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.
$ cat >> $HGRCPATH <<EOF
> [extensions]
> rebase=
> mq=
>
> [phases]
> publish=False
>
> [alias]
> tglog = log -G --template "{rev}: '{desc}' {branches}\n"
> theads = heads --template "{rev}: '{desc}' {branches}\n"
> EOF
$ hg init a
$ cd a
$ echo a > a
$ hg ci -Am A
adding a
$ hg branch branch1
marked working directory as branch branch1
(branches are permanent and global, did you want a bookmark?)
$ hg ci -m 'branch1'
$ echo b > b
$ hg ci -Am B
adding b
$ hg up -q 0
$ hg branch branch2
marked working directory as branch branch2
$ hg ci -m 'branch2'
$ echo c > C
$ hg ci -Am C
adding C
$ hg up -q 2
$ hg branch -f branch2
marked working directory as branch branch2
$ echo d > d
$ hg ci -Am D
adding d
created new head
$ echo e > e
$ hg ci -Am E
adding e
$ hg update default
0 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ hg branch branch3
marked working directory as branch branch3
$ hg ci -m 'branch3'
$ echo f > f
$ hg ci -Am F
adding f
$ cd ..
Rebase part of branch2 (5-6) onto branch3 (8):
$ hg clone -q -u . a a1
$ cd a1
$ hg tglog
@ 8: 'F' branch3
|
o 7: 'branch3' branch3
|
| o 6: 'E' branch2
| |
| o 5: 'D' branch2
| |
| | o 4: 'C' branch2
| | |
+---o 3: 'branch2' branch2
| |
| o 2: 'B' branch1
| |
| o 1: 'branch1' branch1
|/
o 0: 'A'
$ hg branches
branch3 8:4666b71e8e32
branch2 6:5097051d331d
branch1 2:0a03079c47fd (inactive)
default 0:1994f17a630e (inactive)
$ hg theads
8: 'F' branch3
6: 'E' branch2
4: 'C' branch2
2: 'B' branch1
0: 'A'
$ hg rebase -s 5 -d 8
rebasing 5:635859577d0b "D"
rebasing 6:5097051d331d "E"
saved backup bundle to $TESTTMP/a1/.hg/strip-backup/635859577d0b-89160bff-backup.hg (glob)
$ hg branches
branch3 8:466cdfb14b62
branch2 4:e4fdb121d036
branch1 2:0a03079c47fd
default 0:1994f17a630e (inactive)
$ hg theads
8: 'E' branch3
4: 'C' branch2
2: 'B' branch1
0: 'A'
$ hg tglog
o 8: 'E' branch3
|
o 7: 'D' branch3
|
@ 6: 'F' branch3
|
o 5: 'branch3' branch3
|
| o 4: 'C' branch2
| |
| o 3: 'branch2' branch2
|/
| o 2: 'B' branch1
| |
| o 1: 'branch1' branch1
|/
o 0: 'A'
$ cd ..
Rebase head of branch3 (8) onto branch2 (6):
$ hg clone -q -u . a a2
$ cd a2
$ hg tglog
@ 8: 'F' branch3
|
o 7: 'branch3' branch3
|
| o 6: 'E' branch2
| |
| o 5: 'D' branch2
| |
| | o 4: 'C' branch2
| | |
+---o 3: 'branch2' branch2
| |
| o 2: 'B' branch1
| |
| o 1: 'branch1' branch1
|/
o 0: 'A'
$ hg rebase -s 8 -d 6
rebasing 8:4666b71e8e32 "F" (tip)
saved backup bundle to $TESTTMP/a2/.hg/strip-backup/4666b71e8e32-fc1c4e96-backup.hg (glob)
$ hg branches
branch2 8:6b4bdc1b5ac0
branch3 7:653b9feb4616
branch1 2:0a03079c47fd (inactive)
default 0:1994f17a630e (inactive)
$ hg theads
8: 'F' branch2
7: 'branch3' branch3
4: 'C' branch2
2: 'B' branch1
0: 'A'
$ hg tglog
@ 8: 'F' branch2
|
| o 7: 'branch3' branch3
| |
o | 6: 'E' branch2
| |
o | 5: 'D' branch2
| |
| | o 4: 'C' branch2
| | |
| | o 3: 'branch2' branch2
| |/
o | 2: 'B' branch1
| |
o | 1: 'branch1' branch1
|/
o 0: 'A'
$ hg verify -q
$ cd ..
