Mercurial > hg
view tests/test-debugbuilddag.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 | 95f490136e75 |
children | 8d6109b49b31 |
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plain $ hg init $ hg debugbuilddag '+2:f +3:p2 @temp <f+4 @default /p2 +2' \ > --config extensions.progress= --config progress.assume-tty=1 \ > --config progress.delay=0 --config progress.refresh=0 \ > --config progress.format=topic,bar,number \ > --config progress.width=60 \r (no-eol) (esc) building [ ] 0/12\r (no-eol) (esc) building [ ] 0/12\r (no-eol) (esc) building [==> ] 1/12\r (no-eol) (esc) building [==> ] 1/12\r (no-eol) (esc) building [======> ] 2/12\r (no-eol) (esc) building [=========> ] 3/12\r (no-eol) (esc) building [=============> ] 4/12\r (no-eol) (esc) building [=============> ] 4/12\r (no-eol) (esc) building [=============> ] 4/12\r (no-eol) (esc) building [================> ] 5/12\r (no-eol) (esc) building [====================> ] 6/12\r (no-eol) (esc) building [=======================> ] 7/12\r (no-eol) (esc) building [===========================> ] 8/12\r (no-eol) (esc) building [===========================> ] 8/12\r (no-eol) (esc) building [==============================> ] 9/12\r (no-eol) (esc) building [==================================> ] 10/12\r (no-eol) (esc) building [=====================================> ] 11/12\r (no-eol) (esc) \r (no-eol) (esc) tags $ cat .hg/localtags 66f7d451a68b85ed82ff5fcc254daf50c74144bd f bebd167eb94d257ace0e814aeb98e6972ed2970d p2 dag $ hg debugdag -t -b +2:f +3:p2 @temp*f+3 @default*/p2+2:tip tip $ hg id 000000000000 glog $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n' o 11: r11 [] @ 11.00 | o 10: r10 [] @ 10.00 | o 9: r9 [] @ 9.00 |\ | o 8: r8 [temp] @ 8.00 | | | o 7: r7 [temp] @ 7.00 | | | o 6: r6 [temp] @ 6.00 | | | o 5: r5 [temp] @ 5.00 | | o | 4: r4 [] @ 4.00 | | o | 3: r3 [] @ 3.00 | | o | 2: r2 [] @ 2.00 |/ o 1: r1 [] @ 1.00 | o 0: r0 [] @ 0.00 overwritten files, starting on a non-default branch $ rm -r .hg $ hg init $ hg debugbuilddag '@start.@default.:f +3:p2 @temp <f+4 @default /p2 +2' -q -o tags $ cat .hg/localtags f778700ebd50fcf282b23a4446bd155da6453eb6 f bbccf169769006e2490efd2a02f11c3d38d462bd p2 dag $ hg debugdag -t -b @start+1 @default+1:f +3:p2 @temp*f+3 @default*/p2+2:tip tip $ hg id 000000000000 glog $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n' o 11: r11 [] @ 11.00 | o 10: r10 [] @ 10.00 | o 9: r9 [] @ 9.00 |\ | o 8: r8 [temp] @ 8.00 | | | o 7: r7 [temp] @ 7.00 | | | o 6: r6 [temp] @ 6.00 | | | o 5: r5 [temp] @ 5.00 | | o | 4: r4 [] @ 4.00 | | o | 3: r3 [] @ 3.00 | | o | 2: r2 [] @ 2.00 |/ o 1: r1 [] @ 1.00 | o 0: r0 [start] @ 0.00 glog of $ hg log -G --template '{rev}: {desc} [{branches}]\n' of o 11: r11 [] | o 10: r10 [] | o 9: r9 [] |\ | o 8: r8 [temp] | | | o 7: r7 [temp] | | | o 6: r6 [temp] | | | o 5: r5 [temp] | | o | 4: r4 [] | | o | 3: r3 [] | | o | 2: r2 [] |/ o 1: r1 [] | o 0: r0 [start] tags $ hg tags -v tip 11:9ffe238a67a2 p2 4:bbccf1697690 local f 1:f778700ebd50 local cat of $ hg cat of --rev tip r11 new and mergeable files $ rm -r .hg $ hg init $ hg debugbuilddag '+2:f +3:p2 @temp <f+4 @default /p2 +2' -q -mn dag $ hg debugdag -t -b +2:f +3:p2 @temp*f+3 @default*/p2+2:tip tip $ hg id 000000000000 glog $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n' o 11: r11 [] @ 11.00 | o 10: r10 [] @ 10.00 | o 9: r9 [] @ 9.00 |\ | o 8: r8 [temp] @ 8.00 | | | o 7: r7 [temp] @ 7.00 | | | o 6: r6 [temp] @ 6.00 | | | o 5: r5 [temp] @ 5.00 | | o | 4: r4 [] @ 4.00 | | o | 3: r3 [] @ 3.00 | | o | 2: r2 [] @ 2.00 |/ o 1: r1 [] @ 1.00 | o 0: r0 [] @ 0.00 glog mf $ hg log -G --template '{rev}: {desc} [{branches}]\n' mf o 11: r11 [] | o 10: r10 [] | o 9: r9 [] |\ | o 8: r8 [temp] | | | o 7: r7 [temp] | | | o 6: r6 [temp] | | | o 5: r5 [temp] | | o | 4: r4 [] | | o | 3: r3 [] | | o | 2: r2 [] |/ o 1: r1 [] | o 0: r0 [] man r4 $ hg manifest -r4 mf nf0 nf1 nf2 nf3 nf4 cat r4 mf $ hg cat -r4 mf 0 r0 1 2 r1 3 4 r2 5 6 r3 7 8 r4 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 man r8 $ hg manifest -r8 mf nf0 nf1 nf5 nf6 nf7 nf8 cat r8 mf $ hg cat -r8 mf 0 r0 1 2 r1 3 4 5 6 7 8 9 10 r5 11 12 r6 13 14 r7 15 16 r8 17 18 19 20 21 22 23 man $ hg manifest --rev tip mf nf0 nf1 nf10 nf11 nf2 nf3 nf4 nf5 nf6 nf7 nf8 nf9 cat mf $ hg cat mf --rev tip 0 r0 1 2 r1 3 4 r2 5 6 r3 7 8 r4 9 10 r5 11 12 r6 13 14 r7 15 16 r8 17 18 r9 19 20 r10 21 22 r11 23