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
This test file test the various messages when accessing obsolete
revisions.
Global setup
============
$ . $TESTDIR/testlib/obsmarker-common.sh
$ cat >> $HGRCPATH <<EOF
> [ui]
> interactive = true
> [phases]
> publish=False
> [experimental]
> evolution.createmarkers = yes
> evolution.effect-flags = yes
> EOF
Test output on amended commit
=============================
Test setup
----------
$ hg init $TESTTMP/local-amend
$ cd $TESTTMP/local-amend
$ mkcommit ROOT
$ mkcommit A0
$ echo 42 >> A0
$ hg commit --amend -m "A1
>
> Better commit message"
$ hg log --hidden -G
@ changeset: 2:4ae3a4151de9
| tag: tip
| parent: 0:ea207398892e
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A1
|
| x changeset: 1:471f378eab4c
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| obsolete: rewritten using amend as 2:4ae3a4151de9
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
Actual test
-----------
$ hg update 471f378eab4c
abort: hidden revision '471f378eab4c' was rewritten as: 4ae3a4151de9!
(use --hidden to access hidden revisions)
[255]
$ hg update --hidden "desc(A0)"
updating to a hidden changeset 471f378eab4c
(hidden revision '471f378eab4c' was rewritten as: 4ae3a4151de9)
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test output with pruned commit
==============================
Test setup
----------
$ hg init $TESTTMP/local-prune
$ cd $TESTTMP/local-prune
$ mkcommit ROOT
$ mkcommit A0 # 0
$ mkcommit B0 # 1
$ hg log --hidden -G
@ changeset: 2:0dec01379d3b
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: B0
|
o changeset: 1:471f378eab4c
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
$ hg debugobsolete --record-parents `getid 'desc(B0)'`
obsoleted 1 changesets
$ hg log --hidden -G
@ changeset: 2:0dec01379d3b
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| obsolete: pruned
| summary: B0
|
o changeset: 1:471f378eab4c
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
Actual test
-----------
$ hg up 1
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg up 0dec01379d3b
abort: hidden revision '0dec01379d3b' is pruned!
(use --hidden to access hidden revisions)
[255]
$ hg up --hidden -r 'desc(B0)'
updating to a hidden changeset 0dec01379d3b
(hidden revision '0dec01379d3b' is pruned)
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test output with splitted commit
================================
Test setup
----------
$ hg init $TESTTMP/local-split
$ cd $TESTTMP/local-split
$ mkcommit ROOT
$ echo 42 >> a
$ echo 43 >> b
$ hg commit -A -m "A0"
adding a
adding b
$ hg log --hidden -G
@ changeset: 1:471597cad322
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
# Simulate a split
$ hg up 0
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ echo 42 >> a
$ hg commit -A -m "A0"
adding a
created new head
$ echo 43 >> b
$ hg commit -A -m "A0"
adding b
$ hg debugobsolete `getid '1'` `getid '2'` `getid '3'`
obsoleted 1 changesets
$ hg log --hidden -G
@ changeset: 3:f257fde29c7a
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
o changeset: 2:337fec4d2edc
| parent: 0:ea207398892e
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
| x changeset: 1:471597cad322
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| obsolete: split as 2:337fec4d2edc, 3:f257fde29c7a
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
Actual test
-----------
$ hg update 471597cad322
abort: hidden revision '471597cad322' was split as: 337fec4d2edc, f257fde29c7a!
(use --hidden to access hidden revisions)
[255]
$ hg update --hidden 'min(desc(A0))'
updating to a hidden changeset 471597cad322
(hidden revision '471597cad322' was split as: 337fec4d2edc, f257fde29c7a)
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test output with lots of splitted commit
========================================
Test setup
----------
$ hg init $TESTTMP/local-lots-split
$ cd $TESTTMP/local-lots-split
$ mkcommit ROOT
$ echo 42 >> a
$ echo 43 >> b
$ echo 44 >> c
$ echo 45 >> d
$ hg commit -A -m "A0"
adding a
adding b
adding c
adding d
$ hg log --hidden -G
@ changeset: 1:de7290d8b885
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
# Simulate a split
$ hg up 0
0 files updated, 0 files merged, 4 files removed, 0 files unresolved
$ echo 42 >> a
$ hg commit -A -m "A0"
adding a
created new head
$ echo 43 >> b
$ hg commit -A -m "A0"
adding b
$ echo 44 >> c
$ hg commit -A -m "A0"
adding c
$ echo 45 >> d
$ hg commit -A -m "A0"
adding d
$ hg debugobsolete `getid '1'` `getid '2'` `getid '3'` `getid '4'` `getid '5'`
obsoleted 1 changesets
$ hg log --hidden -G
@ changeset: 5:c7f044602e9b
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
o changeset: 4:1ae8bc733a14
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
o changeset: 3:f257fde29c7a
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
o changeset: 2:337fec4d2edc
| parent: 0:ea207398892e
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
| x changeset: 1:de7290d8b885
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| obsolete: split as 2:337fec4d2edc, 3:f257fde29c7a, 4:1ae8bc733a14, 5:c7f044602e9b
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
Actual test
-----------
$ hg update de7290d8b885
abort: hidden revision 'de7290d8b885' was split as: 337fec4d2edc, f257fde29c7a and 2 more!
