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2006-06-20Add "named object array" conceptLinus Torvalds
We've had this notion of a "object_list" for a long time, which eventually grew a "name" member because some users (notably git-rev-list) wanted to name each object as it is generated. That object_list is great for some things, but it isn't all that wonderful for others, and the "name" member is generally not used by everybody. This patch splits the users of the object_list array up into two: the traditional list users, who want the list-like format, and who don't actually use or want the name. And another class of users that really used the list as an extensible array, and generally wanted to name the objects. The patch is fairly straightforward, but it's also biggish. Most of it really just cleans things up: switching the revision parsing and listing over to the array makes things like the builtin-diff usage much simpler (we now see exactly how many members the array has, and we don't get the objects reversed from the order they were on the command line). One of the main reasons for doing this at all is that the malloc overhead of the simple object list was actually pretty high, and the array is just a lot denser. So this patch brings down memory usage by git-rev-list by just under 3% (on top of all the other memory use optimizations) on the mozilla archive. It does add more lines than it removes, and more importantly, it adds a whole new infrastructure for maintaining lists of objects, but on the other hand, the new dynamic array code is pretty obvious. The change to builtin-diff-tree.c shows a fairly good example of why an array interface is sometimes more natural, and just much simpler for everybody. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-18Remove "refs" field from "struct object"Linus Torvalds
This shrinks "struct object" to the absolutely minimal size possible. It now contains /only/ the object flags and the SHA1 hash name of the object. The "refs" field, which is really needed only for fsck, is maintained in a separate hashed lookup-table, allowing all normal users to totally ignore it. This helps memory usage, although not as much as I hoped: it looks like the allocation overhead of malloc (and the alignment constraints in particular) means that while the structure size shrinks, the actual allocation overhead mostly does not. [ That said: memory usage is actually down, but not as much as it should be: I suspect just one of the object types actually ended up shrinking its effective allocation size. To get to the next level, we probably need specialized allocators that don't pad the allocation more than necessary. ] The separation makes for some code cleanup, though, and makes the ref tracking that fsck wants a clearly separate thing. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-18Move "void *util" from "struct object" into "struct commit"Linus Torvalds
Every single user actually wanted this only for commit objects, and we have no reason to waste space on it for other object types. So just move the structure member from the low-level "struct object" into the "struct commit". This leaves the commit object the same size, and removes one unnecessary pointer from all other object allocations. This shrinks memory usage (still at a fairly hefty half-gig, admittedly) of "git-rev-list --all --objects" on the mozilla repo by another 5% in my tests. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-18Shrink "struct object" a bitLinus Torvalds
This shrinks "struct object" by a small amount, by getting rid of the "struct type *" pointer and replacing it with a 3-bit bitfield instead. In addition, we merge the bitfields and the "flags" field, which incidentally should also remove a useless 4-byte padding from the object when in 64-bit mode. Now, our "struct object" is still too damn large, but it's now less obviously bloated, and of the remaining fields, only the "util" (which is not used by most things) is clearly something that should be eventually discarded. This shrinks the "git-rev-list --all" memory use by about 2.5% on the kernel archive (and, perhaps more importantly, on the larger mozilla archive). That may not sound like much, but I suspect it's more on a 64-bit platform. There are other remaining inefficiencies (the parent lists, for example, probably have horrible malloc overhead), but this was pretty obvious. Most of the patch is just changing the comparison of the "type" pointer from one of the constant string pointers to the appropriate new TYPE_xxx small integer constant. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-02-12Use a hashtable for objects instead of a sorted listJohannes Schindelin
In a simple test, this brings down the CPU time from 47 sec to 22 sec. Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-01-07[PATCH] Compilation: zero-length array declaration.Junio C Hamano
ISO C99 (and GCC 3.x or later) lets you write a flexible array at the end of a structure, like this: struct frotz { int xyzzy; char nitfol[]; /* more */ }; GCC 2.95 and 2.96 let you to do this with "char nitfol[0]"; unfortunately this is not allowed by ISO C90. This declares such construct like this: struct frotz { int xyzzy; char nitfol[FLEX_ARRAY]; /* more */ }; and git-compat-util.h defines FLEX_ARRAY to 0 for gcc 2.95 and empty for others. If you are using a C90 C compiler, you should be able to override this with CFLAGS=-DFLEX_ARRAY=1 from the command line of "make". Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-11-17GIT 0.99.9j aka 1.0rc3v1.0rc3v0.99.9jJunio C Hamano
Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-09-16[PATCH] Avoid building object ref lists when not neededLinus Torvalds
The object parsing code builds a generic "this object references that object" because doing a full connectivity check for fsck requires it. However, nothing else really needs it, and it's quite expensive for git-rev-list that can have tons of objects in flight. So, exactly like the commit buffer save thing, add a global flag to disable it, and use it in git-rev-list. Before: $ /usr/bin/time git-rev-list --objects v2.6.12..HEAD | wc -l 12.28user 0.29system 0:12.57elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+26718minor)pagefaults 0swaps 59124 After this change: $ /usr/bin/time git-rev-list --objects v2.6.12..HEAD | wc -l 10.33user 0.18system 0:10.54elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+18509minor)pagefaults 0swaps 59124 and note how the number of pages touched by git-rev-list for this particular object list has shrunk from 26,718 (104 MB) to 18,509 (72 MB). Calculating the total object difference between two git revisions is still clearly the most expensive git operation (both in memory and CPU time), but it's now less than 40% of what it used to be. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-09-11[PATCH] Add function to append to an object_list.Daniel Barkalow
Signed-off-by: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-08-03[PATCH] Object library enhancementsbarkalow@iabervon.org
Add function to look up an object which is entirely unknown, so that it can be put in a list. Various other functions related to lists of objects. Signed-off-by: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-06-27[PATCH] Remove "delta" object representation.Junio C Hamano
Packed delta files created by git-pack-objects seems to be the way to go, and existing "delta" object handling code has exposed the object representation details to too many places. Remove it while we refactor code to come up with a proper interface in sha1_file.c. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-26Ooh. Make git-rev-list --object associate a name with objects.Linus Torvalds
The name isn't unique, it's just the first name that object is reached through, so it's really nothing more than a hint.
