Mercurial > hg
view tests/pdiff @ 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 | a2b55ee62803 |
children |
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#!/bin/sh # Script to get stable diff output on any platform. # # Output of this script is almost equivalent to GNU diff with "-Nru". # # Use this script as "hg pdiff" via extdiff extension with preparation # below in test scripts: # # $ cat >> $HGRCPATH <<EOF # > [extdiff] # > pdiff = sh "$RUNTESTDIR/pdiff" # > EOF filediff(){ # USAGE: filediff file1 file2 [header] # compare with /dev/null if file doesn't exist (as "-N" option) file1="$1" if test ! -f "$file1"; then file1=/dev/null fi file2="$2" if test ! -f "$file2"; then file2=/dev/null fi if cmp -s "$file1" "$file2" 2> /dev/null; then # Return immediately, because comparison isn't needed. This # also avoids redundant message of diff like "No differences # encountered" (on Solaris) return fi if test -n "$3"; then # show header only in recursive case echo "$3" fi # replace "/dev/null" by corresponded filename (as "-N" option) diff -u "$file1" "$file2" | sed "s@^--- /dev/null\(.*\)\$@--- $1\1@" | sed "s@^\+\+\+ /dev/null\(.*\)\$@+++ $2\1@" # in this case, files differ from each other return 1 } if test -d "$1" -o -d "$2"; then # ensure comparison in dictionary order ( if test -d "$1"; then (cd "$1" && find . -type f); fi if test -d "$2"; then (cd "$2" && find . -type f); fi ) | sed 's@^\./@@g' | sort | uniq | while read file; do filediff "$1/$file" "$2/$file" "diff -Nru $1/$file $2/$file" done # TODO: there is no portable way for current while-read based # implementation to return 1 at detecting changes. # # On bash and dash, assignment to variable inside while-block # doesn't affect outside, because inside while-block is executed # in sub-shell. BTW, it affects outside while-block on ksh (as sh # on Solaris). else filediff "$1" "$2" fi