuple[int, int]:
    try:
        import termios

        TIOCGWINSZ = termios.TIOCGWINSZ  # unavailable on IRIX (issue3449)
    except (AttributeError, ImportError):
        return 80, 24

    for dev in (ui.ferr, ui.fout, ui.fin):
        try:
            try:
                fd = dev.fileno()
            except AttributeError:
                continue
            if not os.isatty(fd):
                continue
            arri = fcntl.ioctl(fd, TIOCGWINSZ, b'\0' * 8)
            height, width = array.array('h', arri)[:2]
            if width > 0 and height > 0:
                return width, height
        except ValueError:
            pass
        except IOError as e:
            if e.errno == errno.EINVAL:
                pass
            else:
                raise
    return 80, 24