2005-06-22[PATCH] Parse tags for absent objectsDaniel Barkalow
Handle parsing a tag for a non-present object. This adds a function to lookup an object with lookup_* for * in a string, so that it can get the right storage based on the "type" line in the tag. Signed-off-by: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-08[PATCH] Anal retentive 'const unsigned char *sha1'Jason McMullan
Make 'sha1' parameters const where possible Signed-off-by: Jason McMullan <jason.mcmullan@timesys.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-06[PATCH] Modify git-rev-list to linearise the commit history in merge order.jon@blackcubes.dyndns.org
This patch linearises the GIT commit history graph into merge order which is defined by invariants specified in Documentation/git-rev-list.txt. The linearisation produced by this patch is superior in an objective sense to that produced by the existing git-rev-list implementation in that the linearisation produced is guaranteed to have the minimum number of discontinuities, where a discontinuity is defined as an adjacent pair of commits in the output list which are not related in a direct child-parent relationship. With this patch a graph like this: a4 --- | \ \ | b4 | |/ | | a3 | | | | | a2 | | | | c3 | | | | | c2 | b3 | | | /| | b2 | | | c1 | | / | b1 a1 | | | a0 | | / root Sorts like this: = a4 | c3 | c2 | c1 ^ b4 | b3 | b2 | b1 ^ a3 | a2 | a1 | a0 = root Instead of this: = a4 | c3 ^ b4 | a3 ^ c2 ^ b3 ^ a2 ^ b2 ^ c1 ^ a1 ^ b1 ^ a0 = root A test script, t/t6000-rev-list.sh, includes a test which demonstrates that the linearisation produced by --merge-order has less discontinuities than the linearisation produced by git-rev-list without the --merge-order flag specified. To see this, do the following: cd t ./t6000-rev-list.sh cd trash cat actual-default-order cat actual-merge-order The existing behaviour of git-rev-list is preserved, by default. To obtain the modified behaviour, specify --merge-order or --merge-order --show-breaks on the command line. This version of the patch has been tested on the git repository and also on the linux-2.6 repository and has reasonable performance on both - ~50-100% slower than the original algorithm. This version of the patch has incorporated a functional equivalent of the Linus' output limiting algorithm into the merge-order algorithm itself. This operates per the notes associated with Linus' commit 337cb3fb8da45f10fe9a0c3cf571600f55ead2ce. This version has incorporated Linus' feedback regarding proposed changes to rev-list.c. (see: [PATCH] Factor out filtering in rev-list.c) This version has improved the way sort_first_epoch marks commits as uninteresting. For more details about this change, refer to Documentation/git-rev-list.txt and http://blackcubes.dyndns.org/epoch/. Signed-off-by: Jon Seymour <jon.seymour@gmail.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-20[PATCH] delta checkNicolas Pitre
This adds knowledge of delta objects to fsck-cache and various object parsing code. A new switch to git-fsck-cache is provided to display the maximum delta depth found in a repository. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-10Mark the variable declarations in .h files as externPetr Baudis
This allows git to be built even with linkers which are not smart enough to join those symbols, and makes this correct C. Pointed out by several people.
2005-04-28[PATCH] Add function to parse an object of unspecified type (take 2)Daniel Barkalow
This adds a function that parses an object from the database when we have to look up its actual type. It also checks the hash of the file, due to its heritage as part of fsck-cache. Signed-Off-By: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-18[PATCH] Header files for object parsingDaniel Barkalow
This adds the structs and function declarations for parsing git objects. Signed-Off-By: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>