cborutil: change buffering strategy
Profiling revealed that we were spending a lot of time on the
line that was concatenating the old buffer with the incoming data
when attempting to decode long byte strings, such as manifest
revisions.
Essentially, we were feeding N chunks of size len(X) << len(Y) into
decode() and continuously allocating a new, larger buffer to hold
the undecoded input. This created substantial memory churn and
slowed down execution.
Changing the code to aggregate pending chunks in a list until we
have enough data to fully decode the next atom makes things much
more efficient.
I don't have exact data, but I recall the old code spending >1s
on manifest fulltexts from the mozilla-unified repo. The new code
doesn't significantly appear in profile output.
Differential Revision: https://phab.mercurial-scm.org/D4854
$ . "$TESTDIR/narrow-library.sh"
create full repo
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [narrow]
> serveellipses=True
> EOF
$ mkdir inside
$ echo 1 > inside/f
$ mkdir inside2
$ echo 1 > inside2/f
$ mkdir outside
$ echo 1 > outside/f
$ hg ci -Aqm 'initial'
$ echo 2 > inside/f
$ hg ci -qm 'inside 2'
$ echo 2 > inside2/f
$ hg ci -qm 'inside2 2'
$ echo 2 > outside/f
$ hg ci -qm 'outside 2'
$ cd ..
$ hg clone --narrow ssh://user@dummy/master narrow --include inside
requesting all changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 2 changes to 1 files
new changesets *:* (glob)
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg clone --narrow ssh://user@dummy/master narrow2 --include inside --include inside2
requesting all changes
adding changesets
adding manifests
adding file changes
added 4 changesets with 4 changes to 2 files
new changesets *:* (glob)
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
Can push to wider repo if change does not affect paths in wider repo that are
not also in narrower repo
$ cd narrow
$ echo 3 > inside/f
$ hg ci -m 'inside 3'
$ hg push ssh://user@dummy/narrow2
pushing to ssh://user@dummy/narrow2
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
Can push to narrower repo if change affects only paths within remote's
narrow spec
$ cd ../narrow2
$ cat >> .hg/hgrc <<EOF
> [narrow]
> serveellipses=True
> EOF
$ hg co -r 'desc("inside 3")'
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo 4 > inside/f
$ hg ci -m 'inside 4'
$ hg push ssh://user@dummy/narrow
pushing to ssh://user@dummy/narrow
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
Can push to narrow repo if change affects only paths outside remote's
narrow spec
$ echo 3 > inside2/f
$ hg ci -m 'inside2 3'
TODO: this should be successful
$ hg push ssh://user@dummy/narrow
pushing to ssh://user@dummy/narrow
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: transaction abort!
remote: rollback completed
remote: abort: data/inside2/f.i@4a1aa07735e6: unknown parent! (reporevlogstore !)
remote: abort: data/inside2/f/index@4a1aa07735e6: no node! (reposimplestore !)
abort: stream ended unexpectedly (got 0 bytes, expected 4)
[255]
Can pull from wider repo if change affects only paths outside remote's
narrow spec
$ echo 4 > inside2/f
$ hg ci -m 'inside2 4'
$ hg log -G -T '{rev} {node|short} {files}\n'
@ 7 d78a96df731d inside2/f
|
o 6 8c26f5218962 inside2/f
|
o 5 ba3480e2f9de inside/f
|
o 4 4e5edd526618 inside/f
|
o 3 81e7e07b7ab0 outside/f
|
o 2 f3993b8c0c2b inside2/f
|
o 1 8cd66ca966b4 inside/f
|
o 0 c8057d6f53ab inside/f inside2/f outside/f
$ cd ../narrow
$ hg log -G -T '{rev} {node|short} {files}\n'
o 4 ba3480e2f9de inside/f
|
@ 3 4e5edd526618 inside/f
|
o 2 81e7e07b7ab0 outside/f
|
o 1 8cd66ca966b4 inside/f
|
o 0 c8057d6f53ab inside/f inside2/f outside/f
$ hg pull ssh://user@dummy/narrow2
pulling from ssh://user@dummy/narrow2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files
new changesets d78a96df731d
(run 'hg update' to get a working copy)
Check that the resulting history is valid in the full repo
$ cd ../narrow2
$ hg push ssh://user@dummy/master
pushing to ssh://user@dummy/master
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 4 changesets with 4 changes to 2 files
$ cd ../master
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checked 8 changesets with 10 changes to 3 files
Can not push to wider repo if change affects paths in wider repo that are
not also in narrower repo
$ cd ../master
$ hg co -r 'desc("inside2 4")'
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo 5 > inside2/f
$ hg ci -m 'inside2 5'
$ hg log -G -T '{rev} {node|short} {files}\n'
@ 8 5970befb64ba inside2/f
|
o 7 d78a96df731d inside2/f
|
o 6 8c26f5218962 inside2/f
|
o 5 ba3480e2f9de inside/f
|
o 4 4e5edd526618 inside/f
|
o 3 81e7e07b7ab0 outside/f
|
o 2 f3993b8c0c2b inside2/f
|
o 1 8cd66ca966b4 inside/f
|
o 0 c8057d6f53ab inside/f inside2/f outside/f
$ cd ../narrow
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files
new changesets * (glob)
(run 'hg update' to get a working copy)
TODO: this should tell the user that their narrow clone does not have the
necessary content to be able to push to the target
$ hg push ssh://user@dummy/narrow2
pushing to ssh://user@dummy/narrow2
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 0 changes to 0 files