Mercurial > hg
annotate README.rst @ 42743:8c9a6adec67a
rust-discovery: using the children cache in add_missing
The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.
The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.
This is a case where staying on the same side of the interface
between the two languages has clear benefits.
On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.
For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:
Rust version with simple iteration
addcommons: 57.287us
first undecided computation: 184.278334ms
first children cache computation: 131.056us
addmissings iteration: 42.766us
first addinfo total: 185.24 ms
Python + C version
first addcommons: 0.29 ms
addcommons 0.21 ms
first undecided computation 191.35 ms
addmissings 45.75 ms
first addinfo total: 237.77 ms
On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:
Rust version:
first undecided computation: 293.842629ms
first children cache computation: 407.911297ms
addmissings iteration: 34.312869ms
first addinfo total: 776.02 ms
taking initial sample
query 2: sampling time: 1318.38 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings: 143.062us
Python + C version:
first undecided computation 298.13 ms
addmissings 80.13 ms
first addinfo total: 399.62 ms
taking initial sample
query 2: sampling time: 3957.23 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings 52.88 ms
Differential Revision: https://phab.mercurial-scm.org/D6428
author | Georges Racinet <georges.racinet@octobus.net> |
---|---|
date | Tue, 16 Apr 2019 01:16:39 +0200 |
parents | 1b59287a1cfa |
children | c5912e35d06d |
rev | line source |
---|---|
12857
a9f91c844a3b
README: add small introduction
Martin Geisler <mg@lazybytes.net>
parents:
12856
diff
changeset
|
1 Mercurial |
a9f91c844a3b
README: add small introduction
Martin Geisler <mg@lazybytes.net>
parents:
12856
diff
changeset
|
2 ========= |
a9f91c844a3b
README: add small introduction
Martin Geisler <mg@lazybytes.net>
parents:
12856
diff
changeset
|
3 |
a9f91c844a3b
README: add small introduction
Martin Geisler <mg@lazybytes.net>
parents:
12856
diff
changeset
|
4 Mercurial is a fast, easy to use, distributed revision control tool |
a9f91c844a3b
README: add small introduction
Martin Geisler <mg@lazybytes.net>
parents:
12856
diff
changeset
|
5 for software developers. |
a9f91c844a3b
README: add small introduction
Martin Geisler <mg@lazybytes.net>
parents:
12856
diff
changeset
|
6 |
33618
76b171209151
README: make paragraphs before example code end with "::" for reST syntax
FUJIWARA Katsunori <foozy@lares.dti.ne.jp>
parents:
26421
diff
changeset
|
7 Basic install:: |
0
9117c6561b0b
Add back links from file revisions to changeset revisions
mpm@selenic.com
parents:
diff
changeset
|
8 |
3935 | 9 $ make # see install targets |
10 $ make install # do a system-wide install | |
11 $ hg debuginstall # sanity-check setup | |
12 $ hg # see help | |
205
d255d99a7cbd
README: integrate some changes from Kevin Smith
mpm@selenic.com
parents:
204
diff
changeset
|
13 |
33618
76b171209151
README: make paragraphs before example code end with "::" for reST syntax
FUJIWARA Katsunori <foozy@lares.dti.ne.jp>
parents:
26421
diff
changeset
|
14 Running without installing:: |
16217
df5ecb813426
readme: mention how to run in-place
Ross Lagerwall <rosslagerwall@gmail.com>
parents:
12857
diff
changeset
|
15 |
df5ecb813426
readme: mention how to run in-place
Ross Lagerwall <rosslagerwall@gmail.com>
parents:
12857
diff
changeset
|
16 $ make local # build for inplace usage |
df5ecb813426
readme: mention how to run in-place
Ross Lagerwall <rosslagerwall@gmail.com>
parents:
12857
diff
changeset
|
17 $ ./hg --version # should show the latest version |
df5ecb813426
readme: mention how to run in-place
Ross Lagerwall <rosslagerwall@gmail.com>
parents:
12857
diff
changeset
|
18 |
26421
4b0fc75f9403
urls: bulk-change primary website URLs
Matt Mackall <mpm@selenic.com>
parents:
16217
diff
changeset
|
19 See https://mercurial-scm.org/ for detailed installation |
3935 | 20 instructions, platform-specific notes, and Mercurial user information. |