Mercurial > hg
view tests/test-remotefilelog-sparse.t @ 44363:f7459da77f23
nodemap: introduce an option to use mmap to read the nodemap mapping
The performance and memory benefit is much greater if we don't have to copy all
the data in memory for each information. So we introduce an option (on by
default) to read the data using mmap.
This changeset is the last one definition the API for index support nodemap
data. (they have to be able to use the mmaping).
Below are some benchmark comparing the best we currently have in 5.3 with the
final step of this series (using the persistent nodemap implementation in
Rust). The benchmark run `hg perfindex` with various revset and the following
variants:
Before:
* do not use the persistent nodemap
* use the CPython implementation of the index for nodemap
* use mmapping of the changelog index
After:
* use the MixedIndex Rust code, with the NodeTree object for nodemap access
(still in review)
* use the persistent nodemap data from disk
* access the persistent nodemap data through mmap
* use mmapping of the changelog index
The persistent nodemap greatly speed up most operation on very large
repositories. Some of the previously very fast lookup end up a bit slower because
the persistent nodemap has to be setup. However the absolute slowdown is very
small and won't matters in the big picture.
Here are some numbers (in seconds) for the reference copy of mozilla-try:
Revset Before After abs-change speedup
-10000: 0.004622 0.005532 0.000910 × 0.83
-10: 0.000050 0.000132 0.000082 × 0.37
tip 0.000052 0.000085 0.000033 × 0.61
0 + (-10000:) 0.028222 0.005337 -0.022885 × 5.29
0 0.023521 0.000084 -0.023437 × 280.01
(-10000:) + 0 0.235539 0.005308 -0.230231 × 44.37
(-10:) + :9 0.232883 0.000180 -0.232703 ×1293.79
(-10000:) + (:99) 0.238735 0.005358 -0.233377 × 44.55
:99 + (-10000:) 0.317942 0.005593 -0.312349 × 56.84
:9 + (-10:) 0.313372 0.000179 -0.313193 ×1750.68
:9 0.316450 0.000143 -0.316307 ×2212.93
On smaller repositories, the cost of nodemap related operation is not as big, so
the win is much more modest. Yet it helps shaving a handful of millisecond here
and there.
Here are some numbers (in seconds) for the reference copy of mercurial:
Revset Before After abs-change speedup
-10: 0.000065 0.000097 0.000032 × 0.67
tip 0.000063 0.000078 0.000015 × 0.80
0 0.000561 0.000079 -0.000482 × 7.10
-10000: 0.004609 0.003648 -0.000961 × 1.26
0 + (-10000:) 0.005023 0.003715 -0.001307 × 1.35
(-10:) + :9 0.002187 0.000108 -0.002079 ×20.25
(-10000:) + 0 0.006252 0.003716 -0.002536 × 1.68
(-10000:) + (:99) 0.006367 0.003707 -0.002660 × 1.71
:9 + (-10:) 0.003846 0.000110 -0.003736 ×34.96
:9 0.003854 0.000099 -0.003755 ×38.92
:99 + (-10000:) 0.007644 0.003778 -0.003866 × 2.02
Differential Revision: https://phab.mercurial-scm.org/D7894
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
---|---|
date | Tue, 11 Feb 2020 11:18:52 +0100 |
parents | d7304434390f |
children | f90a5c211251 |
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#require no-windows $ . "$TESTDIR/remotefilelog-library.sh" $ hg init master $ cd master $ cat >> .hg/hgrc <<EOF > [remotefilelog] > server=True > EOF $ echo x > x $ echo z > z $ hg commit -qAm x1 $ echo x2 > x $ echo z2 > z $ hg commit -qAm x2 $ hg bookmark foo $ cd .. # prefetch a revision w/ a sparse checkout $ hgcloneshallow ssh://user@dummy/master shallow --noupdate streaming all changes 2 files to transfer, 527 bytes of data transferred 527 bytes in 0.* seconds (*/sec) (glob) searching for changes no changes found $ cd shallow $ printf "[extensions]\nsparse=\n" >> .hg/hgrc $ hg debugsparse -I x $ hg prefetch -r 0 1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob) $ hg cat -r 0 x x $ hg debugsparse -I z $ hg prefetch -r 0 1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob) $ hg cat -r 0 z z # prefetch sparse only on pull when configured $ printf "[remotefilelog]\npullprefetch=bookmark()\n" >> .hg/hgrc $ hg strip tip saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/876b1317060d-b2e91d8d-backup.hg (glob) $ hg debugsparse --delete z $ clearcache $ hg pull pulling from ssh://user@dummy/master searching for changes adding changesets adding manifests adding file changes updating bookmark foo added 1 changesets with 0 changes to 0 files new changesets 876b1317060d (run 'hg update' to get a working copy) prefetching file contents 1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob) # Dont consider filtered files when doing copy tracing ## Push an unrelated commit $ cd ../ $ hgcloneshallow ssh://user@dummy/master shallow2 streaming all changes 2 files to transfer, 527 bytes of data transferred 527 bytes in 0.* seconds (*) (glob) searching for changes no changes found updating to branch default 2 files updated, 0 files merged, 0 files removed, 0 files unresolved 1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob) $ cd shallow2 $ printf "[extensions]\nsparse=\n" >> .hg/hgrc $ hg up -q 0 2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob) $ touch a $ hg ci -Aqm a $ hg push -q -f ## Pull the unrelated commit and rebase onto it - verify unrelated file was not pulled $ cd ../shallow $ hg up -q 1 $ hg pull -q $ hg debugsparse -I z $ clearcache $ hg prefetch -r '. + .^' -I x -I z 4 files fetched over 1 fetches - (4 misses, 0.00% hit ratio) over * (glob) $ hg rebase -d 2 --keep rebasing 1:876b1317060d "x2" (foo)