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Revision f43ba60e2c3bec4925eee229fa0f420dd1296f0c authored by Linus Torvalds on 13 April 2006, 17:01:02 UTC, committed by Junio C Hamano on 13 April 2006, 18:26:56 UTC 
Use less memory in "git log"
 
This trivially avoids keeping the commit message data around after we
don't need it any more, avoiding a continually growing "git log" memory
footprint.

It's not a huge deal, but it's somewhat noticeable. For the current kernel
tree, doing a full "git log" I got

 - before: /usr/bin/time git log > /dev/null
	0.81user 0.02system 0:00.84elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k
	0inputs+0outputs (0major+8851minor)pagefaults 0swaps

 - after: /usr/bin/time git log > /dev/null
	0.79user 0.03system 0:00.83elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k
	0inputs+0outputs (0major+5039minor)pagefaults 0swaps

ie the touched pages dropped from 8851 to 5039. For the historic kernel
archive, the numbers are 18357->11037 minor page faults.

We could/should in theory free the commits themselves, but that's really a
lot harder, since during revision traversal we may hit the same commit
twice through different children having it as a parent, even after we've
shown it once (when that happens, we'll silently ignore it next time, but
we still need the "struct commit" to know).

And as the commit message data is clearly the biggest part of the commit,
this is the really easy 60% solution.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
1 parent d533524
Raw File
t5000-tar-tree.sh 
#!/bin/sh
#
# Copyright (C) 2005 Rene Scharfe
#

test_description='git-tar-tree and git-get-tar-commit-id test

This test covers the topics of file contents, commit date handling and
commit id embedding:

  The contents of the repository is compared to the extracted tar
  archive.  The repository contains simple text files, symlinks and a
  binary file (/bin/sh).  Only pathes shorter than 99 characters are
  used.

  git-tar-tree applies the commit date to every file in the archive it
  creates.  The test sets the commit date to a specific value and checks
  if the tar archive contains that value.

  When giving git-tar-tree a commit id (in contrast to a tree id) it
  embeds this commit id into the tar archive as a comment.  The test
  checks the ability of git-get-tar-commit-id to figure it out from the
  tar file.

'

. ./test-lib.sh
TAR=${TAR:-tar}

test_expect_success \
    'populate workdir' \
    'mkdir a b c &&
     echo simple textfile >a/a &&
     mkdir a/bin &&
     cp /bin/sh a/bin &&
     ln -s a a/l1 &&
     (p=long_path_to_a_file && cd a &&
      for depth in 1 2 3 4 5; do mkdir $p && cd $p; done &&
      echo text >file_with_long_path) &&
     (cd a && find .) | sort >a.lst'

test_expect_success \
    'add files to repository' \
    'find a -type f | xargs git-update-index --add &&
     find a -type l | xargs git-update-index --add &&
     treeid=`git-write-tree` &&
     echo $treeid >treeid &&
     git-update-ref HEAD $(TZ=GMT GIT_COMMITTER_DATE="2005-05-27 22:00:00" \
     git-commit-tree $treeid </dev/null)'

test_expect_success \
    'git-tar-tree' \
    'git-tar-tree HEAD >b.tar'

test_expect_success \
    'validate file modification time' \
    'TZ=GMT $TAR tvf b.tar a/a |
     awk \{print\ \$4,\ \(length\(\$5\)\<7\)\ ?\ \$5\":00\"\ :\ \$5\} \
     >b.mtime &&
     echo "2005-05-27 22:00:00" >expected.mtime &&
     diff expected.mtime b.mtime'

test_expect_success \
    'git-get-tar-commit-id' \
    'git-get-tar-commit-id <b.tar >b.commitid &&
     diff .git/$(git-symbolic-ref HEAD) b.commitid'

test_expect_success \
    'extract tar archive' \
    '(cd b && $TAR xf -) <b.tar'

test_expect_success \
    'validate filenames' \
    '(cd b/a && find .) | sort >b.lst &&
     diff a.lst b.lst'

test_expect_success \
    'validate file contents' \
    'diff -r a b/a'

test_expect_success \
    'git-tar-tree with prefix' \
    'git-tar-tree HEAD prefix >c.tar'

test_expect_success \
    'extract tar archive with prefix' \
    '(cd c && $TAR xf -) <c.tar'

test_expect_success \
    'validate filenames with prefix' \
    '(cd c/prefix/a && find .) | sort >c.lst &&
     diff a.lst c.lst'

test_expect_success \
    'validate file contents with prefix' \
    'diff -r a c/prefix/a'

test_done
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