view tests/test-commit-multiple.t @ 39583:ee087f0d7db5

util: allow lrucachedict to track cost of entries

Currently, lrucachedict allows tracking of arbitrary items with the
only limit being the total number of items in the cache.

Caches can be a lot more useful when they are bound by the size
of the items in them rather than the number of elements in the
cache.

In preparation for teaching lrucachedict to enforce a max size of
cached items, we teach lrucachedict to optionally associate a numeric
cost value with each node.

We purposefully let the caller define their own cost for nodes.

This does introduce some overhead. Most of it comes from __setitem__,
since that function now calls into insert(), thus introducing Python
function call overhead.

$ hg perflrucachedict --size 4 --gets 1000000 --sets 1000000 --mixed 1000000
! gets
! wall 0.599552 comb 0.600000 user 0.600000 sys 0.000000 (best of 17)
! wall 0.614643 comb 0.610000 user 0.610000 sys 0.000000 (best of 17)
! inserts
! <not available>
! wall 0.655817 comb 0.650000 user 0.650000 sys 0.000000 (best of 16)
! sets
! wall 0.540448 comb 0.540000 user 0.540000 sys 0.000000 (best of 18)
! wall 0.805644 comb 0.810000 user 0.810000 sys 0.000000 (best of 13)
! mixed
! wall 0.651556 comb 0.660000 user 0.660000 sys 0.000000 (best of 15)
! wall 0.781357 comb 0.780000 user 0.780000 sys 0.000000 (best of 13)

$ hg perflrucachedict --size 1000 --gets 1000000 --sets 1000000 --mixed 1000000
! gets
! wall 0.621014 comb 0.620000 user 0.620000 sys 0.000000 (best of 16)
! wall 0.615146 comb 0.620000 user 0.620000 sys 0.000000 (best of 17)
! inserts
! <not available>
! wall 0.698115 comb 0.700000 user 0.700000 sys 0.000000 (best of 15)
! sets
! wall 0.560247 comb 0.560000 user 0.560000 sys 0.000000 (best of 18)
! wall 0.832495 comb 0.830000 user 0.830000 sys 0.000000 (best of 12)
! mixed
! wall 0.686172 comb 0.680000 user 0.680000 sys 0.000000 (best of 15)
! wall 0.841359 comb 0.840000 user 0.840000 sys 0.000000 (best of 12)

We're still under 1us per insert, which seems like reasonable
performance for a cache.

If we comment out updating of self.totalcost during insert(),
performance of insert() is identical to __setitem__ before. However,
I don't want to make total cost evaluation lazy because it has
significant performance implications for when we need to evaluate the
total cost at mutation time (it requires a cache traversal, which could
be expensive for large caches).

Differential Revision: https://phab.mercurial-scm.org/D4502

# reproduce issue2264, issue2516

create test repo
  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > transplant =
  > EOF
  $ hg init repo
  $ cd repo
  $ template="{rev}  {desc|firstline}  [{branch}]\n"

# we need to start out with two changesets on the default branch
# in order to avoid the cute little optimization where transplant
# pulls rather than transplants
add initial changesets
  $ echo feature1 > file1
  $ hg ci -Am"feature 1"
  adding file1
  $ echo feature2 >> file2
  $ hg ci -Am"feature 2"
  adding file2

# The changes to 'bugfix' are enough to show the bug: in fact, with only
# those changes, it's a very noisy crash ("RuntimeError: nothing
# committed after transplant").  But if we modify a second file in the
# transplanted changesets, the bug is much more subtle: transplant
# silently drops the second change to 'bugfix' on the floor, and we only
# see it when we run 'hg status' after transplanting.  Subtle data loss
# bugs are worse than crashes, so reproduce the subtle case here.
commit bug fixes on bug fix branch
  $ hg branch fixes
  marked working directory as branch fixes
  (branches are permanent and global, did you want a bookmark?)
  $ echo fix1 > bugfix
  $ echo fix1 >> file1
  $ hg ci -Am"fix 1"
  adding bugfix
  $ echo fix2 > bugfix
  $ echo fix2 >> file1
  $ hg ci -Am"fix 2"
  $ hg log -G --template="$template"
  @  3  fix 2  [fixes]
  |
  o  2  fix 1  [fixes]
  |
  o  1  feature 2  [default]
  |
  o  0  feature 1  [default]
  
transplant bug fixes onto release branch
  $ hg update 0
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg branch release
  marked working directory as branch release
  $ hg transplant 2 3
  applying [0-9a-f]{12} (re)
  [0-9a-f]{12} transplanted to [0-9a-f]{12} (re)
  applying [0-9a-f]{12} (re)
  [0-9a-f]{12} transplanted to [0-9a-f]{12} (re)
  $ hg log -G --template="$template"
  @  5  fix 2  [release]
  |
  o  4  fix 1  [release]
  |
  | o  3  fix 2  [fixes]
  | |
  | o  2  fix 1  [fixes]
  | |
  | o  1  feature 2  [default]
  |/
  o  0  feature 1  [default]
  
  $ hg status
  $ hg status --rev 0:4
  M file1
  A bugfix
  $ hg status --rev 4:5
  M bugfix
  M file1

now test that we fixed the bug for all scripts/extensions
  $ cat > $TESTTMP/committwice.py <<__EOF__
  > from mercurial import ui, hg, match, node
  > from time import sleep
  > 
  > def replacebyte(fn, b):
  >     f = open(fn, "rb+")
  >     f.seek(0, 0)
  >     f.write(b)
  >     f.close()
  > 
  > def printfiles(repo, rev):
  >     repo.ui.status(b"revision %d files: [%s]\n"
  >                    % (rev, b', '.join(b"'%s'" % f
  >                                       for f in repo[rev].files())))
  > 
  > repo = hg.repository(ui.ui.load(), b'.')
  > assert len(repo) == 6, \
  >        "initial: len(repo): %d, expected: 6" % len(repo)
  > 
  > replacebyte(b"bugfix", b"u")
  > sleep(2)
  > try:
  >     repo.ui.status(b"PRE: len(repo): %d\n" % len(repo))
  >     wlock = repo.wlock()
  >     lock = repo.lock()
  >     replacebyte(b"file1", b"x")
  >     repo.commit(text=b"x", user=b"test", date=(0, 0))
  >     replacebyte(b"file1", b"y")
  >     repo.commit(text=b"y", user=b"test", date=(0, 0))
  >     repo.ui.status(b"POST: len(repo): %d\n" % len(repo))
  > finally:
  >     lock.release()
  >     wlock.release()
  > printfiles(repo, 6)
  > printfiles(repo, 7)
  > __EOF__
  $ $PYTHON $TESTTMP/committwice.py
  PRE: len(repo): 6
  POST: len(repo): 8
  revision 6 files: ['bugfix', 'file1']
  revision 7 files: ['file1']

Do a size-preserving modification outside of that process
  $ echo abcd > bugfix
  $ hg status
  M bugfix
  $ hg log --template "{rev}  {desc}  {files}\n" -r5:
  5  fix 2  bugfix file1
  6  x  bugfix file1
  7  y  file1

  $ cd ..