Mercurial > hg
view tests/test-merge-commit.t @ 30764:e75463e3179f
protocol: send application/mercurial-0.2 responses to capable clients
With this commit, the HTTP transport now parses the X-HgProto-<N>
header to determine what media type and compression engine to use for
responses. So far, we only compress responses that are already being
compressed with zlib today (stream response types to specific
commands). We can expand things to cover additional response types
later.
The practical side-effect of this commit is that non-zlib compression
engines will be used if both ends support them. This means if both
ends have zstd support, zstd - not zlib - will be used to compress
data!
When cloning the mozilla-unified repository between a local HTTP
server and client, the benefits of non-zlib compression are quite
noticeable:
engine server CPU (s) client CPU (s) bundle size
zlib (l=6) 174.1 283.2 1,148,547,026
zstd (l=1) 99.2 267.3 1,127,513,841
zstd (l=3) 103.1 266.9 1,018,861,363
zstd (l=7) 128.3 269.7 919,190,278
zstd (l=10) 162.0 - 894,547,179
none 95.3 277.2 4,097,566,064
The default zstd compression level is 3. So if you deploy zstd
capable Mercurial to your clients and servers and CPU time on
your server is dominated by "getbundle" requests (clients cloning
and pulling) - and my experience at Mozilla tells me this is often
the case - this commit could drastically reduce your server-side
CPU usage *and* save on bandwidth costs!
Another benefit of this change is that server operators can install
*any* compression engine. While it isn't enabled by default, the
"none" compression engine can now be used to disable wire protocol
compression completely. Previously, commands like "getbundle" always
zlib compressed output, adding considerable overhead to generating
responses. If you are on a high speed network and your server is under
high load, it might be advantageous to trade bandwidth for CPU.
Although, zstd at level 1 doesn't use that much CPU, so I'm not
convinced that disabling compression wholesale is worthwhile. And, my
data seems to indicate a slow down on the client without compression.
I suspect this is due to a lack of buffering resulting in an increase
in socket read() calls and/or the fact we're transferring an extra 3 GB
of data (parsing HTTP chunked transfer and processing extra TCP packets
can add up). This is definitely worth investigating and optimizing. But
since the "none" compressor isn't enabled by default, I'm inclined to
punt on this issue.
This commit introduces tons of tests. Some of these should arguably
have been implemented on previous commits. But it was difficult to
test without the server functionality in place.
| author | Gregory Szorc <gregory.szorc@gmail.com> |
|---|---|
| date | Sat, 24 Dec 2016 15:29:32 -0700 |
| parents | 564a354f7f35 |
| children | eb586ed5d8ce |
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Check that renames are correctly saved by a commit after a merge Test with the merge on 3 having the rename on the local parent $ hg init a $ cd a $ echo line1 > foo $ hg add foo $ hg ci -m '0: add foo' $ echo line2 >> foo $ hg ci -m '1: change foo' $ hg up -C 0 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg mv foo bar $ rm bar $ echo line0 > bar $ echo line1 >> bar $ hg ci -m '2: mv foo bar; change bar' created new head $ hg merge 1 merging bar and foo to bar 0 files updated, 1 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ cat bar line0 line1 line2 $ hg ci -m '3: merge with local rename' $ hg debugindex bar rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 77 ..... 2 d35118874825 000000000000 000000000000 (re) 1 77 76 ..... 3 5345f5ab8abd 000000000000 d35118874825 (re) $ hg debugrename bar bar renamed from foo:9e25c27b87571a1edee5ae4dddee5687746cc8e2 $ hg debugindex foo rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 7 ..... 0 690b295714ae 000000000000 000000000000 (re) 1 7 13 ..... 1 9e25c27b8757 690b295714ae 000000000000 (re) Revert the content change from rev 2: $ hg up -C 2 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ rm bar $ echo line1 > bar $ hg ci -m '4: revert content change from rev 2' created new head $ hg log --template '{rev}:{node|short} {parents}\n' 4:2263c1be0967 2:0f2ff26688b9 3:0555950ead28 2:0f2ff26688b9 1:5cd961e4045d 2:0f2ff26688b9 0:2665aaee66e9 1:5cd961e4045d 0:2665aaee66e9 This should use bar@rev2 as the ancestor: $ hg --debug merge 3 searching for copies back to rev 1 resolving manifests branchmerge: True, force: False, partial: False ancestor: 0f2ff26688b9, local: 2263c1be0967+, remote: 0555950ead28 preserving bar for resolve of bar starting 4 threads for background file closing (?) bar: versions differ -> m (premerge) picked tool ':merge' for bar (binary False symlink False changedelete False) merging bar my bar@2263c1be0967+ other bar@0555950ead28 ancestor bar@0f2ff26688b9 premerge successful 0 files updated, 1 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ cat bar line1 line2 $ hg ci -m '5: merge' $ hg debugindex bar rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 77 ..... 2 d35118874825 000000000000 000000000000 (re) 1 77 76 ..... 3 5345f5ab8abd 000000000000 d35118874825 (re) 2 153 7 ..... 4 ff4b45017382 d35118874825 000000000000 (re) 3 160 13 ..... 5 3701b4893544 ff4b45017382 5345f5ab8abd (re) Same thing, but with the merge on 3 having the rename on the remote parent: $ cd .. $ hg clone -U -r 1 -r 2 a b adding changesets adding manifests adding file changes added 3 changesets with 3 changes to 2 files (+1 heads) $ cd b $ hg up -C 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg merge 2 merging foo and bar to bar 0 files updated, 1 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ cat bar line0 line1 line2 $ hg ci -m '3: merge with remote rename' $ hg debugindex bar rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 77 ..... 2 d35118874825 000000000000 000000000000 (re) 1 77 76 ..... 3 5345f5ab8abd 000000000000 d35118874825 (re) $ hg debugrename bar bar renamed from foo:9e25c27b87571a1edee5ae4dddee5687746cc8e2 $ hg debugindex foo rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 7 ..... 0 690b295714ae 000000000000 000000000000 (re) 1 7 13 ..... 1 9e25c27b8757 690b295714ae 000000000000 (re) Revert the content change from rev 2: $ hg up -C 2 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ rm bar $ echo line1 > bar $ hg ci -m '4: revert content change from rev 2' created new head $ hg log --template '{rev}:{node|short} {parents}\n' 4:2263c1be0967 2:0f2ff26688b9 3:3ffa6b9e35f0 1:5cd961e4045d 2:0f2ff26688b9 2:0f2ff26688b9 0:2665aaee66e9 1:5cd961e4045d 0:2665aaee66e9 This should use bar@rev2 as the ancestor: $ hg --debug merge 3 searching for copies back to rev 1 resolving manifests branchmerge: True, force: False, partial: False ancestor: 0f2ff26688b9, local: 2263c1be0967+, remote: 3ffa6b9e35f0 preserving bar for resolve of bar starting 4 threads for background file closing (?) bar: versions differ -> m (premerge) picked tool ':merge' for bar (binary False symlink False changedelete False) merging bar my bar@2263c1be0967+ other bar@3ffa6b9e35f0 ancestor bar@0f2ff26688b9 premerge successful 0 files updated, 1 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ cat bar line1 line2 $ hg ci -m '5: merge' $ hg debugindex bar rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 77 ..... 2 d35118874825 000000000000 000000000000 (re) 1 77 76 ..... 3 5345f5ab8abd 000000000000 d35118874825 (re) 2 153 7 ..... 4 ff4b45017382 d35118874825 000000000000 (re) 3 160 13 ..... 5 3701b4893544 ff4b45017382 5345f5ab8abd (re) $ cd ..