view tests/test-static-http.t @ 35793:4fb2bb61597c

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

#require killdaemons

  $ hg clone http://localhost:$HGPORT/ copy
  abort: * (glob)
  [255]
  $ test -d copy
  [1]

This server doesn't do range requests so it's basically only good for
one pull

  $ $PYTHON "$TESTDIR/dumbhttp.py" -p $HGPORT --pid dumb.pid \
  > --logfile server.log
  $ cat dumb.pid >> $DAEMON_PIDS
  $ hg init remote
  $ cd remote
  $ echo foo > bar
  $ echo c2 > '.dotfile with spaces'
  $ hg add
  adding .dotfile with spaces
  adding bar
  $ hg commit -m"test"
  $ hg tip
  changeset:   0:02770d679fb8
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     test
  
  $ cd ..
  $ hg clone static-http://localhost:$HGPORT/remote local
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  new changesets 02770d679fb8
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd local
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 1 changesets, 2 total revisions
  $ cat bar
  foo
  $ cd ../remote
  $ echo baz > quux
  $ hg commit -A -mtest2
  adding quux

check for HTTP opener failures when cachefile does not exist

  $ rm .hg/cache/*
  $ cd ../local
  $ cat >> .hg/hgrc <<EOF
  > [hooks]
  > changegroup = sh -c "printenv.py changegroup"
  > EOF
  $ hg pull
  pulling from static-http://localhost:$HGPORT/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets 4ac2e3648604
  changegroup hook: HG_HOOKNAME=changegroup HG_HOOKTYPE=changegroup HG_NODE=4ac2e3648604439c580c69b09ec9d93a88d93432 HG_NODE_LAST=4ac2e3648604439c580c69b09ec9d93a88d93432 HG_SOURCE=pull HG_TXNID=TXN:$ID$ HG_URL=http://localhost:$HGPORT/remote
  (run 'hg update' to get a working copy)

trying to push

  $ hg update
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo more foo >> bar
  $ hg commit -m"test"
  $ hg push
  pushing to static-http://localhost:$HGPORT/remote
  abort: destination does not support push
  [255]

trying clone -r

  $ cd ..
  $ hg clone -r doesnotexist static-http://localhost:$HGPORT/remote local0
  abort: unknown revision 'doesnotexist'!
  [255]
  $ hg clone -r 0 static-http://localhost:$HGPORT/remote local0
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  new changesets 02770d679fb8
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

test with "/" URI (issue747) and subrepo

  $ hg init
  $ hg init sub
  $ touch sub/test
  $ hg -R sub commit -A -m "test"
  adding test
  $ hg -R sub tag not-empty
  $ echo sub=sub > .hgsub
  $ echo a > a
  $ hg add a .hgsub
  $ hg -q ci -ma
  $ hg clone static-http://localhost:$HGPORT/ local2
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 3 changes to 3 files
  new changesets a9ebfbe8e587
  updating to branch default
  cloning subrepo sub from static-http://localhost:$HGPORT/sub
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  new changesets be090ea66256:322ea90975df
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd local2
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  3 files, 1 changesets, 3 total revisions
  checking subrepo links
  $ cat a
  a
  $ hg paths
  default = static-http://localhost:$HGPORT/

test with empty repo (issue965)

  $ cd ..
  $ hg init remotempty
  $ hg clone static-http://localhost:$HGPORT/remotempty local3
  no changes found
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd local3
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  0 files, 0 changesets, 0 total revisions
  $ hg paths
  default = static-http://localhost:$HGPORT/remotempty

test with non-repo

  $ cd ..
  $ mkdir notarepo
  $ hg clone static-http://localhost:$HGPORT/notarepo local3
  abort: 'http://localhost:$HGPORT/notarepo' does not appear to be an hg repository!
  [255]

Clone with tags and branches works

  $ hg init remote-with-names
  $ cd remote-with-names
  $ echo 0 > foo
  $ hg -q commit -A -m initial
  $ echo 1 > foo
  $ hg commit -m 'commit 1'
  $ hg -q up 0
  $ hg branch mybranch
  marked working directory as branch mybranch
  (branches are permanent and global, did you want a bookmark?)
  $ echo 2 > foo
  $ hg commit -m 'commit 2 (mybranch)'
  $ hg tag -r 1 'default-tag'
  $ hg tag -r 2 'branch-tag'

  $ cd ..

  $ hg clone static-http://localhost:$HGPORT/remote-with-names local-with-names
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 2 files (+1 heads)
  new changesets 68986213bd44:0c325bd2b5a7
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Clone a specific branch works

  $ hg clone -r mybranch static-http://localhost:$HGPORT/remote-with-names local-with-names-branch
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 2 files
  new changesets 68986213bd44:0c325bd2b5a7
  updating to branch mybranch
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

Clone a specific tag works

  $ hg clone -r default-tag static-http://localhost:$HGPORT/remote-with-names local-with-names-tag
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets 68986213bd44:4ee3fcef1c80
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ killdaemons.py

List of files accessed over HTTP:

  $ cat server.log | sed -n -e 's|.*GET \(/[^ ]*\).*|\1|p' | sort -u
  /.hg/bookmarks
  /.hg/bookmarks.current
  /.hg/cache/hgtagsfnodes1
  /.hg/requires
  /.hg/store/00changelog.i
  /.hg/store/00manifest.i
  /.hg/store/data/%7E2ehgsub.i
  /.hg/store/data/%7E2ehgsubstate.i
  /.hg/store/data/a.i
  /notarepo/.hg/00changelog.i
  /notarepo/.hg/requires
  /remote-with-names/.hg/bookmarks
  /remote-with-names/.hg/bookmarks.current
  /remote-with-names/.hg/cache/branch2-served
  /remote-with-names/.hg/cache/hgtagsfnodes1
  /remote-with-names/.hg/cache/tags2-served
  /remote-with-names/.hg/localtags
  /remote-with-names/.hg/requires
  /remote-with-names/.hg/store/00changelog.i
  /remote-with-names/.hg/store/00manifest.i
  /remote-with-names/.hg/store/data/%7E2ehgtags.i
  /remote-with-names/.hg/store/data/foo.i
  /remote/.hg/bookmarks
  /remote/.hg/bookmarks.current
  /remote/.hg/cache/branch2-base
  /remote/.hg/cache/branch2-immutable
  /remote/.hg/cache/branch2-served
  /remote/.hg/cache/hgtagsfnodes1
  /remote/.hg/cache/rbc-names-v1
  /remote/.hg/cache/tags2-served
  /remote/.hg/localtags
  /remote/.hg/requires
  /remote/.hg/store/00changelog.i
  /remote/.hg/store/00manifest.i
  /remote/.hg/store/data/%7E2edotfile%20with%20spaces.i
  /remote/.hg/store/data/%7E2ehgtags.i
  /remote/.hg/store/data/bar.i
  /remote/.hg/store/data/quux.i
  /remotempty/.hg/bookmarks
  /remotempty/.hg/bookmarks.current
  /remotempty/.hg/requires
  /remotempty/.hg/store/00changelog.i
  /remotempty/.hg/store/00manifest.i
  /sub/.hg/bookmarks
  /sub/.hg/bookmarks.current
  /sub/.hg/cache/hgtagsfnodes1
  /sub/.hg/requires
  /sub/.hg/store/00changelog.i
  /sub/.hg/store/00manifest.i
  /sub/.hg/store/data/%7E2ehgtags.i
  /sub/.hg/store/data/test.i