kernel/git - git - PowerEL Git System

Commit Graph

Author	SHA1	Message	Date
Junio C Hamano	ab7cd7bb8c	pack-objects: finishing touches. This introduces --no-reuse-delta option to disable reusing of existing delta, which is a large part of the optimization introduced by this series. This may become necessary if repeated repacking makes delta chain too long. With this, the output of the command becomes identical to that of the older implementation. But the performance suffers greatly. It still allows reusing non-deltified representations; there is no point uncompressing and recompressing the whole text. It also adds a couple more statistics output, while squelching it under -q flag, which the last round forgot to do. $ time old-git-pack-objects --stdout >/dev/null <RL Generating pack... Done counting 184141 objects. Packing 184141 objects.................... real 12m8.530s user 11m1.450s sys 0m57.920s $ time git-pack-objects --stdout >/dev/null <RL Generating pack... Done counting 184141 objects. Packing 184141 objects..................... Total 184141, written 184141 (delta 138297), reused 178833 (delta 134081) real 0m59.549s user 0m56.670s sys 0m2.400s $ time git-pack-objects --stdout --no-reuse-delta >/dev/null <RL Generating pack... Done counting 184141 objects. Packing 184141 objects..................... Total 184141, written 184141 (delta 134833), reused 47904 (delta 0) real 11m13.830s user 9m45.240s sys 0m44.330s There is one remaining issue when --no-reuse-delta option is not used. It can create delta chains that are deeper than specified. A<--B<--C<--D E F G Suppose we have a delta chain A to D (A is stored in full either in a pack or as a loose object. B is depth1 delta relative to A, C is depth2 delta relative to B...) with loose objects E, F, G. And we are going to pack all of them. B, C and D are left as delta against A, B and C respectively. So A, E, F, and G are examined for deltification, and let's say we decided to keep E expanded, and store the rest as deltas like this: E<--F<--G<--A Oops. We ended up making D a bit too deep, didn't we? B, C and D form a chain on top of A! This is because we did not know what the final depth of A would be, when we checked objects and decided to keep the existing delta. Unfortunately, deferring the decision until just before the deltification is not an option. To be able to make B, C, and D candidates for deltification with the rest, we need to know the type and final unexpanded size of them, but the major part of the optimization comes from the fact that we do not read the delta data to do so -- getting the final size is quite an expensive operation. To prevent this from happening, we should keep A from being deltified. But how would we tell that, cheaply? To do this most precisely, after check_object() runs, each object that is used as the base object of some existing delta needs to be marked with the maximum depth of the objects we decided to keep deltified (in this case, D is depth 3 relative to A, so if no other delta chain that is longer than 3 based on A exists, mark A with 3). Then when attempting to deltify A, we would take that number into account to see if the final delta chain that leads to D becomes too deep. However, this is a bit cumbersome to compute, so we would cheat and reduce the maximum depth for A arbitrarily to depth/4 in this implementation. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	ca5381d43e	pack-objects: finishing touches. This introduces --no-reuse-delta option to disable reusing of existing delta, which is a large part of the optimization introduced by this series. This may become necessary if repeated repacking makes delta chain too long. With this, the output of the command becomes identical to that of the older implementation. But the performance suffers greatly. It still allows reusing non-deltified representations; there is no point uncompressing and recompressing the whole text. It also adds a couple more statistics output, while squelching it under -q flag, which the last round forgot to do. $ time old-git-pack-objects --stdout >/dev/null <RL Generating pack... Done counting 184141 objects. Packing 184141 objects.................... real 12m8.530s user 11m1.450s sys 0m57.920s $ time git-pack-objects --stdout >/dev/null <RL Generating pack... Done counting 184141 objects. Packing 184141 objects..................... Total 184141, written 184141 (delta 138297), reused 178833 (delta 134081) real 0m59.549s user 0m56.670s sys 0m2.400s $ time git-pack-objects --stdout --no-reuse-delta >/dev/null <RL Generating pack... Done counting 184141 objects. Packing 184141 objects..................... Total 184141, written 184141 (delta 134833), reused 47904 (delta 0) real 11m13.830s user 9m45.240s sys 0m44.330s There is one remaining issue when --no-reuse-delta option is not used. It can create delta chains that are deeper than specified. A<--B<--C<--D E F G Suppose we have a delta chain A to D (A is stored in full either in a pack or as a loose object. B is depth1 delta relative to A, C is depth2 delta relative to B...) with loose objects E, F, G. And we are going to pack all of them. B, C and D are left as delta against A, B and C respectively. So