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* Merge branch 'jk/repack-pack-writebitmaps-config'Junio C Hamano2014-06-25
|\ | | | | | | | | | | | | | | * jk/repack-pack-writebitmaps-config: t7700: drop explicit --no-pack-kept-objects from .keep test repack: introduce repack.writeBitmaps config option repack: simplify handling of --write-bitmap-index pack-objects: stop respecting pack.writebitmaps
| * pack-objects: stop respecting pack.writebitmapsJeff King2014-06-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The handling of the pack.writebitmaps config option originally happened in pack-objects, which is quite low-level. It would make more sense for drivers of pack-objects to read the config, and then manipulate pack-objects with command-line options. Recently, repack learned to do so, making the low-level read of pack.writebitmaps redundant here. Other callers, like upload-pack, would not generally want to write bitmaps anyway. This could be considered a regression for somebody who is driving pack-objects themselves outside of repack and expects the config option to be used. However, such users seem rather unlikely given how new the bitmap code is (and the fact that they would basically be reimplementing repack in the first place). Note that we do not do anything with pack.writeBitmapHashCache here. That option is not about "do we write bimaps", but rather "when we are writing bitmaps, how do we do it?". You would want that to kick in anytime you decide to write them, similar to how pack.indexVersion is used. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | Merge branch 'jk/pack-bitmap'Junio C Hamano2014-04-08
|\ \ | | | | | | | | | | | | | | | * jk/pack-bitmap: pack-objects: do not reuse packfiles without --delta-base-offset add `ignore_missing_links` mode to revwalk
| * | pack-objects: do not reuse packfiles without --delta-base-offsetJeff King2014-04-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we are sending a packfile to a remote, we currently try to reuse a whole chunk of packfile without bothering to look at the individual objects. This can make things like initial clones much lighter on the server, as we can just dump the packfile bytes. However, it's possible that the other side cannot read our packfile verbatim. For example, we may have objects stored as OFS_DELTA, but the client is an antique version of git that only understands REF_DELTA. We negotiate this capability over the fetch protocol. A normal pack-objects run will convert OFS_DELTA into REF_DELTA on the fly, but the "reuse pack" code path never even looks at the objects. This patch disables packfile reuse if the other side is missing any capabilities that we might have used in the on-disk pack. Right now the only one is OFS_DELTA, but we may need to expand in the future (e.g., if packv4 introduces new object types). We could be more thorough and only disable reuse in this case when we actually have an OFS_DELTA to send, but: 1. We almost always will have one, since we prefer OFS_DELTA to REF_DELTA when possible. So this case would almost never come up. 2. Looking through the objects defeats the purpose of the optimization, which is to do as little work as possible to get the bytes to the remote. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | Merge branch 'jl/nor-or-nand-and'Junio C Hamano2014-04-08
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Eradicate mistaken use of "nor" (that is, essentially "nor" used not in "neither A nor B" ;-)) from in-code comments, command output strings, and documentations. * jl/nor-or-nand-and: code and test: fix misuses of "nor" comments: fix misuses of "nor" contrib: fix misuses of "nor" Documentation: fix misuses of "nor"
| * | | comments: fix misuses of "nor"Justin Lebar2014-03-31
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Justin Lebar <jlebar@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | Merge branch 'jk/pack-bitmap-progress'Junio C Hamano2014-03-28
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The progress output while repacking and transferring objects showed an apparent large silence while writing the objects out of existing packfiles, when the reachability bitmap was in use. * jk/pack-bitmap-progress: pack-objects: show reused packfile objects in "Counting objects" pack-objects: show progress for reused packfiles
| * | | | pack-objects: show reused packfile objects in "Counting objects"Jeff King2014-03-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we are sending a pack for push or fetch, we may reuse a chunk of packfile without even parsing it. The progress meter then looks like this: Reusing existing pack: 3440489, done. Counting objects: 3, done. The first line shows that we are reusing a large chunk of objects, and then we further count any objects not included in the reused portion with an actual traversal. These are all implementation details that the user does not need to care about. Instead, we can show the reused objects in the normal "counting..." progress meter (which will simply go much faster than normal), and then continue to add to it as we traverse. