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 various things around delta computation within revlog
==========================================================
basic setup
-----------
$ cat << EOF >> $HGRCPATH
> [debug]
> revlog.debug-delta=yes
> EOF
$ hg init base-repo
$ cd base-repo
create a "large" file
$ $TESTDIR/seq.py 1000 | $TESTDIR/sha256line.py > my-file.txt
$ hg add my-file.txt
$ hg commit -m initial-commit
DBG-DELTAS: FILELOG:my-file.txt: rev=0: delta-base=0 * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
Add more change at the end of the file
$ $TESTDIR/seq.py 1001 1200 | $TESTDIR/sha256line.py >> my-file.txt
$ hg commit -m "large-change"
DBG-DELTAS: FILELOG:my-file.txt: rev=1: delta-base=0 * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
Add small change at the start
$ hg up 'desc("initial-commit")' --quiet
$ mv my-file.txt foo
$ echo "small change at the start" > my-file.txt
$ cat foo >> my-file.txt
$ rm foo
$ hg commit -m "small-change"
DBG-DELTAS: FILELOG:my-file.txt: rev=2: delta-base=0 * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
created new head
$ hg log -r 'head()' -T '{node}\n' >> ../base-heads.nodes
$ hg log -r 'desc("initial-commit")' -T '{node}\n' >> ../initial.node
$ hg log -r 'desc("small-change")' -T '{node}\n' >> ../small.node
$ hg log -r 'desc("large-change")' -T '{node}\n' >> ../large.node
$ cd ..
Check delta find policy and result for merge on commit
======================================================
Check that delta of merge pick best of the two parents
------------------------------------------------------
As we check against both parents, the one with the largest change should
produce the smallest delta and be picked.
$ hg clone base-repo test-parents --quiet
$ hg -R test-parents update 'nodefromfile("small.node")' --quiet
$ hg -R test-parents merge 'nodefromfile("large.node")' --quiet
The delta base is the "large" revision as it produce a smaller delta.
$ hg -R test-parents commit -m "merge from small change"
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=1 * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
Check that the behavior tested above can we disabled
----------------------------------------------------
We disable the checking of both parent at the same time. The `small` change,
that produce a less optimal delta, should be picked first as it is "closer" to
the new commit.
$ hg clone base-repo test-no-parents --quiet
$ hg -R test-no-parents update 'nodefromfile("small.node")' --quiet
$ hg -R test-no-parents merge 'nodefromfile("large.node")' --quiet
The delta base is the "large" revision as it produce a smaller delta.
$ hg -R test-no-parents commit -m "merge from small change" \
> --config storage.revlog.optimize-delta-parent-choice=no
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=2 * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
Check delta-find policy and result when unbundling
==================================================
Build a bundle with all delta built against p1
$ hg bundle -R test-parents --all --config devel.bundle.delta=p1 all-p1.hg
4 changesets found
Default policy of trusting delta from the bundle
------------------------------------------------
Keeping the `p1` delta used in the bundle is sub-optimal for storage, but
strusting in-bundle delta is faster to apply.
$ hg init bundle-default
$ hg -R bundle-default unbundle all-p1.hg --quiet
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=0: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=1: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=2: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=2 * (glob)
(confirm the file revision are in the same order, 2 should be smaller than 1)
$ hg -R bundle-default debugdata my-file.txt 2 | wc -l
\s*1001 (re)
$ hg -R bundle-default debugdata my-file.txt 1 | wc -l
\s*1200 (re)
explicitly enabled
------------------
Keeping the `p1` delta used in the bundle is sub-optimal for storage, but
strusting in-bundle delta is faster to apply.
