view tests/test-pull.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.

#require serve

  $ hg init test
  $ cd test

  $ echo foo>foo
  $ hg addremove
  adding foo
  $ hg commit -m 1

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions

  $ hg serve -p $HGPORT -d --pid-file=hg.pid
  $ cat hg.pid >> $DAEMON_PIDS
  $ cd ..

  $ hg clone --pull http://foo:bar@localhost:$HGPORT/ copy
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd copy
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions

  $ hg co
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat foo
  foo

  $ hg manifest --debug
  2ed2a3912a0b24502043eae84ee4b279c18b90dd 644   foo

  $ hg pull
  pulling from http://foo@localhost:$HGPORT/
  searching for changes
  no changes found

  $ hg rollback --dry-run --verbose
  repository tip rolled back to revision -1 (undo pull: http://foo:***@localhost:$HGPORT/)

Issue622: hg init && hg pull -u URL doesn't checkout default branch

  $ cd ..
  $ hg init empty
  $ cd empty
  $ hg pull -u ../test
  pulling from ../test
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Test 'file:' uri handling:

  $ hg pull -q file://../test-does-not-exist
  abort: file:// URLs can only refer to localhost
  [255]

  $ hg pull -q file://../test
  abort: file:// URLs can only refer to localhost
  [255]

  $ hg pull -q file:../test  # no-msys

It's tricky to make file:// URLs working on every platform with
regular shell commands.

  $ URL=`$PYTHON -c "import os; print 'file://foobar' + ('/' + os.getcwd().replace(os.sep, '/')).replace('//', '/') + '/../test'"`
  $ hg pull -q "$URL"
  abort: file:// URLs can only refer to localhost
  [255]

  $ URL=`$PYTHON -c "import os; print 'file://localhost' + ('/' + os.getcwd().replace(os.sep, '/')).replace('//', '/') + '/../test'"`
  $ hg pull -q "$URL"

  $ cd ..