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

  $ hg init

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  $ echo "added file1" > file1

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  $ echo "another line of text" >> file1

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  $ echo "added file2" > file2

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  $ hg add file1 file2

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  $ hg commit -m "added file1 and file2"

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  $ echo "changed file1" >> file1

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  $ hg commit -m "changed file1"

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  $ hg -q log

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  1:dfab7f3c2efb

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  0:c3fa057dd86f

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  $ hg id

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  dfab7f3c2efb tip

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  $ hg update -C 0

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  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

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  $ hg id

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  c3fa057dd86f

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  $ echo "changed file1" >> file1

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  $ hg id

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  c3fa057dd86f+

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  $ hg revert --no-backup --all

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  reverting file1

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  $ hg diff

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  $ hg status

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  $ hg id

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  c3fa057dd86f

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  $ hg update

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  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

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  $ hg diff

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  $ hg status

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  $ hg id

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  dfab7f3c2efb tip

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  $ hg update -C 0

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  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

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  $ echo "changed file1 different" >> file1

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  $ hg update

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  merging file1

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  warning: conflicts while merging file1! (edit, then use 'hg resolve --mark')

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  0 files updated, 0 files merged, 0 files removed, 1 files unresolved

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  use 'hg resolve' to retry unresolved file merges

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  [1]

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  $ hg diff --nodates

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  diff -r dfab7f3c2efb file1

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  --- a/file1

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  +++ b/file1

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  @@ -1,3 +1,7 @@

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   added file1

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   another line of text

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  +<<<<<<< working copy: c3fa057dd86f - test: added file1 and file2

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  +changed file1 different

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  +=======

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   changed file1

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  +>>>>>>> destination:  dfab7f3c2efb - test: changed file1

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  $ hg status

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  M file1

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  ? file1.orig

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  $ hg id

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  dfab7f3c2efb+ tip

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  $ hg revert --no-backup --all

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  reverting file1

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  $ hg diff

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  $ hg status

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  ? file1.orig

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  $ hg id

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  dfab7f3c2efb tip

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  $ hg revert -r tip --no-backup --all

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  $ hg diff

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  $ hg status

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  ? file1.orig

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  $ hg id

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  dfab7f3c2efb tip

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  $ hg update -C

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  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

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  $ hg diff

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  $ hg status

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  ? file1.orig

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  $ hg id

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  dfab7f3c2efb tip

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