Rebase entire branch3 (7-8) onto branch2 (6):
$ hg clone -q -u . a a3
$ cd a3
$ hg tglog
@ 8: 'F' branch3
|
o 7: 'branch3' branch3
|
| o 6: 'E' branch2
| |
| o 5: 'D' branch2
| |
| | o 4: 'C' branch2
| | |
+---o 3: 'branch2' branch2
| |
| o 2: 'B' branch1
| |
| o 1: 'branch1' branch1
|/
o 0: 'A'
$ hg rebase -s 7 -d 6
rebasing 7:653b9feb4616 "branch3"
note: rebase of 7:653b9feb4616 created no changes to commit
rebasing 8:4666b71e8e32 "F" (tip)
saved backup bundle to $TESTTMP/a3/.hg/strip-backup/653b9feb4616-3c88de16-backup.hg (glob)
$ hg branches
branch2 7:6b4bdc1b5ac0
branch1 2:0a03079c47fd (inactive)
default 0:1994f17a630e (inactive)
$ hg theads
7: 'F' branch2
4: 'C' branch2
2: 'B' branch1
0: 'A'
$ hg tglog
@ 7: 'F' branch2
|
o 6: 'E' branch2
|
o 5: 'D' branch2
|
| o 4: 'C' branch2
| |
| o 3: 'branch2' branch2
| |
o | 2: 'B' branch1
| |
o | 1: 'branch1' branch1
|/
o 0: 'A'
$ hg verify -q
Stripping multiple branches in one go bypasses the fast-case code to
update the branch cache.
$ hg strip 2
0 files updated, 0 files merged, 4 files removed, 0 files unresolved
saved backup bundle to $TESTTMP/a3/.hg/strip-backup/0a03079c47fd-11b7c407-backup.hg (glob)
$ hg tglog
o 3: 'C' branch2
|
o 2: 'branch2' branch2
|
| @ 1: 'branch1' branch1
|/
o 0: 'A'
$ hg branches
branch2 3:e4fdb121d036
branch1 1:63379ac49655
default 0:1994f17a630e (inactive)
$ hg theads
3: 'C' branch2
1: 'branch1' branch1
0: 'A'
Fast path branchcache code should not be invoked if branches stripped is not
the same as branches remaining.
$ hg init b
$ cd b
$ hg branch branch1
marked working directory as branch branch1
(branches are permanent and global, did you want a bookmark?)
$ hg ci -m 'branch1'
$ hg branch branch2
marked working directory as branch branch2
$ hg ci -m 'branch2'
$ hg branch -f branch1
marked working directory as branch branch1
$ echo a > A
$ hg ci -Am A
adding A
created new head
$ hg tglog
@ 2: 'A' branch1
|
o 1: 'branch2' branch2
|
o 0: 'branch1' branch1
$ hg theads
2: 'A' branch1
1: 'branch2' branch2
$ hg strip 2
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
saved backup bundle to $TESTTMP/a3/b/.hg/strip-backup/a5b4b27ed7b4-a3b6984e-backup.hg (glob)
$ hg theads
1: 'branch2' branch2
0: 'branch1' branch1
Make sure requesting to strip a revision already stripped does not confuse things.
Try both orders.
$ cd ..
$ hg init c
$ cd c
$ echo a > a
$ hg ci -Am A
adding a
$ echo b > b
$ hg ci -Am B
adding b
$ echo c > c
$ hg ci -Am C
adding c
$ echo d > d
$ hg ci -Am D
adding d
$ echo e > e
$ hg ci -Am E
adding e
$ hg tglog
@ 4: 'E'
|
o 3: 'D'
|
o 2: 'C'
|
o 1: 'B'
|
o 0: 'A'
$ hg strip 3 4
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
saved backup bundle to $TESTTMP/a3/c/.hg/strip-backup/67a385d4e6f2-b9243789-backup.hg (glob)
$ hg theads
2: 'C'
$ hg strip 2 1
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
saved backup bundle to $TESTTMP/a3/c/.hg/strip-backup/6c81ed0049f8-a687065f-backup.hg (glob)
$ hg theads
0: 'A'
Make sure rebase does not break for phase/filter related reason
----------------------------------------------------------------
(issue3858)
$ cd ..
$ cat >> $HGRCPATH << EOF
> [ui]
> logtemplate={rev} {desc} {phase}\n
> EOF
$ hg init c4
$ cd c4
$ echo a > a
$ hg ci -Am A
adding a
$ echo b > b
$ hg ci -Am B
adding b
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo c > c
$ hg ci -Am C
adding c
created new head
$ hg up 1
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m d
$ hg up 2
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo e > e
$ hg ci -Am E
adding e
created new head
$ hg merge 3
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m F
$ hg up 3
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo g > g
$ hg ci -Am G
adding g
created new head
$ echo h > h
$ hg ci -Am H
adding h
$ hg up 5
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ echo i > i
$ hg ci -Am I
adding i
Turn most changeset public
$ hg ph -p 7
$ hg heads
8 I draft
7 H public
$ hg log -G
@ 8 I draft
|
| o 7 H public
| |
| o 6 G public
| |
o | 5 F draft
|\|
o | 4 E draft
| |
| o 3 d public
|/|
o | 2 C public
| |
| o 1 B public
|/
o 0 A public
$ cat > $TESTTMP/checkeditform.sh <<EOF
> env | grep HGEDITFORM
> true
> EOF
$ HGEDITOR="sh $TESTTMP/checkeditform.sh" hg rebase --dest 7 --source 5 -e
rebasing 5:361a99976cc9 "F"
HGEDITFORM=rebase.merge
rebasing 8:326cfedc031c "I" (tip)
HGEDITFORM=rebase.normal
saved backup bundle to $TESTTMP/a3/c4/.hg/strip-backup/361a99976cc9-35e980d0-backup.hg (glob)