CONTRIBUTING

treemanifest: use visitchildrenset when doing a walk

For this series, starting at 'introduce lazy loading of subdirs' and ending with
this commit, we get the following timing numbers, using roughly the same
methodology and setup that we did in an earlier commit.

"before" is 6268fed3.

    diff --git:
    repo  | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
    ------+---+---+------------------------+-----------------------+------------
    m-u   |   |   | 1.585 s +-  0.034 s    | 1.574 s +-  0.045 s   |  99.3%
    m-u   |   | x | 1.591 s +-  0.024 s    | 1.601 s +-  0.034 s   | 100.6%
    m-u   | x |   | 1.579 s +-  0.032 s    | 1.603 s +-  0.029 s   | 101.5%
    m-u   | x | x | 109.8 ms +-   2.1 ms   | 108.8 ms +-   2.2 ms  |  99.1%
    l-d-r |   |   | 234.6 ms +-   5.1 ms   | 240.1 ms +-   7.9 ms  | 102.3%
    l-d-r |   | x | 238.3 ms +-   8.1 ms   | 232.2 ms +-   6.3 ms  |  97.4%
    l-d-r | x |   | 120.0 ms +-   2.7 ms   | 119.6 ms +-   2.1 ms  |  99.7%
    l-d-r | x | x | 120.2 ms +-   1.6 ms   | 119.1 ms +-   1.6 ms  |  99.1%

    diff -c . --git:
    repo  | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
    ------+---+---+------------------------+-----------------------+------------
    m-u   |   |   | 356.9 ms +-   5.6 ms   | 355.9 ms +-   5.6 ms  |  99.7%
    m-u   |   | x | 209.1 ms +-   3.3 ms   | 205.8 ms +-   2.6 ms  |  98.4%
    m-u   | x |   | 418.3 ms +-  14.0 ms   | 350.8 ms +-   7.7 ms  |  83.9% <--
    m-u   | x | x | 168.3 ms +-   1.5 ms   | 168.1 ms +-   2.7 ms  |  99.9%
    l-d-r |   |   | 100.5 ms +-   2.1 ms   | 99.1 ms +-   1.6 ms   |  98.6%
    l-d-r |   | x | 5.672 s +-  0.133 s    | 4.335 s +-  0.051 s   |  76.4% <--
    l-d-r | x |   | 102.8 ms +-   2.8 ms   | 100.4 ms +-   1.7 ms  |  97.7%
    l-d-r | x | x | 1.025 s +-  0.028 s    | 875.9 ms +-  12.1 ms  |  85.5% <--

    rebase -r . --keep -d .^^:
    repo  | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
    ------+---+---+------------------------+-----------------------+------------
    m-u   |   |   | 6.654 s +-  0.137 s    | 6.718 s +-  0.046 s   | 101.0%
    m-u   |   | x | 6.672 s +-  0.104 s    | 6.716 s +-  0.143 s   | 100.7%
    m-u   | x |   | 6.661 s +-  0.072 s    | 6.658 s +-  0.066 s   | 100.0%
    m-u   | x | x | 696.0 ms +-  49.0 ms   | 696.2 ms +-  54.8 ms  | 100.0%
    l-d-r |   |   | 789.1 ms +-  12.5 ms   | 793.5 ms +-  17.3 ms  | 100.6%
    l-d-r |   | x | 7.621 s +-  0.194 s    | 7.144 s +-  0.116 s   |  93.7% <--
    l-d-r | x |   | 335.4 ms +-   9.7 ms   | 339.6 ms +-  10.8 ms  | 101.3%
    l-d-r | x | x | 6.315 s +-  0.085 s    | 5.633 s +-  0.105 s   |  89.2% <--

    status --change . --copies:
    repo  | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
    ------+---+---+------------------------+-----------------------+------------
    m-u   |   |   | 331.2 ms +-   7.0 ms   | 335.1 ms +-   6.5 ms  | 101.2%
    m-u   |   | x | 184.0 ms +-   3.8 ms   | 183.1 ms +-   3.4 ms  |  99.5%
    m-u   | x |   | 330.5 ms +-   7.2 ms   | 332.7 ms +-   6.9 ms  | 100.7%
    m-u   | x | x | 148.7 ms +-   3.5 ms   | 147.5 ms +-   2.2 ms  |  99.2%
    l-d-r |   |   | 97.3 ms +-   1.3 ms    | 98.2 ms +-   2.5 ms   | 100.9%
    l-d-r |   | x | 5.196 s +-  0.030 s    | 4.281 s +-  0.025 s   |  82.4% <--
    l-d-r | x |   | 101.4 ms +-   3.1 ms   | 100.9 ms +-   1.8 ms  |  99.5%
    l-d-r | x | x | 1.015 s +-  0.018 s    | 861.2 ms +-  11.2 ms  |  84.8% <--

    status --copies:
    repo  | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
    ------+---+---+------------------------+-----------------------+------------
    m-u   |   |   | 2.356 s +-  0.032 s    | 2.369 s +-  0.027 s   | 100.6%
    m-u   |   | x | 2.371 s +-  0.041 s    | 2.385 s +-  0.028 s   | 100.6%
    m-u   | x |   | 2.366 s +-  0.036 s    | 2.379 s +-  0.030 s   | 100.5%
    m-u   | x | x | 121.8 ms +-   3.8 ms   | 121.1 ms +-   2.7 ms  |  99.4%
    l-d-r |   |   | 726.2 ms +-  12.9 ms   | 723.1 ms +-  12.7 ms  |  99.6%
    l-d-r |   | x | 738.7 ms +-  11.2 ms   | 741.3 ms +-  11.1 ms  | 100.4%
    l-d-r | x |   | 215.9 ms +-   3.6 ms   | 214.7 ms +-   5.9 ms  |  99.4%
    l-d-r | x | x | 213.1 ms +-   2.5 ms   | 212.8 ms +-   4.5 ms  |  99.9%

    update $rev^; ~/src/hg/hg{hg}/hg update $rev:
    repo  | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
    ------+---+---+------------------------+-----------------------+------------
    m-u   |   |   | 3.922 s +-  0.045 s    | 3.937 s +-  0.034 s   | 100.4%
    m-u   |   | x | 3.673 s +-  0.028 s    | 3.660 s +-  0.035 s   |  99.6%
    m-u   | x |   | 3.959 s +-  0.073 s    | 3.904 s +-  0.051 s   |  98.6%
    m-u   | x | x | 417.0 ms +-  13.0 ms   | 406.2 ms +-   6.5 ms  |  97.4%
    l-d-r |   |   | 534.3 ms +-  12.2 ms   | 537.9 ms +-   8.8 ms  | 100.7%
    l-d-r |   | x | 10.671 s +-  0.275 s   | 10.111 s +-  0.114 s  |  94.8% <--
    l-d-r | x |   | 309.7 ms +-   3.5 ms   | 307.9 ms +-   4.0 ms  |  99.4%
    l-d-r | x | x | 1.837 s +-  0.014 s    | 1.887 s +-  0.035 s   | 102.7%

Differential Revision: https://phab.mercurial-scm.org/D4371

Our full contribution guidelines are in our wiki, please see:

https://www.mercurial-scm.org/wiki/ContributingChanges

If you just want a checklist to follow, you can go straight to

https://www.mercurial-scm.org/wiki/ContributingChanges#Submission_checklist

If you can't run the entire testsuite for some reason (it can be
difficult on Windows), please at least run `contrib/check-code.py` on
any files you've modified and run `python contrib/check-commit` on any
commits you've made (for example, `python contrib/check-commit
273ce12ad8f1` will report some style violations on a very old commit).