bundle2: increase payload part chunk size to 32kb
Bundle2 payload parts are framed chunks. Esentially, we obtain
data in equal size chunks of size `preferedchunksize` and emit those
to a generator. That generator is fed into a compressor (which can
be the no-op compressor, which just re-emits the generator). And
the output from the compressor likely goes to a file descriptor
or socket.
What this means is that small chunk sizes create more Python objects
and Python function calls than larger chunk sizes. And as we know,
Python object and function call overhead in performance sensitive
code matters (at least with CPython).
This commit increases the bundle2 part payload chunk size from 4k
to 32k. Practically speaking, this means that the chunks we feed
into a compressor (implemented in C code) or feed directly into a
file handle or socket write() are larger. It's possible the chunks
might be larger than what the receiver can handle in one logical
operation. But at that point, we're in C code, which is much more
efficient at dealing with splitting up the chunk and making multiple
function calls than Python is.
A downside to larger chunks is that the receiver has to wait for that
much data to arrive (either raw or from a decompressor) before it
can process the chunk. But 32kb still feels like a small buffer to
have to wait for. And in many cases, the client will convert from
8 read(4096) to 1 read(32768). That's happening in Python land. So
we cut down on the number of Python objects and function calls,
making the client faster as well. I don't think there are any
significant concerns to increasing the payload chunk size to 32kb.
The impact of this change on performance significant. Using `curl`
to obtain a stream clone bundle2 payload from a server on localhost
serving the mozilla-unified repository:
before: 20.78 user; 7.71 system; 80.5 MB/s
after: 13.90 user; 3.51 system; 132 MB/s
legacy: 9.72 user; 8.16 system; 132 MB/s
bundle2 stream clone generation is still more resource intensive than
legacy stream clone (that's likely because of the use of a
util.chunkbuffer). But the throughput is the same. We might
be in territory we're this is effectively a benchmark of the
networking stack or Python's syscall throughput.
From the client perspective, `hg clone -U --stream`:
before: 33.50 user; 7.95 system; 53.3 MB/s
after: 22.82 user; 7.33 system; 72.7 MB/s
legacy: 29.96 user; 7.94 system; 58.0 MB/s
And for `hg clone --stream` with a working directory update of
~230k files:
after: 119.55 user; 26.47 system; 0:57.08 wall
legacy: 126.98 user; 26.94 system; 1:05.56 wall
So, it appears that bundle2's stream clone is now definitively faster
than legacy stream clone!
Differential Revision: https://phab.mercurial-scm.org/D1932
#require mtn
Monotone directory is called .monotone on *nix and monotone
on Windows.
#if windows
$ mtndir=monotone
#else
$ mtndir=.monotone
#endif
$ echo "[extensions]" >> $HGRCPATH
$ echo "convert=" >> $HGRCPATH
Windows version of monotone home
$ APPDATA=$HOME; export APPDATA
tedious monotone keys configuration
The /dev/null redirection is necessary under Windows, or
it complains about home directory permissions
$ mtn --quiet genkey test@selenic.com 1>/dev/null 2>&1 <<EOF
> passphrase
> passphrase
> EOF
$ cat >> $HOME/$mtndir/monotonerc <<EOF
> function get_passphrase(keypair_id)
> return "passphrase"
> end
> EOF
create monotone repository
$ mtn db init --db=repo.mtn
$ mtn --db=repo.mtn --branch=com.selenic.test setup workingdir
$ cd workingdir
$ echo a > a
$ mkdir dir
$ echo b > dir/b
$ echo d > dir/d
$ $PYTHON -c 'file("bin", "wb").write("a\\x00b")'
$ echo c > c
$ mtn add a dir/b dir/d c bin
mtn: adding 'a' to workspace manifest
mtn: adding 'bin' to workspace manifest
mtn: adding 'c' to workspace manifest
mtn: adding 'dir' to workspace manifest
mtn: adding 'dir/b' to workspace manifest
mtn: adding 'dir/d' to workspace manifest
$ mtn ci -m initialize
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 0f6e5e4f2e7d2a8ef312408f57618abf026afd90
update monotone working directory
$ mtn mv a dir/a
mtn: skipping 'dir', already accounted for in workspace
mtn: renaming 'a' to 'dir/a' in workspace manifest
$ echo a >> dir/a
$ echo b >> dir/b
$ mtn drop c
mtn: dropping 'c' from workspace manifest
$ $PYTHON -c 'file("bin", "wb").write("b\\x00c")'
$ mtn ci -m update1
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 51d0a982464573a2a2cf5ee2c9219c652aaebeff
$ cd ..
convert once
$ hg convert -s mtn repo.mtn
assuming destination repo.mtn-hg
initializing destination repo.mtn-hg repository
scanning source...
sorting...
converting...
