view tests/test-issue1877.t @ 24461:05ccfe6763f1

osutil: use getdirentriesattr on OS X if possible This is a significant win for large repositories on OS X, especially with a cold cache. Unfortunately we need to keep the lstat-based implementation around for two reasons: - Not all filesystems support this call. - There's an edge case in which it's best to fall back to avoid a retry loop. More about this in the comments. The below tests are all performed on a Mac with an SSD running OS X 10.9, on a repository with over 200k files. The results are best of 5 with simulated best-effort conditions. The gains with a hot cache are pretty impressive: 'hg status' goes from 5.18 seconds to 3.79 seconds. However, a repository that large will probably already be using something like hgwatchman [1], which helps much more (for this repo, 'hg status' with hgwatchman is approximately 1 second). Where this really helps is when the cache is cold [2]: hg status goes from 31.0 seconds to 9.66. See http://lists.apple.com/archives/filesystem-dev/2014/Dec/msg00002.html for some more discussion about this function. This is based on a patch by Sean Farley <sean@farley.io>. [1] https://bitbucket.org/facebook/hgwatchman [2] There appears to be no easy way to clear the file cache (aka "vnodes") on OS X short of rebooting. purge(8) purportedly does that but in my testing had little effect. The workaround I came up with was to assume that vnode eviction was LRU, make sure the kern.maxvnodes sysctl is smaller than the size of the repository, then make sure we'd always miss the cache by running 'hg status' in another clone of the repository before running it in the test repository.
author Siddharth Agarwal <sid0@fb.com>
date Wed, 25 Mar 2015 15:55:31 -0700
parents ca275f7ec576
children 2fc86d92c4a9
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http://mercurial.selenic.com/bts/issue1877

  $ hg init a
  $ cd a
  $ echo a > a
  $ hg add a
  $ hg ci -m 'a'
  $ echo b > a
  $ hg ci -m'b'
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg book main
  $ hg book
   * main                      0:cb9a9f314b8b
  $ echo c > c
  $ hg add c
  $ hg ci -m'c'
  created new head
  $ hg book
   * main                      2:d36c0562f908
  $ hg heads
  changeset:   2:d36c0562f908
  bookmark:    main
  tag:         tip
  parent:      0:cb9a9f314b8b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     c
  
  changeset:   1:1e6c11564562
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  $ hg up 1e6c11564562
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (leaving bookmark main)
  $ hg merge main
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg book
     main                      2:d36c0562f908
  $ hg ci -m'merge'
  $ hg book
     main                      2:d36c0562f908

  $ cd ..