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
============================================================================
Pulling from modern to a non-general delta target (and other related checks)
============================================================================
There is various issue that can arise when we update the code with modern
storage in mind while working on delta processing. So this file is meant for
various scenario that might break in the future or have break in the past.
Setup
=====
Create a modern server with an older clone
$ cat << EOF >> $HGRCPATH
> [command-templates]
> log = "{desc} {tags}\n"
> EOF
$ hg init server
$ hg clone --quiet --pull server client --config format.usegeneraldelta=no
$ hg debugformat -R client | grep generaldelta
generaldelta: no
Create some complexe history
$ cd server
$ hg debugbuilddag -n '.+3:a$.+5:b/a:k$.+7:c/b:l$.+6:d/a:m<k+6/l+1/m'
$ hg log -G
o r36 tip
|\
| o r35
| |
| o r34
| |\
| | o r33
| | |
| | o r32
| | |
| | o r31
| | |
| | o r30
| | |
| | o r29
| | |
| | o r28
| | |
o | | r27 m
|\ \ \
| o | | r26 d
| | | |
| o | | r25
| | | |
| o | | r24
| | | |
| o | | r23
| | | |
| o | | r22
| | | |
| o | | r21
| | | |
| o | | r20
| / /
| o | r19 l
| |\ \
| | o | r18 c
| | | |
| | o | r17
| | | |
| | o | r16
| | | |
| | o | r15
| | | |
| | o | r14
| | | |
| | o | r13
| | | |
| | o | r12
| | | |
| | o | r11
| | /
+---o r10 k
| |/
| o r9 b
| |
| o r8
| |
| o r7
| |
| o r6
| |
| o r5
| |
| o r4
|
o r3 a
|
o r2
|
o r1
|
o r0
$ cd ..
Pull it in the client
=====================
pull with default value
-----------------------
$ cp -R client client-simple-pull
$ hg -R client-simple-pull pull
pulling from $TESTTMP/server
requesting all changes
adding changesets
adding manifests
adding file changes
added 37 changesets with 37 changes to 37 files
new changesets 61246295ee1e:b4b117cbbcf3
(run 'hg update' to get a working copy)
$ hg -R client-simple-pull verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checking dirstate
checked 37 changesets with 37 changes to 37 files
pull with "no-reuse" policy
---------------------------
$ cp -R client client-no-reuse
$ hg -R client-no-reuse pull --config paths.default:pulled-delta-reuse-policy=no-reuse
pulling from $TESTTMP/server
requesting all changes
adding changesets
adding manifests
adding file changes
added 37 changesets with 37 changes to 37 files
new changesets 61246295ee1e:b4b117cbbcf3
(run 'hg update' to get a working copy)
$ hg -R client-no-reuse verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checking dirstate
checked 37 changesets with 37 changes to 37 files
pull with "try-base" policy
---------------------------
$ cp -R client client-try-base
$ hg -R client-try-base pull --config paths.default:pulled-delta-reuse-policy=try-base
pulling from $TESTTMP/server
requesting all changes
adding changesets
adding manifests
adding file changes
added 37 changesets with 37 changes to 37 files
new changesets 61246295ee1e:b4b117cbbcf3
(run 'hg update' to get a working copy)
$ hg -R client-try-base verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checking dirstate
checked 37 changesets with 37 changes to 37 files
pull with "forced" policy
-------------------------
$ cp -R client client-forced
$ hg -R client-forced paths --config paths.default:pulled-delta-reuse-policy=forced
default = $TESTTMP/server
default:pulled-delta-reuse-policy = forced
$ hg -R client-forced pull --config paths.default:pulled-delta-reuse-policy=forced
pulling from $TESTTMP/server
requesting all changes
adding changesets
adding manifests
adding file changes
added 37 changesets with 37 changes to 37 files
new changesets 61246295ee1e:b4b117cbbcf3
(run 'hg update' to get a working copy)
$ hg -R client-forced verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checking dirstate
checked 37 changesets with 37 changes to 37 files