kernel/git - git - PowerEL Git System

Tree: e1f68c66d5

Author	SHA1	Message	Date
Kevin Willford	b3dfeebb92	rebase: avoid computing unnecessary patch IDs The `rebase` family of Git commands avoid applying patches that were already integrated upstream. They do that by using the revision walking option that computes the patch IDs of the two sides of the rebase (local-only patches vs upstream-only ones) and skipping those local patches whose patch ID matches one of the upstream ones. In many cases, this causes unnecessary churn, as already the set of paths touched by a given commit would suffice to determine that an upstream patch has no local equivalent. This hurts performance in particular when there are a lot of upstream patches, and/or large ones. Therefore, let's introduce the concept of a "diff-header-only" patch ID, compare those first, and only evaluate the "full" patch ID lazily. Please note that in contrast to the "full" patch IDs, those "diff-header-only" patch IDs are prone to collide with one another, as adjacent commits frequently touch the very same files. Hence we now have to be careful to allow multiple hash entries with the same hash. We accomplish that by using the hashmap_add() function that does not even test for hash collisions. This also allows us to evaluate the full patch ID lazily, i.e. only when we found commits with matching diff-header-only patch IDs. We add a performance test that demonstrates ~1-6% improvement. In practice this will depend on various factors such as how many upstream changes and how big those changes are along with whether file system caches are cold or warm. As Git's test suite has no way of catching performance regressions, we also add a regression test that verifies that the full patch ID computation is skipped when the diff-header-only computation suffices. Signed-off-by: Kevin Willford <kcwillford@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	9 years ago
Kevin Willford	683f17ec44	patch-ids: replace the seen indicator with a commit pointer The cherry_pick_list was looping through the original side checking the seen indicator and setting the cherry_flag on the commit. If we save off the commit in the patch_id we can set the cherry_flag on the correct commit when running through the other side when a patch_id match is found. Signed-off-by: Kevin Willford <kcwillford@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	9 years ago
Kevin Willford	dfb7a1b4d0	patch-ids: stop using a hand-rolled hashmap implementation This change will use the hashmap from the hashmap.h to keep track of the patch_ids that have been encountered instead of using an internal implementation. This simplifies the implementation of the patch ids. Signed-off-by: Kevin Willford <kcwillford@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	9 years ago
Xiaolong Ye	ded2c097ba	patch-ids: make commit_patch_id() a public helper function Make commit_patch_id() available to other builtins. Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	9 years ago
Junio C Hamano	5d23e133d2	Refactor patch-id filtering out of git-cherry and git-format-patch. This implements the patch-id computation and recording library, patch-ids.c, and rewrites the get_patch_ids() function used in cherry and format-patch to use it, so that they do not pollute the object namespace. Earlier code threw non-objects into the in-core object database, and hoped for not getting bitten by SHA-1 collisions. While it may be practically Ok, it still was an ugly hack. Signed-off-by: Junio C Hamano <junkio@cox.net>	18 years ago