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
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ hg commit -qAm x
$ mkdir dir
$ echo y > dir/y
$ hg commit -qAm y
$ cd ..
Shallow clone from full
$ hgcloneshallow ssh://user@dummy/master shallow --noupdate
streaming all changes
2 files to transfer, 473 bytes of data
transferred 473 bytes in * seconds (*/sec) (glob)
searching for changes
no changes found
$ cd shallow
$ hg debugrequires
dotencode
dirstate-v2 (dirstate-v2 !)
exp-remotefilelog-repo-req-1
fncache
generaldelta
persistent-nodemap (rust !)
revlog-compression-zstd (zstd !)
revlogv1
share-safe
sparserevlog
store
$ hg update
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
Log on a file without -f
$ hg log dir/y
warning: file log can be slow on large repos - use -f to speed it up
changeset: 1:2e73264fab97
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: y
Log on a file with -f
$ hg log -f dir/y
changeset: 1:2e73264fab97
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: y
Log on a file with kind in path
$ hg log -r "filelog('path:dir/y')"
changeset: 1:2e73264fab97
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: y
Log on multiple files with -f
$ hg log -f dir/y x
changeset: 1:2e73264fab97
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: y
changeset: 0:b292c1e3311f
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: x
Log on a directory
$ hg log dir
changeset: 1:2e73264fab97
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: y
Log on a file from inside a directory
$ cd dir
$ hg log y
warning: file log can be slow on large repos - use -f to speed it up
changeset: 1:2e73264fab97
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: y
Log on a file via -fr
$ cd ..
$ hg log -fr tip dir/ --template '{rev}\n'
1
Trace renames
$ hg mv x z
$ hg commit -m move
$ hg log -f z -T '{desc} {file_copies}\n' -G
@ move z (x)
:
o x
Verify remotefilelog handles rename metadata stripping when comparing file sizes
$ hg debugrebuilddirstate
$ hg status