largefiles: optimize update speed by only updating changed largefiles
Historically, during 'hg update', every largefile in the working copy was
hashed (which is a very expensive operation on big files) and any
largefiles that did not have a hash that matched their standin were
updated.
This patch optimizes 'hg update' by keeping track of what standins have
changed between the old and new revisions, and only updating the largefiles
that have changed. This saves a lot of time by avoiding the unecessary
calculation of a list of sha1 hashes for big files.
With this patch, the time 'hg update' takes to complete is a function of
how many largefiles need to be updated and what their size is.
Performance tests on a repository with about 80 largefiles ranging from
a few MB to about 97 MB are shown below. The tests show how long it takes
to run 'hg update' with no changes actually being updated.
Mercurial 2.1 release:
$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
getting changed largefiles
0 largefiles updated, 0 removed
real 0m10.045s
user 0m9.367s
sys 0m0.674s
With this patch:
$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
real 0m0.965s
user 0m0.845s
sys 0m0.115s
The same repsoitory, without the largefiles extension enabled:
$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
real 0m0.799s
user 0m0.684s
sys 0m0.111s
So before the patch, 'hg update' with no changes was approximately 9.25s
slower with largefiles enabled. With this patch, it is approximately 0.165s
slower.
$ catpatch() {
> cat $1 | sed -e "s/^\(# Parent \).*/\1/"
> }
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ runtest() {
> hg init mq
> cd mq
>
> echo a > a
> hg ci -Ama
>
> echo '% qnew should refuse bad patch names'
> hg qnew series
> hg qnew status
> hg qnew guards
> hg qnew .
> hg qnew ..
> hg qnew .hgignore
> hg qnew .mqfoo
> hg qnew 'foo#bar'
> hg qnew 'foo:bar'
>
> hg qinit -c
>
> echo '% qnew with name containing slash'
> hg qnew foo/
> hg qnew foo/bar.patch
> hg qnew foo
> hg qseries
> hg qpop
> hg qdelete foo/bar.patch
>
> echo '% qnew with uncommitted changes'
> echo a > somefile
> hg add somefile
> hg qnew uncommitted.patch
> hg st
> hg qseries
>
> echo '% qnew implies add'
> hg -R .hg/patches st
>
> echo '% qnew missing'
> hg qnew missing.patch missing
>
> echo '% qnew -m'
> hg qnew -m 'foo bar' mtest.patch
> catpatch .hg/patches/mtest.patch
>
> echo '% qnew twice'
> hg qnew first.patch
> hg qnew first.patch
>
> touch ../first.patch
> hg qimport ../first.patch
>
> echo '% qnew -f from a subdirectory'
> hg qpop -a
> mkdir d
> cd d
> echo b > b
> hg ci -Am t
> echo b >> b
> hg st
> hg qnew -g -f p
> catpatch ../.hg/patches/p
>
> echo '% qnew -u with no username configured'
> HGUSER= hg qnew -u blue red
> catpatch ../.hg/patches/red
>
> echo '% qnew -e -u with no username configured'
> HGUSER= hg qnew -e -u chartreuse fucsia
> catpatch ../.hg/patches/fucsia
>
> echo '% fail when trying to import a merge'
> hg init merge
> cd merge
> touch a
> hg ci -Am null
> echo a >> a
> hg ci -m a
> hg up -r 0
> echo b >> a
> hg ci -m b
> hg merge -f 1
> hg resolve --mark a
> hg qnew -f merge
>
> cd ../../..
> rm -r mq
> }
plain headers
$ echo "[mq]" >> $HGRCPATH
$ echo "plain=true" >> $HGRCPATH
$ mkdir sandbox
$ (cd sandbox ; runtest)
adding a
% qnew should refuse bad patch names
abort: "series" cannot be used as the name of a patch
abort: "status" cannot be used as the name of a patch
abort: "guards" cannot be used as the name of a patch
abort: "." cannot be used as the name of a patch
abort: ".." cannot be used as the name of a patch
abort: patch name cannot begin with ".hg"
abort: patch name cannot begin with ".mq"
abort: "#" cannot be used in the name of a patch
abort: ":" cannot be used in the name of a patch
% qnew with name containing slash
abort: path ends in directory separator: foo/
abort: "foo" already exists as a directory
foo/bar.patch
popping foo/bar.patch
patch queue now empty
% qnew with uncommitted changes
uncommitted.patch
% qnew implies add
A .hgignore
A series
A uncommitted.patch
% qnew missing
abort: missing: * (glob)
% qnew -m
foo bar
% qnew twice
abort: patch "first.patch" already exists
abort: patch "first.patch" already exists
% qnew -f from a subdirectory
popping first.patch
popping mtest.patch
popping uncommitted.patch
patch queue now empty
adding d/b
M d/b
diff --git a/d/b b/d/b
--- a/d/b
+++ b/d/b
@@ -1,1 +1,2 @@
b
+b
% qnew -u with no username configured
From: blue
% qnew -e -u with no username configured
From: chartreuse
% fail when trying to import a merge
adding a
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
created new head
merging a
warning: conflicts during merge.
merging a incomplete! (edit conflicts, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
abort: cannot manage merge changesets
$ rm -r sandbox
hg headers
$ echo "plain=false" >> $HGRCPATH
$ mkdir sandbox
$ (cd sandbox ; runtest)
adding a
% qnew should refuse bad patch names
abort: "series" cannot be used as the name of a patch
abort: "status" cannot be used as the name of a patch
abort: "guards" cannot be used as the name of a patch
abort: "." cannot be used as the name of a patch
abort: ".." cannot be used as the name of a patch
abort: patch name cannot begin with ".hg"
abort: patch name cannot begin with ".mq"
abort: "#" cannot be used in the name of a patch
abort: ":" cannot be used in the name of a patch
% qnew with name containing slash
abort: path ends in directory separator: foo/
abort: "foo" already exists as a directory
foo/bar.patch
popping foo/bar.patch
patch queue now empty
% qnew with uncommitted changes
uncommitted.patch
% qnew implies add
A .hgignore
A series
A uncommitted.patch
% qnew missing
abort: missing: * (glob)
% qnew -m
# HG changeset patch
# Parent
foo bar
% qnew twice
abort: patch "first.patch" already exists
abort: patch "first.patch" already exists
% qnew -f from a subdirectory
popping first.patch
popping mtest.patch
popping uncommitted.patch
patch queue now empty
adding d/b
M d/b
# HG changeset patch
# Parent
diff --git a/d/b b/d/b
--- a/d/b
+++ b/d/b
@@ -1,1 +1,2 @@
b
+b
% qnew -u with no username configured
# HG changeset patch
# Parent
# User blue
% qnew -e -u with no username configured
# HG changeset patch
# Parent
# User chartreuse
% fail when trying to import a merge
adding a
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
created new head
merging a
warning: conflicts during merge.
merging a incomplete! (edit conflicts, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
abort: cannot manage merge changesets
$ rm -r sandbox