$ hg init bundle-reuse-enabled
$ hg -R bundle-reuse-enabled unbundle all-p1.hg --quiet \
> --config storage.revlog.reuse-external-delta-parent=yes
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=0: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=1: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=2: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=2 * (glob)
(confirm the file revision are in the same order, 2 should be smaller than 1)
$ hg -R bundle-reuse-enabled debugdata my-file.txt 2 | wc -l
\s*1001 (re)
$ hg -R bundle-reuse-enabled debugdata my-file.txt 1 | wc -l
\s*1200 (re)
explicitly disabled
-------------------
Not reusing the delta-base from the parent means we the delta will be made
against the "best" parent. (so not the same as the previous two)
$ hg init bundle-reuse-disabled
$ hg -R bundle-reuse-disabled unbundle all-p1.hg --quiet \
> --config storage.revlog.reuse-external-delta-parent=no
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=0: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=1: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=2: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=1 * (glob)
(confirm the file revision are in the same order, 2 should be smaller than 1)
$ hg -R bundle-reuse-disabled debugdata my-file.txt 2 | wc -l
\s*1001 (re)
$ hg -R bundle-reuse-disabled debugdata my-file.txt 1 | wc -l
\s*1200 (re)
Check the path.*:pulled-delta-reuse-policy option
==========================================
Get a repository with the bad parent picked and a clone ready to pull the merge
$ cp -aR bundle-reuse-enabled peer-bad-delta
$ hg clone peer-bad-delta local-pre-pull --rev `cat large.node` --rev `cat small.node` --quiet
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=0: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=1: delta-base=0 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=2: delta-base=0 * (glob)
Check the parent order for the file
$ hg -R local-pre-pull debugdata my-file.txt 2 | wc -l
\s*1001 (re)
$ hg -R local-pre-pull debugdata my-file.txt 1 | wc -l
\s*1200 (re)
Pull with no value (so the default)
-----------------------------------
default is to reuse the (bad) delta
$ cp -aR local-pre-pull local-no-value
$ hg -R local-no-value pull --quiet
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=2 * (glob)
Pull with explicitly the default
--------------------------------
default is to reuse the (bad) delta
$ cp -aR local-pre-pull local-default
$ hg -R local-default pull --quiet --config 'paths.default:pulled-delta-reuse-policy=default'
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=2 * (glob)
Pull with no-reuse
------------------
We don't reuse the base, so we get a better delta
$ cp -aR local-pre-pull local-no-reuse
$ hg -R local-no-reuse pull --quiet --config 'paths.default:pulled-delta-reuse-policy=no-reuse'
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=1 * (glob)
Pull with try-base
------------------
We requested to use the (bad) delta
$ cp -aR local-pre-pull local-try-base
$ hg -R local-try-base pull --quiet --config 'paths.default:pulled-delta-reuse-policy=try-base'
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=2 * (glob)
Case where we force a "bad" delta to be applied
===============================================
We build a very different file content to force a full snapshot
$ cp -aR peer-bad-delta peer-bad-delta-with-full
$ cp -aR local-pre-pull local-pre-pull-full
$ echo '[paths]' >> local-pre-pull-full/.hg/hgrc
$ echo 'default=../peer-bad-delta-with-full' >> local-pre-pull-full/.hg/hgrc
$ hg -R peer-bad-delta-with-full update 'desc("merge")' --quiet
$ ($TESTDIR/seq.py 2000 2100; $TESTDIR/seq.py 500 510; $TESTDIR/seq.py 3000 3050) \
> | $TESTDIR/sha256line.py > peer-bad-delta-with-full/my-file.txt
$ hg -R peer-bad-delta-with-full commit -m 'trigger-full'
DBG-DELTAS: FILELOG:my-file.txt: rev=4: delta-base=4 * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
Check that "try-base" behavior challenge the delta
--------------------------------------------------
The bundling process creates a delta against the previous revision, however this
is an invalid chain for the client, so it is not considered and we do a full
snapshot again.
$ cp -aR local-pre-pull-full local-try-base-full
$ hg -R local-try-base-full pull --quiet \
> --config 'paths.default:pulled-delta-reuse-policy=try-base'
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=2 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=4: delta-base=4 * (glob)
Check that "forced" behavior do not challenge the delta, even if it is full.
---------------------------------------------------------------------------
A full bundle should be accepted as full bundle without recomputation
$ cp -aR local-pre-pull-full local-forced-full
$ hg -R local-forced-full pull --quiet \
> --config 'paths.default:pulled-delta-reuse-policy=forced'
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=2 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=4: delta-base=4 is-cached=1 - search-rounds=0 try-count=0 - delta-type=full snap-depth=0 - * (glob)
Check that "forced" behavior do not challenge the delta, even if it is bad.
---------------------------------------------------------------------------
The client does not challenge anything and applies the bizarre delta directly.
Note: If the bundling process becomes smarter, this test might no longer work
(as the server won't be sending "bad" deltas anymore) and might need something
more subtle to test this behavior.
$ hg bundle -R peer-bad-delta-with-full --all --config devel.bundle.delta=p1 all-p1.hg
5 changesets found
$ cp -aR local-pre-pull-full local-forced-full-p1
$ hg -R local-forced-full-p1 pull --quiet \
> --config 'paths.*:pulled-delta-reuse-policy=forced' all-p1.hg
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=2 is-cached=1 *search-rounds=0 try-count=0* (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=4: delta-base=3 is-cached=1 *search-rounds=0 try-count=0* (glob)
Check that running "forced" on a non-general delta repository does not corrupt it
---------------------------------------------------------------------------------
Even if requested to be used, some of the delta in the revlog cannot be stored on a non-general delta repository. We check that the bundle application was correct.
$ hg init \
> --config format.usegeneraldelta=no \
> --config format.sparse-revlog=no \
> local-forced-full-p1-no-gd
$ hg debugformat -R local-forced-full-p1-no-gd | grep generaldelta
generaldelta: no
$ hg -R local-forced-full-p1-no-gd pull --quiet local-pre-pull-full \
> --config debug.revlog.debug-delta=no
$ hg -R local-forced-full-p1-no-gd pull --quiet \
> --config 'paths.*:pulled-delta-reuse-policy=forced' all-p1.hg
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: CHANGELOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: MANIFESTLOG: * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=3: delta-base=0 * - search-rounds=1 try-count=1 * (glob)
DBG-DELTAS: FILELOG:my-file.txt: rev=4: delta-base=4 * - search-rounds=1 try-count=1 * (glob)
$ hg -R local-forced-full-p1-no-gd verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checking dirstate
checked 5 changesets with 5 changes to 1 files