tags-cache: directly perform a monimal walk for hgtagsfnodescache warming
We do something narrower than the path retrieving data. So lets use dedicated
code instead.
This provides further useful speedup:
### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog
# benchmark.name = hg.debug.debug-update-cache
# bin-env-vars.hg.flavor = default
# bin-env-vars.hg.py-re2-module = default
# benchmark.variants.pre-state = warm
before-this-series: 19.947581
skip-fnode-filter: 18.916804 (-5.17%, -1.03)
use-rev-num: 17.493725 (-12.30%, -2.45)
this-changesets: 15.919466 (-20.19%, -4.03)
=============================================================
Check that we can compute and exchange revision rank properly
=============================================================
$ cat << EOF >> $HGRCPATH
> [format]
> exp-use-changelog-v2=enable-unstable-format-and-corrupt-my-data
> EOF
Test minimal rank computation with merge
$ hg init rank-repo-minimal
$ cd rank-repo-minimal
$ touch 0
$ hg commit -Aqm 0
$ touch 1
$ hg commit -Aqm 1
$ hg update -qr 0
$ touch 2
$ hg commit -Aqm 2
$ hg merge -qr 1
$ hg commit -m 3
$ touch 4
$ hg commit -Aqm 4
$ hg log --graph --template '{rev} {_fast_rank}\n'
@ 4 5
|
o 3 4
|\
| o 2 2
| |
o | 1 2
|/
o 0 1
$ cd ..
Build a bigger example repo
$ hg init rank-repo-generated
$ cd rank-repo-generated
$ hg debugbuilddag '.:root1+5:mp1<root1+10:mp2/mp1+3<mp1+2:mp3/mp2$+15/mp1+4'
$ hg log -G -T '{desc}'
o r42
|
o r41
|
o r40
|
o r39
|
o r38
|\
| o r37
| |
| o r36
| |
| o r35
| |
| o r34
| |
| o r33
| |
| o r32
| |
| o r31
| |
| o r30
| |
| o r29
| |
| o r28
| |
| o r27
| |
| o r26
| |
| o r25
| |
| o r24
| |
| o r23
|
| o r22
| |\
| | o r21
| | |
+---o r20
| |
| | o r19
| | |
| | o r18
| | |
| | o r17
| | |
+---o r16
| |/
| o r15
| |
| o r14
| |
| o r13
| |
| o r12
| |
| o r11
| |
| o r10
| |
| o r9
| |
| o r8
| |
| o r7
| |
| o r6
| |
o | r5
| |
o | r4
| |
o | r3
| |
o | r2
| |
o | r1
|/
o r0
Check the rank
--------------
$ hg log -G -T '{_fast_rank}'
o 26
|
o 25
|
o 24
|
o 23
|
o 22
|\
| o 15
| |
| o 14
| |
| o 13
| |
| o 12
| |
| o 11
| |
| o 10
| |
| o 9
| |
| o 8
| |
| o 7
| |
| o 6
| |
| o 5
| |
| o 4
| |
| o 3
| |
| o 2
| |
| o 1
|
| o 19
| |\
| | o 8
| | |
+---o 7
| |
| | o 20
| | |
| | o 19
| | |
| | o 18
| | |
+---o 17
| |/
| o 11
| |
| o 10
| |
| o 9
| |
| o 8
| |
| o 7
| |
| o 6
| |
| o 5
| |
| o 4
| |
| o 3
| |
| o 2
| |
o | 6
| |
o | 5
| |
o | 4
| |
o | 3
| |
o | 2
|/
o 1