Mercurial > hg-stable
view tests/test-convert-baz.t @ 26379:39d643252b9f
revlog: use existing file handle when reading during _addrevision
_addrevision() may need to read from revlogs as part of computing
deltas. Previously, we would flush existing file handles and open
a new, short-lived file handle to perform the reading.
If we have an existing file handle, it seems logical to reuse it
for reading instead of opening a new file handle. This patch
makes that the new behavior.
After this patch, revlog files are only reopened when adding
revisions if the revlog is switched from inline to non-inline.
On Linux when unbundling a bundle of the mozilla-central repo, this
patch has the following impact on system call counts:
Call Before After Delta
write 827,639 673,390 -154,249
open 700,103 684,089 -16,014
read 74,489 74,489 0
fstat 493,924 461,896 -32,028
close 249,131 233,117 -16,014
stat 242,001 242,001 0
lstat 18,676 18,676 0
lseek 20,268 20,268 0
ioctl 14,652 13,173 -1,479
TOTAL 3,180,758 2,930,679 -250,079
It's worth noting that many of the open() calls fail due to missing
files. That's why there are many more open() calls than close().
Despite the significant system call reduction, this change does not
seem to have a significant performance impact on Linux.
On Windows 10 (not a VM, on a SSD), this patch appears to reduce
unbundle time for mozilla-central from ~960s to ~920s. This isn't
as significant as I was hoping. But a decrease it is nonetheless.
Still, Windows unbundle performance is still >2x slower than Linux.
Despite the lack of significant gains, fewer system calls is fewer
system calls. If nothing else, this will narrow the focus of potential
areas to optimize in the future.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 27 Sep 2015 16:08:18 -0700 |
parents | 7a9cbb315d84 |
children | 561a019c0268 |
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#require baz symlink $ baz my-id "mercurial <mercurial@selenic.com>" $ echo "[extensions]" >> $HGRCPATH $ echo "convert=" >> $HGRCPATH create baz archive $ baz make-archive baz@mercurial--convert hg-test-convert-baz initialize baz repo $ mkdir baz-repo $ cd baz-repo/ $ baz init-tree baz@mercurial--convert/baz--test--0 $ baz import * creating version baz@mercurial--convert/baz--test--0 * imported baz@mercurial--convert/baz--test--0 create initial files $ echo 'this is a file' > a $ baz add a $ mkdir src $ baz add src $ cd src $ dd count=1 if=/dev/zero of=b > /dev/null 2> /dev/null $ baz add b HACK: hide GNU tar-1.22 "tar: The --preserve option is deprecated, use --preserve-permissions --preserve-order instead" $ baz commit -s "added a file, src and src/b (binary)" 2>&1 | grep -v '^tar' * build pristine tree for baz@mercurial--convert/baz--test--0--base-0 * Scanning for full-tree revision: . * from import revision: baz@mercurial--convert/baz--test--0--base-0 A/ .arch-ids A/ src A/ src/.arch-ids A .arch-ids/a.id A a A src/.arch-ids/=id A src/.arch-ids/b.id A src/b * update pristine tree (baz@mercurial--convert/baz--test--0--base-0 => baz--test--0--patch-1) * committed baz@mercurial--convert/baz--test--0--patch-1 create link file and modify a $ ln -s ../a a-link $ baz add a-link $ echo 'this a modification to a' >> ../a $ baz commit -s "added link to a and modify a" A src/.arch-ids/a-link.id A src/a-link M a * update pristine tree (baz@mercurial--convert/baz--test--0--patch-1 => baz--test--0--patch-2) * committed baz@mercurial--convert/baz--test--0--patch-2 