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

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Corrupt an hg repo with two pulls.

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create one repo with a long history

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  $ hg init source1

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  $ cd source1

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  $ touch foo

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  $ hg add foo

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  $ for i in 1 2 3 4 5 6 7 8 9 10; do

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  >     echo $i >> foo

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  >     hg ci -m $i

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  > done

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  $ cd ..

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create one repo with a shorter history

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  $ hg clone -r 0 source1 source2

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  adding changesets

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  adding manifests

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  adding file changes

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  added 1 changesets with 1 changes to 1 files

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  new changesets 495a0ec48aaf

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  updating to branch default

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

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  $ cd source2

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  $ echo a >> foo

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  $ hg ci -m a

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  $ cd ..

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create a third repo to pull both other repos into it

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  $ hg init corrupted

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  $ cd corrupted

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use a hook to make the second pull start while the first one is still running

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  $ echo '[hooks]' >> .hg/hgrc

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  $ echo 'prechangegroup = sleep 5' >> .hg/hgrc

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start a pull...

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  $ hg pull ../source1 > pull.out 2>&1 &

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... and start another pull before the first one has finished

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  $ sleep 1

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  $ hg pull ../source2 2>/dev/null

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  pulling from ../source2

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  searching for changes

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  adding changesets

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  adding manifests

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  adding file changes

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  added 1 changesets with 1 changes to 1 files (+1 heads)

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  new changesets ca3c05af513e

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  (run 'hg heads' to see heads, 'hg merge' to merge)

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  $ cat pull.out

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  pulling from ../source1

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  requesting all changes

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  adding changesets

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  adding manifests

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  adding file changes

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  added 10 changesets with 10 changes to 1 files

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  new changesets 495a0ec48aaf:1e7b6c812ca8

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  (run 'hg update' to get a working copy)

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see the result

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  $ wait

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  $ hg verify

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  checking changesets

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  checking manifests

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  crosschecking files in changesets and manifests

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  checking files

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  checked 11 changesets with 11 changes to 1 files

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  $ cd ..