A, E, F, and G are examined for deltification, and let's say we decided to keep E expanded, and store the rest as deltas like this: E<--F<--G<--A Oops. We ended up making D a bit too deep, didn't we? B, C and D form a chain on top of A! This is because we did not know what the final depth of A would be, when we checked objects and decided to keep the existing delta. Unfortunately, deferring the decision until just before the deltification is not an option. To be able to make B, C, and D candidates for deltification with the rest, we need to know the type and final unexpanded size of them, but the major part of the optimization comes from the fact that we do not read the delta data to do so -- getting the final size is quite an expensive operation. To prevent this from happening, we should keep A from being deltified. But how would we tell that, cheaply? To do this most precisely, after check_object() runs, each object that is used as the base object of some existing delta needs to be marked with the maximum depth of the objects we decided to keep deltified (in this case, D is depth 3 relative to A, so if no other delta chain that is longer than 3 based on A exists, mark A with 3). Then when attempting to deltify A, we would take that number into account to see if the final delta chain that leads to D becomes too deep. However, this is a bit cumbersome to compute, so we would cheat and reduce the maximum depth for A arbitrarily to depth/4 in this implementation. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	89438677ab	Documentation: spell. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Nikolai Weibull	63ae26f87a	Document the --non-empty command-line option to git-pack-objects. This provides (minimal) documentation for the --non-empty command-line option to the pack-objects command. Signed-off-by: Nikolai Weibull <nikolai@bitwi.se> Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	12ea5bea58	Update git-pack-objects documentation. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Christian Meder	72e9340cfd	Convert usage of GIT and Git into git Convert usage of GIT and Git into git. Signed-off-by: Christian Meder <chris@absolutegiganten.org> Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	98438bd0e8	Remove the version tags from the manpages Signed-off-by: Christian Meder <chris@absolutegiganten.org> Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Jonas Fonseca	df8baa42fe	[PATCH] Random documentation fixes The fixes focuses on improving the HTML output. Most noteworthy: - Fix the Makefile to also make various *.html files depend on included files. - Consistently use 'NOTE: ...' instead of '[ ... ]' for additional info. - Fix ending '::' for description lists in OPTION section etc. - Fix paragraphs in description lists ending up as preformated text. - Always use listingblocks (preformatted text wrapped in lines with -----) for examples that span empty lines, so they are put in only one HTML block. - Use '1.' instead of '(1)' for numbered lists. - Fix linking to other GIT docs. - git-rev-list.txt: put option descriptions in an OPTION section. Signed-off-by: Jonas Fonseca <fonseca@diku.dk> Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Sergey Vlasov	a7154e916c	[PATCH] Documentation: Update all files to use the new gitlink: macro The replacement was performed automatically by these commands: perl -pi -e 's/link:(git.+)\.html\[\1\]/gitlink:$1\[1\]/g' \ README Documentation/.txt perl -pi -e 's/link:git\.html\[git\]/gitlink:git\[7\]/g' \ README Documentation/.txt Signed-off-by: Sergey Vlasov <vsu@altlinux.ru> Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	215a7ad1ef	Big tool rename. As promised, this is the "big tool rename" patch. The primary differences since 0.99.6 are: (1) git-*-script are no more. The commands installed do not have any such suffix so users do not have to remember if something is implemented as a shell script or not. (2) Many command names with 'cache' in them are renamed with 'index' if that is what they mean. There are backward compatibility symblic links so that you and Porcelains can keep using the old names, but the backward compatibility support is expected to be removed in the near future. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	e31bb3bb93	[PATCH] Add documentation for git repack and git-prune-packed. [jc: the patch forgot to update the main git.txt documentation, making all these new documentation practically no-op, so I added a minimum attempt linking them from there.] Signed-off-by: Ryan Anderson <ryan@michonline.com>	20 years ago
Johannes Schindelin	2c6e477195	[PATCH] Assorted documentation patches [jc: Johannes spent time and effort to see how consistent our use of terminilogy is, and as a byproduct made these corrections not related to the terminology unification. I really appreciate it.] Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>	20 years ago
Junio C Hamano	5f40520f8c	[PATCH] Documentation: packed GIT support commands. This adds documentation for creating packed archives, inspecting, validating them, and unpacking them. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>	20 years ago

12 Commits (0c1fc940eeae051e890304c40d1e66a478afadc8)