Mercurial > hg-stable
view tests/test-filebranch.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 | 7e9cbb9c6053 |
children | 2428e8ec0793 |
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This test makes sure that we don't mark a file as merged with its ancestor when we do a merge. $ cat <<EOF > merge > import sys, os > print "merging for", os.path.basename(sys.argv[1]) > EOF $ HGMERGE="python ../merge"; export HGMERGE Creating base: $ hg init a $ cd a $ echo 1 > foo $ echo 1 > bar $ echo 1 > baz $ echo 1 > quux $ hg add foo bar baz quux $ hg commit -m "base" $ cd .. $ hg clone a b updating to branch default 4 files updated, 0 files merged, 0 files removed, 0 files unresolved Creating branch a: $ cd a $ echo 2a > foo $ echo 2a > bar $ hg commit -m "branch a" Creating branch b: $ cd .. $ cd b $ echo 2b > foo $ echo 2b > baz $ hg commit -m "branch b" We shouldn't have anything but n state here: $ hg debugstate --nodates | grep -v "^n" [1] Merging: $ hg pull ../a pulling from ../a searching for changes adding changesets adding manifests adding file changes added 1 changesets with 2 changes to 2 files (+1 heads) (run 'hg heads' to see heads, 'hg merge' to merge) $ hg merge -v resolving manifests getting bar merging foo merging for foo 1 files updated, 1 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ echo 2m > foo $ echo 2b > baz $ echo new > quux $ hg ci -m "merge" main: we should have a merge here: $ hg debugindex --changelog rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 73 ..... 0 cdca01651b96 000000000000 000000000000 (re) 1 73 68 ..... 1 f6718a9cb7f3 cdca01651b96 000000000000 (re) 2 141 68 ..... 2 bdd988058d16 cdca01651b96 000000000000 (re) 3 209 66 ..... 3 d8a521142a3c f6718a9cb7f3 bdd988058d16 (re) log should show foo and quux changed: $ hg log -v -r tip changeset: 3:d8a521142a3c tag: tip parent: 1:f6718a9cb7f3 parent: 2:bdd988058d16 user: test date: Thu Jan 01 00:00:00 1970 +0000 files: foo quux description: merge foo: we should have a merge here: $ hg debugindex foo rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 3 ..... 0 b8e02f643373 000000000000 000000000000 (re) 1 3 4 ..... 1 2ffeddde1b65 b8e02f643373 000000000000 (re) 2 7 4 ..... 2 33d1fb69067a b8e02f643373 000000000000 (re) 3 11 4 ..... 3 aa27919ee430 2ffeddde1b65 33d1fb69067a (re) bar: we should not have a merge here: $ hg debugindex bar rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 3 ..... 0 b8e02f643373 000000000000 000000000000 (re) 1 3 4 ..... 2 33d1fb69067a b8e02f643373 000000000000 (re) baz: we should not have a merge here: $ hg debugindex baz rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 3 ..... 0 b8e02f643373 000000000000 000000000000 (re) 1 3 4 ..... 1 2ffeddde1b65 b8e02f643373 000000000000 (re) quux: we should not have a merge here: $ hg debugindex quux rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 3 ..... 0 b8e02f643373 000000000000 000000000000 (re) 1 3 5 ..... 3 6128c0f33108 b8e02f643373 000000000000 (re) Manifest entries should match tips of all files: $ hg manifest --debug 33d1fb69067a0139622a3fa3b7ba1cdb1367972e 644 bar 2ffeddde1b65b4827f6746174a145474129fa2ce 644 baz aa27919ee4303cfd575e1fb932dd64d75aa08be4 644 foo 6128c0f33108e8cfbb4e0824d13ae48b466d7280 644 quux Everything should be clean now: $ hg status $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 4 files, 4 changesets, 10 total revisions $ cd ..