status: prefer relative paths in Rust code … when the repository root is under the current directory, so the kernel needs to traverse fewer directory in every call to `read_dir` or `symlink_metadata`. Better yet would be to use libc functions like `openat` and `fstatat` to remove such repeated traversals entirely, but the standard library does not provide APIs based on those. Maybe with a crate like https://crates.io/crates/openat instead? Benchmarks of `rhg status` show that this patch is neutral in some configurations, and makes the command up to ~20% faster in others. Below is semi-arbitrary subset of results. The four numeric columns are: time (in seconds) with this changeset’s parent, time with this changeset, time difference (negative is better), time ratio (less than 1 is better). ``` mercurial-dirstate-v1 | default-plain-clean.no-iu.pbr | 0.0061 -> 0.0059: -0.0002 (0.97) mercurial-dirstate-v2 | default-plain-clean.no-iu.pbr | 0.0029 -> 0.0028: -0.0001 (0.97) mozilla-dirstate-v1 | default-plain-clean.no-iu.pbr | 0.2110 -> 0.2102: -0.0007 (1.00) mozilla-dirstate-v2 | default-copies-clean.ignored.pbr | 0.0489 -> 0.0401: -0.0088 (0.82) mozilla-dirstate-v2 | default-copies-clean.no-iu.pbr | 0.0479 -> 0.0393: -0.0085 (0.82) mozilla-dirstate-v2 | default-copies-large.all.pbr | 0.1262 -> 0.1210: -0.0051 (0.96) mozilla-dirstate-v2 | default-copies-small.ignored-unknown.pbr | 0.1262 -> 0.1200: -0.0062 (0.95) mozilla-dirstate-v2 | default-copies-small.ignored.pbr | 0.0536 -> 0.0417: -0.0119 (0.78) mozilla-dirstate-v2 | default-copies-small.no-iu.pbr | 0.0482 -> 0.0393: -0.0089 (0.81) mozilla-dirstate-v2 | default-plain-clean.ignored.pbr | 0.0518 -> 0.0402: -0.0116 (0.78) mozilla-dirstate-v2 | default-plain-clean.no-iu.pbr | 0.0481 -> 0.0392: -0.0088 (0.82) mozilla-dirstate-v2 | default-plain-large.all.pbr | 0.1271 -> 0.1218: -0.0052 (0.96) mozilla-dirstate-v2 | default-plain-small.ignored-unknown.pbr | 0.1225 -> 0.1202: -0.0022 (0.98) mozilla-dirstate-v2 | default-plain-small.ignored.pbr | 0.0510 -> 0.0418: -0.0092 (0.82) mozilla-dirstate-v2 | default-plain-small.no-iu.pbr | 0.0480 -> 0.0394: -0.0086 (0.82) netbeans-dirstate-v1 | default-plain-clean.no-iu.pbr | 0.1442 -> 0.1422: -0.0020 (0.99) netbeans-dirstate-v2 | default-plain-clean.no-iu.pbr | 0.0325 -> 0.0282: -0.0043 (0.87) ``` Differential Revision: https://phab.mercurial-scm.org/D12175

     1

# bruterebase.py - brute force rebase testing

     2

#

     3

# Copyright 2017 Facebook, Inc.

     4

#

     5

# This software may be used and distributed according to the terms of the

     6

# GNU General Public License version 2 or any later version.

     7

     8

from __future__ import absolute_import

     9

    10

from mercurial import (

    11

    error,

    12

    registrar,

    13

    revsetlang,

    14

)

    15

    16

from hgext import rebase

    17

    18

try:

    19

    xrange

    20

except NameError:

    21

    xrange = range

    22

    23

cmdtable = {}

    24

command = registrar.command(cmdtable)

    25

    26

    27

@command(b'debugbruterebase')

    28

def debugbruterebase(ui, repo, source, dest):

    29

    """for every non-empty subset of source, run rebase -r subset -d dest

    30

    31

    Print one line summary for each subset. Assume obsstore is enabled.

    32

    """

    33

    srevs = list(repo.revs(source))

    34

    35

    with repo.wlock(), repo.lock():

    36

        repolen = len(repo)

    37

        cl = repo.changelog

    38

    39

        def getdesc(rev):

    40

            result = cl.changelogrevision(rev).description

    41

            if rev >= repolen:

    42

                result += b"'"

    43

            return result

    44

    45

        for i in xrange(1, 2 ** len(srevs)):

    46

            subset = [rev for j, rev in enumerate(srevs) if i & (1 << j) != 0]

    47

            spec = revsetlang.formatspec(b'%ld', subset)

    48

            tr = repo.transaction(b'rebase')

    49

            tr._report = lambda x: 0  # hide "transaction abort"

    50

    51

            with ui.silent():

    52

                try:

    53

                    rebase.rebase(ui, repo, dest=dest, rev=[spec])

    54

                except error.Abort as ex:

    55

                    summary = b'ABORT: %s' % ex.message

    56

                except Exception as ex:

    57

                    summary = b'CRASH: %s' % ex

    58

                else:

    59

                    # short summary about new nodes

    60

                    cl = repo.changelog

    61

                    descs = []

    62

                    for rev in xrange(repolen, len(repo)):

    63

                        desc = b'%s:' % getdesc(rev)

    64

                        for prev in cl.parentrevs(rev):

    65

                            if prev > -1:

    66

                                desc += getdesc(prev)

    67

                        descs.append(desc)

    68

                    descs.sort()

    69

                    summary = b' '.join(descs)

    70

            repo.vfs.tryunlink(b'rebasestate')

    71

    72

            subsetdesc = b''.join(getdesc(rev) for rev in subset)

    73

            ui.write(b'%s: %s\n' % (subsetdesc.rjust(len(srevs)), summary))

    74

            tr.abort()