kernel/git - git - PowerEL Git System

Commit Graph

Author	SHA1	Message	Date
Junio C Hamano	b65982b608	Optimize "diff-index --cached" using cache-tree When running "diff-index --cached" after making a change to only a small portion of the index, there is no point unpacking unchanged subtrees into the index recursively, only to find that all entries match anyway. Tweak unpack_trees() logic that is used to read in the tree object to catch the case where the tree entry we are looking at matches the index as a whole by looking at the cache-tree. As an exercise, after modifying a few paths in the kernel tree, here are a few numbers on my Athlon 64X2 3800+: (without patch, hot cache) $ /usr/bin/time git diff --cached --raw :100644 100644 b57e1f5... e69de29... M Makefile :100644 000000 8c86b72... 0000000... D arch/x86/Makefile :000000 100644 0000000... e69de29... A arche 0.07user 0.02system 0:00.09elapsed 102%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+9407minor)pagefaults 0swaps (with patch, hot cache) $ /usr/bin/time ../git.git/git-diff --cached --raw :100644 100644 b57e1f5... e69de29... M Makefile :100644 000000 8c86b72... 0000000... D arch/x86/Makefile :000000 100644 0000000... e69de29... A arche 0.02user 0.00system 0:00.02elapsed 103%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+2446minor)pagefaults 0swaps Cold cache numbers are very impressive, but it does not matter very much in practice: (without patch, cold cache) $ su root sh -c 'echo 3 >/proc/sys/vm/drop_caches' $ /usr/bin/time git diff --cached --raw :100644 100644 b57e1f5... e69de29... M Makefile :100644 000000 8c86b72... 0000000... D arch/x86/Makefile :000000 100644 0000000... e69de29... A arche 0.06user 0.17system 0:10.26elapsed 2%CPU (0avgtext+0avgdata 0maxresident)k 247032inputs+0outputs (1172major+8237minor)pagefaults 0swaps (with patch, cold cache) $ su root sh -c 'echo 3 >/proc/sys/vm/drop_caches' $ /usr/bin/time ../git.git/git-diff --cached --raw :100644 100644 b57e1f5... e69de29... M Makefile :100644 000000 8c86b72... 0000000... D arch/x86/Makefile :000000 100644 0000000... e69de29... A arche 0.02user 0.01system 0:01.01elapsed 3%CPU (0avgtext+0avgdata 0maxresident)k 18440inputs+0outputs (79major+2369minor)pagefaults 0swaps This of course helps "git status" as well. (without patch, hot cache) $ /usr/bin/time ../git.git/git-status >/dev/null 0.17user 0.18system 0:00.35elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+5336outputs (0major+10970minor)pagefaults 0swaps (with patch, hot cache) $ /usr/bin/time ../git.git/git-status >/dev/null 0.10user 0.16system 0:00.27elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+5336outputs (0major+3921minor)pagefaults 0swaps Signed-off-by: Junio C Hamano <gitster@pobox.com>	16 years ago
Junio C Hamano	d11b8d3425	write-tree --ignore-cache-tree This allows you to discard the cache-tree information before writing the tree out of the index (i.e. it always recomputes the tree object names for all the subtrees). This is only useful as a debug option, so I did not bother documenting it. Signed-off-by: Junio C Hamano <gitster@pobox.com>	16 years ago
Junio C Hamano	b9d37a5420	Move prime_cache_tree() to cache-tree.c The interface to build cache-tree belongs there. Signed-off-by: Junio C Hamano <gitster@pobox.com>	16 years ago
Nanako Shiraishi	7ba04d9f37	cache-tree.c: make cache_tree_find() static This function is not used by any other file. Signed-off-by: Nanako Shiraishi <nanako3@lavabit.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	17 years ago
Junio C Hamano	45525bd022	Make error messages from cherry-pick/revert more sensible The original "rewrite in C" did somewhat a sloppy job while stealing code from git-write-tree. The caller pretends as if the write_tree() function would return an error code and being able to issue a sensible error message itself, but write_tree() function just calls die() and never returns an error. Worse yet, the function claims that it was running git-write-tree (which is no longer true after cherry-pick stole it). Tested-by: Björn Steinbrink <B.Steinbrink@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>	17 years ago
Pierre Habouzit	1dffb8fa80	Small cache_tree_write refactor. This function cannot fail, make it void. Also make write_one act on a const char* instead of a char*. Signed-off-by: Pierre Habouzit <madcoder@debian.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>	18 years ago
Junio C Hamano	6bd20358a9	write-tree: --prefix=<path> The "bind" commit can express an aggregation of multiple projects into a single commit. In such an organization, there would be one project, root of whose tree object is at the same level of the root of the aggregated projects, and other projects have their toplevel in separate subdirectories. Let's call that root level project the "primary project", and call other ones just "subprojects". You would first read-tree the primary project, and then graft the subprojects under their appropriate location using read-tree --prefix=<subdir>/ repeatedly. To write out a tree object from such an index for a subproject, write-tree --prefix=<subdir>/ is used. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	2956dd3bd7	cache_tree_update: give an option to update cache-tree only. When the extra "dryrun" parameter is true, cache_tree_update() recomputes the invalid entry but does not actually creates new tree object. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	7927a55d5b	read-tree: teach 1-way merege and plain read to prime cache-tree. This teaches read-tree to fully populate valid cache-tree when reading a tree from scratch, or reading a single tree into an existing index, reusing only the cached stat information (i.e. one-way merge). We have already taught update-index about cache-tree, so "git checkout" followed by updates to a few path followed by a "git commit" would become very efficient. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	bad68ec924	index: make the index file format extensible. ... and move the cache-tree data into it. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	749864627c	Add cache-tree. The cache_tree data structure is to cache tree object names that would result from the current index file. The idea is to have an optional file to record each tree object name that corresponds to a directory path in the cache when we run write_cache(), and read it back when we run read_cache(). During various index manupulations, we selectively invalidate the parts so that the next write-tree can bypass regenerating tree objects for unchanged parts of the directory hierarchy. We could perhaps make the cache-tree data an optional part of the index file, but that would involve the index format updates, so unless we need it for performance reasons, the current plan is to use a separate file, $GIT_DIR/index.aux to store this information and link it with the index file with the checksum that is already used for index file integrity check. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago

11 Commits (a33fb40fe477fa1a9ce882230415f19378959390)