stream-clone: disable gc for the initial section for the v3 format
The number of small container created turn Python in a gc-frenzy that seriously
impact performance.
This significantly boost performance. The following number comes from a large
private repository using perf::stream-locked-section:
base-line: 35.04 seconds
prev-change: 24.51 seconds (-30%)
prev-change: 20.88 seconds (-40%)
this-change: 14.22 seconds (-60% from baseline; -31% from prev)
This test cover a bug that no longer exist.
Define helpers.
$ hg_log () { hg log -G -T "{rev}:{node|short}"; }
$ commit () { echo "foo - ${2:-$1}" > $1; hg commit -Aqm "Edited $1"; }
$ strip() { hg --config extensions.strip= strip -q -r "$1" ; }
Setup hg repo.
$ hg init repo
$ cd repo
$ touch x; hg add x; hg commit -m "initial"
$ hg clone -q . ../clone
$ commit a
$ cd ../clone
$ commit b
$ hg pull -q ../repo
$ ls -1 .hg/cache/branch?*
.hg/cache/branch2-base
.hg/cache/branch2-served
$ cat .hg/cache/branch?-served
222ae9789a75703f9836e44de7db179cbfd420ee 2
a3498d6e39376d2456425dd8c692367bdbf00fa2 o default
222ae9789a75703f9836e44de7db179cbfd420ee o default
$ hg_log
o 2:222ae9789a75
|
| @ 1:a3498d6e3937
|/
o 0:7ab0a3bd758a
$ strip '1:'
After the strip the "served" cache is now identical to the "base" one, and the
older one have been actively deleted.
$ ls -1 .hg/cache/branch?*
.hg/cache/branch2-base
$ cat .hg/cache/branch?-base
7ab0a3bd758a58b9f79557ce708533e627776cce 0
7ab0a3bd758a58b9f79557ce708533e627776cce o default
We do a new commit and we get a new valid branchmap for the served version
$ commit c
$ ls -1 .hg/cache/branch?*
.hg/cache/branch2-base
.hg/cache/branch2-served
$ cat .hg/cache/branch?-served
a1602b357cfca067600406eb19060c7128804d72 1
a1602b357cfca067600406eb19060c7128804d72 o default
On pull we end up with the same tip, and so wrongly reuse the invalid cache and crash.
$ hg pull ../repo --quiet
$ hg heads -T '{rev} {node} {branch}\n'
2 222ae9789a75703f9836e44de7db179cbfd420ee default
1 a1602b357cfca067600406eb19060c7128804d72 default
$ ls -1 .hg/cache/branch?*
.hg/cache/branch2-base
.hg/cache/branch2-served
$ cat .hg/cache/branch?-served
222ae9789a75703f9836e44de7db179cbfd420ee 2
a1602b357cfca067600406eb19060c7128804d72 o default
222ae9789a75703f9836e44de7db179cbfd420ee o default