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * | | | pack-objects: show progress for reused packfilesJeff King2014-03-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the "--all-progress" option is in effect, pack-objects shows a progress report for the "writing" phase. If the repository has bitmaps and we are reusing a packfile, the user sees no progress update until the whole packfile is sent. Since this is typically the bulk of what is being written, it can look like git hangs during this phase, even though the transfer is proceeding. This generally only happens with "git push" from a repository with bitmaps. We do not use "--all-progress" for fetch (since the result is going to index-pack on the client, which takes care of progress reporting). And for regular repacks to disk, we do not reuse packfiles. We already have the progress meter setup during write_reused_pack; we just need to call display_progress whiel we are writing out the pack. The progress meter is attached to our output descriptor, so it automatically handles the throughput measurements. However, we need to update the object count as we go, since that is what feeds the percentage we show. We aren't actually parsing the packfile as we send it, so we have no idea how many objects we have sent; we only know that at the end of N bytes, we will have sent M objects. So we cheat a little and assume each object is M/N bytes (i.e., the mean of the objects we are sending). While this isn't strictly true, it actually produces a more pleasing progress meter for the user, as it moves smoothly and predictably (and nobody really cares about the object count; they care about the percentage, and the object count is a proxy for that). One alternative would be to actually show two progress meters: one for the reused pack, and one for the rest of the objects. That would more closely reflect the data we have (the first would be measured in bytes, and the second measured in objects). But it would also be more complex and annoying to the user; rather than seeing one progress meter counting up to 100%, they would finish one meter, then start another one at zero. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | | Merge branch 'jk/pack-bitmap'Junio C Hamano2014-03-28
|\ \ \ \ \ | | |_|/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of dying when asked to (re)pack with the reachability bitmap when a bitmap cannot be built, just (re)pack without producing a bitmap in such a case, with a warning. * jk/pack-bitmap: pack-objects: turn off bitmaps when skipping objects
| * | | | pack-objects: turn off bitmaps when skipping objectsJeff King2014-03-17
| | |_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The pack bitmap format requires that we have a single bit for each object in the pack, and that each object's bitmap represents its complete set of reachable objects. Therefore we have no way to represent the bitmap of an object which references objects outside the pack. We notice this problem while generating the bitmaps, as we try to find the offset of a particular object and realize that we do not have it. In this case we die, and neither the bitmap nor the pack is generated. This is correct, but perhaps a little unfriendly. If you have bitmaps turned on in the config, many repacks will fail which would otherwise succeed. E.g., incremental repacks, repacks with "-l" when you have alternates, ".keep" files. Instead, this patch notices early that we are omitting some objects from the pack and turns off bitmaps (with a warning). Note that this is not strictly correct, as it's possible that the object being omitted is not reachable from any other object in the pack. In practice, this is almost never the case, and there are two advantages to doing it this way: 1. The code is much simpler, as we do not have to cleanly abort the bitmap-generation process midway through. 2. We do not waste time partially generating bitmaps only to find out that some object deep in the history is not being packed. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | Merge branch 'nd/upload-pack-shallow'Junio C Hamano2014-03-21
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Serving objects from a shallow repository needs to write a temporary file to be used, but the serving upload-pack may not have write access to the repository which is meant to be read-only. Instead feed these temporary shallow bounds from the standard input of pack-objects so that we do not have to use a temporary file. * nd/upload-pack-shallow: upload-pack: send shallow info over stdin to pack-objects
| * | | | upload-pack: send shallow info over stdin to pack-objectsNguyễn Thái Ngọc Duy2014-03-11
| | |_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before cdab485 (upload-pack: delegate rev walking in shallow fetch to pack-objects - 2013-08-16) upload-pack does not write to the source repository. cdab485 starts to write $GIT_DIR/shallow_XXXXXX if it's a shallow fetch, so the source repo must be writable. git:// servers do not need write access to repos and usually don't have it, which means cdab485 breaks shallow clone over git:// Instead of using a temporary file as the media for shallow points, we can send them over stdin to pack-objects as well. Prepend shallow SHA-1 with --shallow so pack-objects knows what is what. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | Merge branch 'sh/finish-tmp-packfile'Junio C Hamano2014-03-18