(use --hidden to access hidden revisions)
[255]
$ hg update --hidden 'min(desc(A0))'
updating to a hidden changeset de7290d8b885
(hidden revision 'de7290d8b885' was split as: 337fec4d2edc, f257fde29c7a and 2 more)
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test output with folded commit
==============================
Test setup
----------
$ hg init $TESTTMP/local-fold
$ cd $TESTTMP/local-fold
$ mkcommit ROOT
$ mkcommit A0
$ mkcommit B0
$ hg log --hidden -G
@ changeset: 2:0dec01379d3b
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: B0
|
o changeset: 1:471f378eab4c
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
# Simulate a fold
$ hg up 0
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ echo "A0" > A0
$ echo "B0" > B0
$ hg add A0 B0
$ hg commit -m "C0"
created new head
$ hg debugobsolete `getid 'desc(A0)'` `getid 'desc(C0)'`
obsoleted 1 changesets
1 new orphan changesets
$ hg debugobsolete `getid 'desc(B0)'` `getid 'desc(C0)'`
obsoleted 1 changesets
$ hg log --hidden -G
@ changeset: 3:eb5a0daa2192
| tag: tip
| parent: 0:ea207398892e
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: C0
|
| x changeset: 2:0dec01379d3b
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | obsolete: rewritten as 3:eb5a0daa2192
| | summary: B0
| |
| x changeset: 1:471f378eab4c
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| obsolete: rewritten as 3:eb5a0daa2192
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
Actual test
-----------
$ hg update 471f378eab4c
abort: hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192!
(use --hidden to access hidden revisions)
[255]
$ hg update --hidden 'desc(A0)'
updating to a hidden changeset 471f378eab4c
(hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192)
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg update 0dec01379d3b
abort: hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192!
(use --hidden to access hidden revisions)
[255]
$ hg update --hidden 'desc(B0)'
updating to a hidden changeset 0dec01379d3b
(hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192)
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test output with divergence
===========================
Test setup
----------
$ hg init $TESTTMP/local-divergence
$ cd $TESTTMP/local-divergence
$ mkcommit ROOT
$ mkcommit A0
$ hg commit --amend -m "A1"
$ hg log --hidden -G
@ changeset: 2:fdf9bde5129a
| tag: tip
| parent: 0:ea207398892e
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A1
|
| x changeset: 1:471f378eab4c
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| obsolete: rewritten using amend as 2:fdf9bde5129a
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
$ hg update --hidden 'desc(A0)'
updating to a hidden changeset 471f378eab4c
(hidden revision '471f378eab4c' was rewritten as: fdf9bde5129a)
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg commit --amend -m "A2"
2 new content-divergent changesets
$ hg log --hidden -G
@ changeset: 3:65b757b745b9
| tag: tip
| parent: 0:ea207398892e
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| instability: content-divergent
| summary: A2
|
| * changeset: 2:fdf9bde5129a
|/ parent: 0:ea207398892e
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| instability: content-divergent
| summary: A1
|
| x changeset: 1:471f378eab4c
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| obsolete: rewritten using amend as 2:fdf9bde5129a
| obsolete: rewritten using amend as 3:65b757b745b9
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
Actual test
-----------
$ hg update 471f378eab4c
abort: hidden revision '471f378eab4c' has diverged!
(use --hidden to access hidden revisions)
[255]
$ hg update --hidden 'desc(A0)'
updating to a hidden changeset 471f378eab4c
(hidden revision '471f378eab4c' has diverged)
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test output with amended + folded commit
========================================
Test setup
----------
$ hg init $TESTTMP/local-amend-fold
$ cd $TESTTMP/local-amend-fold
$ mkcommit ROOT
$ mkcommit A0
$ mkcommit B0
$ hg commit --amend -m "B1"
$ hg log --hidden -G
@ changeset: 3:b7ea6d14e664
| tag: tip
| parent: 1:471f378eab4c
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: B1
|
| x changeset: 2:0dec01379d3b
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| obsolete: rewritten using amend as 3:b7ea6d14e664
| summary: B0
|
o changeset: 1:471f378eab4c
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
# Simulate a fold
$ hg up 0
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ echo "A0" > A0
$ echo "B0" > B0
$ hg add A0 B0
$ hg commit -m "C0"
created new head
$ hg debugobsolete `getid 'desc(A0)'` `getid 'desc(C0)'`
obsoleted 1 changesets
1 new orphan changesets
$ hg debugobsolete `getid 'desc(B1)'` `getid 'desc(C0)'`
obsoleted 1 changesets
$ hg log --hidden -G
@ changeset: 4:eb5a0daa2192
| tag: tip
| parent: 0:ea207398892e
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: C0
|
| x changeset: 3:b7ea6d14e664
| | parent: 1:471f378eab4c
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | obsolete: rewritten as 4:eb5a0daa2192
| | summary: B1
| |
| | x changeset: 2:0dec01379d3b
| |/ user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | obsolete: rewritten using amend as 3:b7ea6d14e664
| | summary: B0
| |
| x changeset: 1:471f378eab4c
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| obsolete: rewritten as 4:eb5a0daa2192
| summary: A0
|
o changeset: 0:ea207398892e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: ROOT
Actual test
-----------
$ hg update 471f378eab4c
abort: hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192!
(use --hidden to access hidden revisions)
[255]
$ hg update --hidden 'desc(A0)'
updating to a hidden changeset 471f378eab4c
(hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192)
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg update --hidden 0dec01379d3b
updating to a hidden changeset 0dec01379d3b
(hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192)
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg update 0dec01379d3b
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg update --hidden 'desc(B0)'
0 files updated, 0 files merged, 0 files removed, 0 files unresolved