phases: rework the logic of _pushdiscoveryphase to bound complexity This rework the various graph traversal in _pushdiscoveryphase to keep the complexity in check. This is done though a couple of things: - first, limiting the space we have to explore, for example, if we are not in publishing push, we don't need to consider remote draft roots that are also draft locally, as there is nothing to be moved there. - avoid unbounded descendant computation, and use the faster "rev between" computation. This provide a massive boost to performance when exchanging with repository with a massive amount of draft, like mozilla-try: ### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog # benchmark.name = hg.command.push # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default # benchmark.variants.explicit-rev = all-out-heads # benchmark.variants.issue6528 = disabled # benchmark.variants.protocol = ssh # benchmark.variants.reuse-external-delta-parent = default ## benchmark.variants.revs = any-1-extra-rev before: 20.346590 seconds after: 11.232059 seconds (-38.15%, -7.48 seconds) ## benchmark.variants.revs = any-100-extra-rev before: 24.752051 seconds after: 15.367412 seconds (-37.91%, -9.38 seconds) After this changes, the push operation is still quite too slow. Some of this can be attributed to general phases slowness (reading all the roots from disk for example) and other know slowness (not using persistent-nodemap, branchmap, tags, etc. We are also working on them, but with this series, phase discovery during push no longer showing up in profile and this is a pretty nice and bit low-hanging fruit out of the way. ### (same case as the above) # benchmark.variants.revs = any-1-extra-rev pre-%ln-change: 44.235070 this-changeset: 11.232059 seconds (-74.61%, -33.00 seconds) # benchmark.variants.revs = any-100-extra-rev pre-%ln-change: 49.234697 this-changeset: 15.367412 seconds (-68.79%, -33.87 seconds) Note that with this change, the `hg push` performance is now much closer to the `hg pull` performance, even it still lagging behind a bit. (and the overall performance are still too slow). ### data-env-vars.name = mozilla-try-2023-03-22-ds2-pnm # benchmark.variants.explicit-rev = all-out-heads # benchmark.variants.issue6528 = disabled # benchmark.variants.protocol = ssh # benchmark.variants.pulled-delta-reuse-policy = default # bin-env-vars.hg.flavor = rust ## benchmark.variants.revs = any-1-extra-rev hg.command.pull: 6.517450 hg.command.push: 11.219888 ## benchmark.variants.revs = any-100-extra-rev hg.command.pull: 10.160991 hg.command.push: 14.251107 ### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog # bin-env-vars.hg.py-re2-module = default # benchmark.variants.explicit-rev = all-out-heads # benchmark.variants.issue6528 = disabled # benchmark.variants.protocol = ssh # benchmark.variants.pulled-delta-reuse-policy = default ## bin-env-vars.hg.flavor = default ## benchmark.variants.revs = any-1-extra-rev hg.command.pull: 8.577772 hg.command.push: 11.232059 ## bin-env-vars.hg.flavor = default ## benchmark.variants.revs = any-100-extra-rev hg.command.pull: 13.152976 hg.command.push: 15.367412 ## bin-env-vars.hg.flavor = rust ## benchmark.variants.revs = any-1-extra-rev hg.command.pull: 8.731982 hg.command.push: 11.178751 ## bin-env-vars.hg.flavor = rust ## benchmark.variants.revs = any-100-extra-rev hg.command.pull: 13.184236 hg.command.push: 15.620843

     1

  $ hg init a

     2

  $ cd a

     3

  $ echo a > a

     4

  $ hg ci -Am0

     5

  adding a

     6

  $ echo b > b

     7

  $ hg ci -Am1

     8

  adding b

     9

  $ hg tag -r0 default

    10

  warning: tag default conflicts with existing branch name

    11

  $ hg log

    12

  changeset:   2:30a83d1e4a1e

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  tag:         tip

    14

  user:        test

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  date:        Thu Jan 01 00:00:00 1970 +0000

    16

  summary:     Added tag default for changeset f7b1eb17ad24

    17

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  changeset:   1:925d80f479bb

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  user:        test

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  date:        Thu Jan 01 00:00:00 1970 +0000

    21

  summary:     1

    22

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  changeset:   0:f7b1eb17ad24

    24

  tag:         default

    25

  user:        test

    26

  date:        Thu Jan 01 00:00:00 1970 +0000

    27

  summary:     0

    28

    29

  $ hg update 'tag(default)'

    30

  0 files updated, 0 files merged, 2 files removed, 0 files unresolved

    31

  $ hg parents

    32

  changeset:   0:f7b1eb17ad24

    33

  tag:         default

    34

  user:        test

    35

  date:        Thu Jan 01 00:00:00 1970 +0000

    36

  summary:     0

    37

    38

  $ hg update 'branch(default)'

    39

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

    40

  $ hg parents

    41

  changeset:   2:30a83d1e4a1e

    42

  tag:         tip

    43

  user:        test

    44

  date:        Thu Jan 01 00:00:00 1970 +0000

    45

  summary:     Added tag default for changeset f7b1eb17ad24

    46

    47

    48

  $ cd ..