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | * sh/finish-tmp-packfile: finish_tmp_packfile():use strbuf for pathname construction
| * | | | finish_tmp_packfile():use strbuf for pathname constructionSun He2014-03-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The old version fixes a maximum length on the buffer, which could be a problem if one is not certain of the length of get_object_directory(). Using strbuf can avoid the protential bug. Helped-by: Michael Haggerty <mhagger@alum.mit.edu> Helped-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Sun He <sunheehnus@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * | | | Merge branch 'sh/write-pack-file-warning-message-fix' into ↵Junio C Hamano2014-03-03
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sh/finish-tmp-packfile * sh/write-pack-file-warning-message-fix: write_pack_file: use correct variable in diagnostic
* | \ \ \ \ Merge branch 'dd/use-alloc-grow'Junio C Hamano2014-03-18
|\ \ \ \ \ \ | |_|_|_|_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace open-coded reallocation with ALLOC_GROW() macro. * dd/use-alloc-grow: sha1_file.c: use ALLOC_GROW() in pretend_sha1_file() read-cache.c: use ALLOC_GROW() in add_index_entry() builtin/mktree.c: use ALLOC_GROW() in append_to_tree() attr.c: use ALLOC_GROW() in handle_attr_line() dir.c: use ALLOC_GROW() in create_simplify() reflog-walk.c: use ALLOC_GROW() replace_object.c: use ALLOC_GROW() in register_replace_object() patch-ids.c: use ALLOC_GROW() in add_commit() diffcore-rename.c: use ALLOC_GROW() diff.c: use ALLOC_GROW() commit.c: use ALLOC_GROW() in register_commit_graft() cache-tree.c: use ALLOC_GROW() in find_subtree() bundle.c: use ALLOC_GROW() in add_to_ref_list() builtin/pack-objects.c: use ALLOC_GROW() in check_pbase_path()
| * | | | | builtin/pack-objects.c: use ALLOC_GROW() in check_pbase_path()Dmitry S. Dolzhenko2014-03-03
| | |_|/ / | |/| | | | | | | | | | | | | | | | | | Signed-off-by: Dmitry S. Dolzhenko <dmitrys.dolzhenko@yandex.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | | Merge branch 'sh/write-pack-file-warning-message-fix'Junio C Hamano2014-03-14
|\ \ \ \ \ | | |_|/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A warning from "git pack-objects" were generated by referring to an incorrect variable when forming the filename that we had trouble with. * sh/write-pack-file-warning-message-fix: write_pack_file: use correct variable in diagnostic
| * | | | write_pack_file: use correct variable in diagnosticSun He2014-03-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'pack_tmp_name' is the subject of the utime() check, so report it in the warning, not the uninitialized 'tmpname' Signed-off-by: Sun He <sunheehnus@gmail.com> Reviewed-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | | Merge branch 'mh/replace-refs-variable-rename'Junio C Hamano2014-03-14
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * mh/replace-refs-variable-rename: Document some functions defined in object.c Add docstrings for lookup_replace_object() and do_lookup_replace_object() rename read_replace_refs to check_replace_refs
| * | | | | rename read_replace_refs to check_replace_refsMichael Haggerty2014-02-20
| | |/ / / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The semantics of this flag was changed in commit e1111cef23 inline lookup_replace_object() calls but wasn't renamed at the time to minimize code churn. Rename it now, and add a comment explaining its use. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | | Merge branch 'nd/i18n-progress'Junio C Hamano2014-03-14
|\ \ \ \ \ | |_|_|/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mark the progress indicators from various time-consuming commands for i18n/l10n. * nd/i18n-progress: i18n: mark all progress lines for translation
| * | | | i18n: mark all progress lines for translationNguyễn Thái Ngọc Duy2014-02-24
| |/ / / | | | | | | | | | | | | | | | | Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | | Merge branch 'jk/pack-bitmap'Junio C Hamano2014-02-27
|\ \ \ \ | |/ / / |/| | / | | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Borrow the bitmap index into packfiles from JGit to speed up enumeration of objects involved in a commit range without having to fully traverse the history. * jk/pack-bitmap: (26 commits) ewah: unconditionally ntohll ewah data ewah: support platforms that require aligned reads read-cache: use get_be32 instead of hand-rolled ntoh_l block-sha1: factor out get_be and put_be wrappers do not discard revindex when re-preparing packfiles pack-bitmap: implement optional name_hash cache t/perf: add tests for pack bitmaps t: add basic bitmap functionality tests count-objects: recognize .bitmap in garbage-checking repack: consider bitmaps when performing repacks repack: handle optional files created by pack-objects repack: turn exts array into array-of-struct repack: stop using magic number for ARRAY_SIZE(exts) pack-objects: implement bitmap writing rev-list: add bitmap mode to speed up object lists pack-objects: use bitmaps when packing objects pack-objects: split add_object_entry pack-bitmap: add support for bitmap indexes documentation: add documentation for the bitmap format ewah: compressed bitmap implementation ...
