Mercurial > hg
view tests/test-tools.t @ 30212:260af19891f2
changegroup: increase write buffer size to 128k
By default, Python defers to the operating system for choosing the
default buffer size on opened files. On my Linux machine, the default
is 4k, which is really small for 2016.
This patch bumps the write buffer size when writing
changegroups/bundles to 128k. This matches the 128k read buffer
we already use on revlogs.
It's worth noting that this only impacts when writing to an explicit
file (such as during `hg bundle`). Buffers when writing to bundle
files via the repo vfs or to a temporary file are not impacted.
When producing a none-v2 bundle file of the mozilla-unified repository,
this change caused the number of write() system calls to drop from
952,449 to 29,788. After this change, the most frequent system
calls are fstat(), read(), lseek(), and open(). There were
2,523,672 system calls after this patch (so a net decrease of
~950k is statistically significant).
This change shows no performance change on my system. But I have a
high-end system with a fast SSD. It is quite possible this change
will have a significant impact on network file systems, where
extra network round trips due to excessive I/O system calls could
introduce significant latency.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 16 Oct 2016 13:35:23 -0700 |
parents | 6686ae524f94 |
children | 75be14993fda |
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Tests of the file helper tool $ f -h ?sage: f [options] [filenames] (glob) ?ptions: (glob) -h, --help show this help message and exit -t, --type show file type (file or directory) -m, --mode show file mode -l, --links show number of links -s, --size show size of file -n NEWER, --newer=NEWER check if file is newer (or same) -r, --recurse recurse into directories -S, --sha1 show sha1 hash of the content -M, --md5 show md5 hash of the content -D, --dump dump file content -H, --hexdump hexdump file content -B BYTES, --bytes=BYTES number of characters to dump -L LINES, --lines=LINES number of lines to dump -q, --quiet no default output $ mkdir dir $ cd dir $ f --size size=0 $ echo hello | f --md5 --size size=6, md5=b1946ac92492d2347c6235b4d2611184 $ f foo foo: file not found $ echo foo > foo $ f foo foo: #if symlink $ f foo --mode foo: mode=644 #endif #if no-windows $ python $TESTDIR/seq.py 10 > bar #else Convert CRLF -> LF for consistency $ python $TESTDIR/seq.py 10 | sed "s/$//" > bar #endif #if unix-permissions symlink $ chmod +x bar $ f bar --newer foo --mode --type --size --dump --links --bytes 7 bar: file, size=21, mode=755, links=1, newer than foo >>> 1 2 3 4 <<< no trailing newline #endif #if unix-permissions $ ln bar baz $ f bar -n baz -l --hexdump -t --sha1 --lines=9 -B 20 bar: file, links=2, newer than baz, sha1=612ca68d0305c821750a 0000: 31 0a 32 0a 33 0a 34 0a 35 0a 36 0a 37 0a 38 0a |1.2.3.4.5.6.7.8.| 0010: 39 0a |9.| $ rm baz #endif #if unix-permissions symlink $ ln -s yadda l $ f . --recurse -MStmsB4 .: directory with 3 files, mode=755 ./bar: file, size=21, mode=755, md5=3b03, sha1=612c ./foo: file, size=4, mode=644, md5=d3b0, sha1=f1d2 ./l: link, size=5, md5=2faa, sha1=af93 #endif $ f --quiet bar -DL 3 1 2 3 $ cd .. Yadda is a symlink #if symlink $ f -qr dir -HB 17 dir: directory with 3 files dir/bar: 0000: 31 0a 32 0a 33 0a 34 0a 35 0a 36 0a 37 0a 38 0a |1.2.3.4.5.6.7.8.| 0010: 39 |9| dir/foo: 0000: 66 6f 6f 0a |foo.| dir/l: 0000: 79 61 64 64 61 |yadda| #else $ f -qr dir -HB 17 dir: directory with 2 files (esc) dir/bar: (glob) 0000: 31 0a 32 0a 33 0a 34 0a 35 0a 36 0a 37 0a 38 0a |1.2.3.4.5.6.7.8.| 0010: 39 |9| dir/foo: (glob) 0000: 66 6f 6f 0a |foo.| #endif