Mercurial > hg
view tests/test-issue1306.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 | eb586ed5d8ce |
children |
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https://bz.mercurial-scm.org/1306 Initialize remote repo with branches: $ hg init remote $ cd remote $ echo a > a $ hg ci -Ama adding a $ hg branch br marked working directory as branch br (branches are permanent and global, did you want a bookmark?) $ hg ci -Amb $ echo c > c $ hg ci -Amc adding c $ hg log changeset: 2:ae3d9c30ec50 branch: br tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: c changeset: 1:3f7f930ca414 branch: br user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: b changeset: 0:cb9a9f314b8b user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: a $ cd .. Try cloning -r branch: $ hg clone -rbr remote local1 adding changesets adding manifests adding file changes added 3 changesets with 2 changes to 2 files new changesets cb9a9f314b8b:ae3d9c30ec50 updating to branch br 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg -R local1 parents changeset: 2:ae3d9c30ec50 branch: br tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: c Try cloning -rother clone#branch: $ hg clone -r0 remote#br local2 adding changesets adding manifests adding file changes added 3 changesets with 2 changes to 2 files new changesets cb9a9f314b8b:ae3d9c30ec50 updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg -R local2 parents changeset: 0:cb9a9f314b8b user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: a Try cloning -r1 clone#branch: $ hg clone -r1 remote#br local3 adding changesets adding manifests adding file changes added 3 changesets with 2 changes to 2 files new changesets cb9a9f314b8b:ae3d9c30ec50 updating to branch br 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg -R local3 parents changeset: 1:3f7f930ca414 branch: br user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: b