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
#if no-extraextensions
$ hg debugextensions
#endif
$ debugpath=`pwd`/extwithoutinfos.py
$ cat > extwithoutinfos.py <<EOF
> EOF
$ cat > extwithinfos.py <<EOF
> testedwith = b'3.0 3.1 3.2.1'
> buglink = b'https://example.org/bts'
> EOF
$ cat >> $HGRCPATH <<EOF
> [extensions]
> histedit=
> patchbomb=
> rebase=
> mq=
> ext1 = $debugpath
> ext2 = `pwd`/extwithinfos.py
> EOF
$ for extension in $HGTESTEXTRAEXTENSIONS; do
> echo "$extension=!" >> $HGRCPATH
> done
$ hg debugextensions
ext1 (untested!)
ext2 (3.2.1!)
histedit
mq
patchbomb
rebase
$ hg debugextensions -v
ext1
location: */extwithoutinfos.py* (glob)
bundled: no
ext2
location: */extwithinfos.py* (glob)
bundled: no
tested with: 3.0 3.1 3.2.1
bug reporting: https://example.org/bts
histedit
location: */hgext/histedit.py* (glob)
bundled: yes
mq
location: */hgext/mq.py* (glob)
bundled: yes
patchbomb
location: */hgext/patchbomb.py* (glob)
bundled: yes
rebase
location: */hgext/rebase.py* (glob)
bundled: yes
$ hg debugextensions -Tjson | sed 's|\\\\|/|g'
[
{
"buglink": "",
"bundled": false,
"name": "ext1",
"source": "*/extwithoutinfos.py*", (glob)
"testedwith": []
},
{
"buglink": "https://example.org/bts",
"bundled": false,
"name": "ext2",
"source": "*/extwithinfos.py*", (glob)
"testedwith": ["3.0", "3.1", "3.2.1"]
},
{
"buglink": "",
"bundled": true,
"name": "histedit",
"source": "*/hgext/histedit.py*", (glob)
"testedwith": []
},
{
"buglink": "",
"bundled": true,
"name": "mq",
"source": "*/hgext/mq.py*", (glob)
"testedwith": []
},
{
"buglink": "",
"bundled": true,
"name": "patchbomb",
"source": "*/hgext/patchbomb.py*", (glob)
"testedwith": []
},
{
"buglink": "",
"bundled": true,
"name": "rebase",
"source": "*/hgext/rebase.py*", (glob)
"testedwith": []
}
]
$ hg debugextensions -T '{ifcontains("3.1", testedwith, "{name}\n")}'
ext2
$ hg debugextensions \
> -T '{ifcontains("3.2", testedwith, "no substring match: {name}\n")}'