| * | pack-bitmap: implement optional name_hash cacheVicent Marti2013-12-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we use pack bitmaps rather than walking the object graph, we end up with the list of objects to include in the packfile, but we do not know the path at which any tree or blob objects would be found. In a recently packed repository, this is fine. A fetch would use the paths only as a heuristic in the delta compression phase, and a fully packed repository should not need to do much delta compression. As time passes, though, we may acquire more objects on top of our large bitmapped pack. If clients fetch frequently, then they never even look at the bitmapped history, and all works as usual. However, a client who has not fetched since the last bitmap repack will have "have" tips in the bitmapped history, but "want" newer objects. The bitmaps themselves degrade gracefully in this circumstance. We manually walk the more recent bits of history, and then use bitmaps when we hit them. But we would also like to perform delta compression between the newer objects and the bitmapped objects (both to delta against what we know the user already has, but also between "new" and "old" objects that the user is fetching). The lack of pathnames makes our delta heuristics much less effective. This patch adds an optional cache of the 32-bit name_hash values to the end of the bitmap file. If present, a reader can use it to match bitmapped and non-bitmapped names during delta compression. Here are perf results for p5310: Test origin/master HEAD^ HEAD ------------------------------------------------------------------------------------------------- 5310.2: repack to disk 36.81(37.82+1.43) 47.70(48.74+1.41) +29.6% 47.75(48.70+1.51) +29.7% 5310.3: simulated clone 30.78(29.70+2.14) 1.08(0.97+0.10) -96.5% 1.07(0.94+0.12) -96.5% 5310.4: simulated fetch 3.16(6.10+0.08) 3.54(10.65+0.06) +12.0% 1.70(3.07+0.06) -46.2% 5310.6: partial bitmap 36.76(43.19+1.81) 6.71(11.25+0.76) -81.7% 4.08(6.26+0.46) -88.9% You can see that the time spent on an incremental fetch goes down, as our delta heuristics are able to do their work. And we save time on the partial bitmap clone for the same reason. Signed-off-by: Vicent Marti <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * | pack-objects: implement bitmap writingVicent Marti2013-12-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit extends more the functionality of `pack-objects` by allowing it to write out a `.bitmap` index next to any written packs, together with the `.idx` index that currently gets written. If bitmap writing is enabled for a given repository (either by calling `pack-objects` with the `--write-bitmap-index` flag or by having `pack.writebitmaps` set to `true` in the config) and pack-objects is writing a packfile that would normally be indexed (i.e. not piping to stdout), we will attempt to write the corresponding bitmap index for the packfile. Bitmap index writing happens after the packfile and its index has been successfully written to disk (`finish_tmp_packfile`). The process is performed in several steps: 1. `bitmap_writer_set_checksum`: this call stores the partial checksum for the packfile being written; the checksum will be written in the resulting bitmap index to verify its integrity 2. `bitmap_writer_build_type_index`: this call uses the array of `struct object_entry` that has just been sorted when writing out the actual packfile index to disk to generate 4 type-index bitmaps (one for each object type). These bitmaps have their nth bit set if the given object is of the bitmap's type. E.g. the nth bit of the Commits bitmap will be 1 if the nth object in the packfile index is a commit. This is a very cheap operation because the bitmap writing code has access to the metadata stored in the `struct object_entry` array, and hence the real type for each object in the packfile. 3. `bitmap_writer_reuse_bitmaps`: if there exists an existing bitmap index for one of the packfiles we're trying to repack, this call will efficiently rebuild the existing bitmaps so they can be reused on the new index. All the existing bitmaps will be stored in a `reuse` hash table, and the commit selection phase will prioritize these when selecting, as they can be written directly to the new index without having to perform a revision walk to fill the bitmap. This can greatly speed up the repack of a repository that already has bitmaps. 