1 initialize
0 update1
$ cd workingdir
$ echo e > e
$ mtn add e
mtn: adding 'e' to workspace manifest
$ mtn drop dir/b
mtn: dropping 'dir/b' from workspace manifest
$ mtn mv bin bin2
mtn: renaming 'bin' to 'bin2' in workspace manifest
$ mtn ci -m 'update2 "with" quotes'
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision ebe58335d85d8cb176b6d0a12be04f5314b998da
test directory move
$ mkdir -p dir1/subdir1
$ mkdir -p dir1/subdir2_other
$ echo file1 > dir1/subdir1/file1
$ echo file2 > dir1/subdir2_other/file1
$ mtn add dir1/subdir1/file1 dir1/subdir2_other/file1
mtn: adding 'dir1' to workspace manifest
mtn: adding 'dir1/subdir1' to workspace manifest
mtn: adding 'dir1/subdir1/file1' to workspace manifest
mtn: adding 'dir1/subdir2_other' to workspace manifest
mtn: adding 'dir1/subdir2_other/file1' to workspace manifest
$ mtn ci -m createdir1
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision a8d62bc04fee4d2936d28e98bbcc81686dd74306
$ mtn rename dir1/subdir1 dir1/subdir2
mtn: skipping 'dir1', already accounted for in workspace
mtn: renaming 'dir1/subdir1' to 'dir1/subdir2' in workspace manifest
$ mtn ci -m movedir1
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 2c3d241bbbfe538b1b51d910f5676407e3f4d3a6
test subdirectory move
$ mtn mv dir dir2
mtn: renaming 'dir' to 'dir2' in workspace manifest
$ echo newfile > dir2/newfile
$ mtn drop dir2/d
mtn: dropping 'dir2/d' from workspace manifest
$ mtn add dir2/newfile
mtn: adding 'dir2/newfile' to workspace manifest
$ mtn ci -m movedir
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision fdb5a02dae8bfce3a79b3393680af471016e1b4c
Test directory removal with empty directory
$ mkdir dir2/dir
$ mkdir dir2/dir/subdir
$ echo f > dir2/dir/subdir/f
$ mkdir dir2/dir/emptydir
$ mtn add --quiet -R dir2/dir
$ mtn ci -m emptydir
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 8bbf76d717001d24964e4604739fdcd0f539fc88
$ mtn drop -R dir2/dir
mtn: dropping 'dir2/dir/subdir/f' from workspace manifest
mtn: dropping 'dir2/dir/subdir' from workspace manifest
mtn: dropping 'dir2/dir/emptydir' from workspace manifest
mtn: dropping 'dir2/dir' from workspace manifest
$ mtn ci -m dropdirectory
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 2323d4bc324e6c82628dc04d47a9fd32ad24e322
test directory and file move
$ mkdir -p dir3/d1
$ echo a > dir3/a
$ mtn add dir3/a dir3/d1
mtn: adding 'dir3' to workspace manifest
mtn: adding 'dir3/a' to workspace manifest
mtn: adding 'dir3/d1' to workspace manifest
$ mtn ci -m dirfilemove
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 47b192f720faa622f48c68d1eb075b26d405aa8b
$ mtn mv dir3/a dir3/d1/a
mtn: skipping 'dir3/d1', already accounted for in workspace
mtn: renaming 'dir3/a' to 'dir3/d1/a' in workspace manifest
$ mtn mv dir3/d1 dir3/d2
mtn: skipping 'dir3', already accounted for in workspace
mtn: renaming 'dir3/d1' to 'dir3/d2' in workspace manifest
$ mtn ci -m dirfilemove2
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 8b543a400d3ee7f6d4bb1835b9b9e3747c8cb632
test directory move into another directory move
$ mkdir dir4
$ mkdir dir5
$ echo a > dir4/a
$ mtn add dir4/a dir5
mtn: adding 'dir4' to workspace manifest
mtn: adding 'dir4/a' to workspace manifest
mtn: adding 'dir5' to workspace manifest
$ mtn ci -m dirdirmove
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 466e0b2afc7a55aa2b4ab2f57cb240bb6cd66fc7
$ mtn mv dir5 dir6
mtn: renaming 'dir5' to 'dir6' in workspace manifest
$ mtn mv dir4 dir6/dir4
mtn: skipping 'dir6', already accounted for in workspace
mtn: renaming 'dir4' to 'dir6/dir4' in workspace manifest
$ mtn ci -m dirdirmove2
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 3d1f77ebad0c23a5d14911be3b670f990991b749
test diverging directory moves
$ mkdir -p dir7/dir9/dir8
$ echo a > dir7/dir9/dir8/a
$ echo b > dir7/dir9/b
$ echo c > dir7/c
$ mtn add -R dir7
mtn: adding 'dir7' to workspace manifest
mtn: adding 'dir7/c' to workspace manifest
mtn: adding 'dir7/dir9' to workspace manifest
mtn: adding 'dir7/dir9/b' to workspace manifest
mtn: adding 'dir7/dir9/dir8' to workspace manifest
mtn: adding 'dir7/dir9/dir8/a' to workspace manifest
$ mtn ci -m divergentdirmove
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 08a08511f18b428d840199b062de90d0396bc2ed
$ mtn mv dir7 dir7-2
mtn: renaming 'dir7' to 'dir7-2' in workspace manifest
$ mtn mv dir7-2/dir9 dir9-2
mtn: renaming 'dir7-2/dir9' to 'dir9-2' in workspace manifest
$ mtn mv dir9-2/dir8 dir8-2
mtn: renaming 'dir9-2/dir8' to 'dir8-2' in workspace manifest
$ mtn ci -m divergentdirmove2
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision 4a736634505795f17786fffdf2c9cbf5b11df6f6
test large file support (> 32kB)
>>> fp = file('large-file', 'wb')
>>> for x in xrange(10000): fp.write('%d\n' % x)
>>> fp.close()
$ md5sum.py large-file
5d6de8a95c3b6bf9e0ffb808ba5299c1 large-file
$ mtn add large-file
mtn: adding 'large-file' to workspace manifest
$ mtn ci -m largefile
mtn: beginning commit on branch 'com.selenic.test'
mtn: committed revision f0a20fecd10dc4392d18fe69a03f1f4919d3387b
test suspending (closing a branch)
$ mtn suspend f0a20fecd10dc4392d18fe69a03f1f4919d3387b 2> /dev/null
$ cd ..