create second link and modify b $ ln -s ../a a-link-2 $ baz add a-link-2 $ dd count=1 seek=1 if=/dev/zero of=b > /dev/null 2> /dev/null $ baz commit -s "added second link and modify b" A src/.arch-ids/a-link-2.id A src/a-link-2 Mb src/b * update pristine tree (baz@mercurial--convert/baz--test--0--patch-2 => baz--test--0--patch-3) * committed baz@mercurial--convert/baz--test--0--patch-3 b file to link and a-link-2 to regular file $ rm -f a-link-2 $ echo 'this is now a regular file' > a-link-2 $ ln -sf ../a b $ baz commit -s "file to link and link to file test" fl src/b lf src/a-link-2 * update pristine tree (baz@mercurial--convert/baz--test--0--patch-3 => baz--test--0--patch-4) * committed baz@mercurial--convert/baz--test--0--patch-4 move a-link-2 file and src directory $ cd .. $ baz mv src/a-link-2 c $ baz mv src test $ baz commit -s "move and rename a-link-2 file and src directory" D/ src/.arch-ids A/ test/.arch-ids /> src test => src/.arch-ids/a-link-2.id .arch-ids/c.id => src/a-link-2 c => src/.arch-ids/=id test/.arch-ids/=id => src/.arch-ids/a-link.id test/.arch-ids/a-link.id => src/.arch-ids/b.id test/.arch-ids/b.id * update pristine tree (baz@mercurial--convert/baz--test--0--patch-4 => baz--test--0--patch-5) * committed baz@mercurial--convert/baz--test--0--patch-5 move and add the moved file again $ echo e > e $ baz add e $ baz commit -s "add e" A .arch-ids/e.id A e * update pristine tree (baz@mercurial--convert/baz--test--0--patch-5 => baz--test--0--patch-6) * committed baz@mercurial--convert/baz--test--0--patch-6 $ baz mv e f $ echo ee > e $ baz add e $ baz commit -s "move e and recreate it again" A .arch-ids/e.id A e => .arch-ids/e.id .arch-ids/f.id => e f * update pristine tree (baz@mercurial--convert/baz--test--0--patch-6 => baz--test--0--patch-7) * committed baz@mercurial--convert/baz--test--0--patch-7 $ cd .. converting baz repo to Mercurial $ hg convert baz-repo baz-repo-hg initializing destination baz-repo-hg repository analyzing tree version baz@mercurial--convert/baz--test--0... scanning source... sorting... converting... 7 initial import 6 added a file, src and src/b (binary) 5 added link to a and modify a 4 added second link and modify b 3 file to link and link to file test 2 move and rename a-link-2 file and src directory 1 add e 0 move e and recreate it again $ baz register-archive -d baz@mercurial--convert $ glog() > { > hg log -G --template '{rev} "{desc|firstline}" files: {files}\n' "$@" > } show graph log $ glog -R baz-repo-hg o 7 "move e and recreate it again" files: e f | o 6 "add e" files: e | o 5 "move and rename a-link-2 file and src directory" files: c src/a-link src/a-link-2 src/b test/a-link test/b | o 4 "file to link and link to file test" files: src/a-link-2 src/b | o 3 "added second link and modify b" files: src/a-link-2 src/b | o 2 "added link to a and modify a" files: a src/a-link | o 1 "added a file, src and src/b (binary)" files: a src/b | o 0 "initial import" files: $ hg up -q -R baz-repo-hg $ hg -R baz-repo-hg manifest --debug c4072c4b72e1cabace081888efa148ee80ca3cbb 644 a 0201ac32a3a8e86e303dff60366382a54b48a72e 644 c 1a4a864db0073705a11b1439f563bfa4b46d9246 644 e 09e0222742fc3f75777fa9d68a5d8af7294cb5e7 644 f c0067ba5ff0b7c9a3eb17270839d04614c435623 644 @ test/a-link 375f4263d86feacdea7e3c27100abd1560f2a973 644 @ test/b $ hg -R baz-repo-hg log -r 5 -r 7 -C --debug | grep copies copies: c (src/a-link-2) test/a-link (src/a-link) test/b (src/b) copies: f (e)