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
==========================================================
Test file dedicated to checking side-data related behavior
==========================================================
Check data can be written/read from sidedata
============================================
$ cat << EOF >> $HGRCPATH
> [extensions]
> testsidedata=$TESTDIR/testlib/ext-sidedata.py
> EOF
$ hg init test-sidedata --config experimental.revlogv2=enable-unstable-format-and-corrupt-my-data
$ cd test-sidedata
$ echo aaa > a
$ hg add a
$ hg commit -m a --traceback
$ echo aaa > b
$ hg add b
$ hg commit -m b
$ echo xxx >> a
$ hg commit -m aa
$ hg debugsidedata -c 0
2 sidedata entries
entry-0001 size 4
entry-0002 size 32
$ hg debugsidedata -c 1 -v
2 sidedata entries
entry-0001 size 4
'\x00\x00\x006'
entry-0002 size 32
'\x98\t\xf9\xc4v\xf0\xc5P\x90\xf7wRf\xe8\xe27e\xfc\xc1\x93\xa4\x96\xd0\x1d\x97\xaaG\x1d\xd7t\xfa\xde'
$ hg debugsidedata -m 2
2 sidedata entries
entry-0001 size 4
entry-0002 size 32
$ hg debugsidedata a 1
2 sidedata entries
entry-0001 size 4
entry-0002 size 32
$ hg debug-revlog-index --verbose -c
rev rank linkrev nodeid p1-rev p1-nodeid p2-rev p2-nodeid full-size delta-base flags comp-mode data-offset chunk-size sd-comp-mode sidedata-offset sd-chunk-size
0 -1 0 7049e48789d7 -1 000000000000 -1 000000000000 54 0 0 0 0 54 plain 0 90
1 -1 1 2707720c6597 0 7049e48789d7 -1 000000000000 54 1 0 0 54 54 plain 90 90
2 -1 2 40f977031323 1 2707720c6597 -1 000000000000 55 2 0 0 108 55 plain 180 90
$ hg debug-revlog-index --verbose -m
rev rank linkrev nodeid p1-rev p1-nodeid p2-rev p2-nodeid full-size delta-base flags comp-mode data-offset chunk-size sd-comp-mode sidedata-offset sd-chunk-size
0 -1 0 b85d294330e3 -1 000000000000 -1 000000000000 43 0 0 0 0 43 plain 0 90
1 -1 1 1a0aec305c63 0 b85d294330e3 -1 000000000000 86 0 0 0 43 55 plain 90 90
2 -1 2 104258a4f75f 1 1a0aec305c63 -1 000000000000 86 1 0 0 98 55 plain 180 90
Check upgrade behavior
======================
Right now, sidedata has not upgrade support
Check that we can upgrade to sidedata
-------------------------------------
$ hg init up-no-side-data --config experimental.revlogv2=no
$ hg debugformat -v -R up-no-side-data | grep -E 'changelog-v2|revlog-v2'
revlog-v2: no no no
changelog-v2: no no no
$ hg debugformat -v -R up-no-side-data --config experimental.revlogv2=enable-unstable-format-and-corrupt-my-data | grep -E 'changelog-v2|revlog-v2'
revlog-v2: no yes no
changelog-v2: no no no
$ hg debugupgraderepo -R up-no-side-data --config experimental.revlogv2=enable-unstable-format-and-corrupt-my-data > /dev/null
Check that we can downgrade from sidedata
-----------------------------------------
$ hg init up-side-data --config experimental.revlogv2=enable-unstable-format-and-corrupt-my-data
$ hg debugformat -v -R up-side-data | grep -E 'changelog-v2|revlog-v2'
revlog-v2: yes no no
changelog-v2: no no no
$ hg debugformat -v -R up-side-data --config experimental.revlogv2=no | grep -E 'changelog-v2|revlog-v2'
revlog-v2: yes no no
changelog-v2: no no no
$ hg debugupgraderepo -R up-side-data --config experimental.revlogv2=no > /dev/null