convert incrementally
$ hg convert -s mtn repo.mtn
assuming destination repo.mtn-hg
scanning source...
sorting...
converting...
12 update2 "with" quotes
11 createdir1
10 movedir1
9 movedir
8 emptydir
7 dropdirectory
6 dirfilemove
5 dirfilemove2
4 dirdirmove
3 dirdirmove2
2 divergentdirmove
1 divergentdirmove2
0 largefile
$ glog()
> {
> hg log -G --template '{rev} "{desc|firstline}" files: {files}\n' "$@"
> }
$ cd repo.mtn-hg
$ hg up -C
12 files updated, 0 files merged, 0 files removed, 0 files unresolved
no open descendant heads on branch "com.selenic.test", updating to a closed head
(committing will reopen branch "com.selenic.test")
$ glog
@ 14 "largefile" files: large-file
|
o 13 "divergentdirmove2" files: dir7-2/c dir7/c dir7/dir9/b dir7/dir9/dir8/a dir8-2/a dir9-2/b
|
o 12 "divergentdirmove" files: dir7/c dir7/dir9/b dir7/dir9/dir8/a
|
o 11 "dirdirmove2" files: dir4/a dir6/dir4/a
|
o 10 "dirdirmove" files: dir4/a
|
o 9 "dirfilemove2" files: dir3/a dir3/d2/a
|
o 8 "dirfilemove" files: dir3/a
|
o 7 "dropdirectory" files: dir2/dir/subdir/f
|
o 6 "emptydir" files: dir2/dir/subdir/f
|
o 5 "movedir" files: dir/a dir/d dir2/a dir2/newfile
|
o 4 "movedir1" files: dir1/subdir1/file1 dir1/subdir2/file1
|
o 3 "createdir1" files: dir1/subdir1/file1 dir1/subdir2_other/file1
|
o 2 "update2 "with" quotes" files: bin bin2 dir/b e
|
o 1 "update1" files: a bin c dir/a dir/b
|
o 0 "initialize" files: a bin c dir/b dir/d
manifest
$ hg manifest
bin2
dir1/subdir2/file1
dir1/subdir2_other/file1
dir2/a
dir2/newfile
dir3/d2/a
dir6/dir4/a
dir7-2/c
dir8-2/a
dir9-2/b
e
large-file
contents
$ cat dir2/a
a
a
$ test -d dir2/dir && echo 'removed dir2/dir is still there!'
[1]
file move
$ hg log -v -C -r 1 | grep copies
copies: dir/a (a)
check directory move
$ hg manifest -r 4
bin2
dir/a
dir/d
dir1/subdir2/file1
dir1/subdir2_other/file1
e
$ test -d dir1/subdir2 || echo 'new dir1/subdir2 does not exist!'
$ test -d dir1/subdir1 && echo 'renamed dir1/subdir1 is still there!'
[1]
$ hg log -v -C -r 4 | grep copies
copies: dir1/subdir2/file1 (dir1/subdir1/file1)
check file remove with directory move
$ hg manifest -r 5
bin2
dir1/subdir2/file1
dir1/subdir2_other/file1
dir2/a
dir2/newfile
e
check file move with directory move
$ hg manifest -r 9
bin2
dir1/subdir2/file1
dir1/subdir2_other/file1
dir2/a
dir2/newfile
dir3/d2/a
e
check file directory directory move
$ hg manifest -r 11
bin2
dir1/subdir2/file1
dir1/subdir2_other/file1
dir2/a
dir2/newfile
dir3/d2/a
dir6/dir4/a
e
check divergent directory moves
$ hg manifest -r 13
bin2
dir1/subdir2/file1
dir1/subdir2_other/file1
dir2/a
dir2/newfile
dir3/d2/a
dir6/dir4/a
dir7-2/c
dir8-2/a
dir9-2/b
e
test large file support (> 32kB)
$ md5sum.py large-file
5d6de8a95c3b6bf9e0ffb808ba5299c1 large-file
check branch closing
$ hg branches -a
$ hg branches -c
com.selenic.test 14:* (closed) (glob)