4. `bitmap_writer_select_commits`: if bitmap writing is enabled for a given `pack-objects` run, the sequence of commits generated during the Counting Objects phase will be stored in an array. We then use that array to build up the list of selected commits. Writing a bitmap in the index for each object in the repository would be cost-prohibitive, so we use a simple heuristic to pick the commits that will be indexed with bitmaps. The current heuristics are a simplified version of JGit's original implementation. We select a higher density of commits depending on their age: the 100 most recent commits are always selected, after that we pick 1 commit of each 100, and the gap increases as the commits grow older. On top of that, we make sure that every single branch that has not been merged (all the tips that would be required from a clone) gets their own bitmap, and when selecting commits between a gap, we tend to prioritize the commit with the most parents. Do note that there is no right/wrong way to perform commit selection; different selection algorithms will result in different commits being selected, but there's no such thing as "missing a commit". The bitmap walker algorithm implemented in `prepare_bitmap_walk` is able to adapt to missing bitmaps by performing manual walks that complete the bitmap: the ideal selection algorithm, however, would select the commits that are more likely to be used as roots for a walk in the future (e.g. the tips of each branch, and so on) to ensure a bitmap for them is always available. 5. `bitmap_writer_build`: this is the computationally expensive part of bitmap generation. Based on the list of commits that were selected in the previous step, we perform several incremental walks to generate the bitmap for each commit. The walks begin from the oldest commit, and are built up incrementally for each branch. E.g. consider this dag where A, B, C, D, E, F are the selected commits, and a, b, c, e are a chunk of simplified history that will not receive bitmaps. A---a---B--b--C--c--D \ E--e--F We start by building the bitmap for A, using A as the root for a revision walk and marking all the objects that are reachable until the walk is over. Once this bitmap is stored, we reuse the bitmap walker to perform the walk for B, assuming that once we reach A again, the walk will be terminated because A has already been SEEN on the previous walk. This process is repeated for C, and D, but when we try to generate the bitmaps for E, we can reuse neither the current walk nor the bitmap we have generated so far. What we do now is resetting both the walk and clearing the bitmap, and performing the walk from scratch using E as the origin. This new walk, however, does not need to be completed. Once we hit B, we can lookup the bitmap we have already stored for that commit and OR it with the existing bitmap we've composed so far, allowing us to limit the walk early. After all the bitmaps have been generated, another iteration through the list of commits is performed to find the best XOR offsets for compression before writing them to disk. Because of the incremental nature of these bitmaps, XORing one of them with its predecesor results in a minimal "bitmap delta" most of the time. We can write this delta to the on-disk bitmap index, and then re-compose the original bitmaps by XORing them again when loaded. This is a phase very similar to pack-object's `find_delta` (using bitmaps instead of objects, of course), except the heuristics have been greatly simplified: we only check the 10 bitmaps before any given one to find best compressing one. This gives good results in practice, because there is locality in the ordering of the objects (and therefore bitmaps) in the packfile. 6. `bitmap_writer_finish`: the last step in the process is serializing to disk all the bitmap data that has been generated in the two previous steps. The bitmap is written to a tmp file and then moved atomically to its final destination, using the same process as `pack-write.c:write_idx_file`. Signed-off-by: Vicent Marti <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * | pack-objects: use bitmaps when packing objectsVicent Marti2013-12-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In this patch, we use the bitmap API to perform the `Counting Objects` phase in pack-objects, rather than a traditional walk through the object graph. For a reasonably-packed large repo, the time to fetch and clone is often dominated by the full-object revision walk during the Counting Objects phase. Using bitmaps can reduce the CPU time required on the server (and therefore start sending the actual pack data with less delay). For bitmaps to be used, the following must be true: 1. We must be packing to stdout (as a normal `pack-objects` from `upload-pack` would do). 2. There must be a .bitmap index containing at least one of the "have" objects that the client is asking for. 3. Bitmaps must be enabled (they are enabled by default, but can be disabled by setting `pack.usebitmaps` to false, or by using `--no-use-bitmap-index` on the command-line). If any of these is not true, we fall back to doing a normal walk of the object graph. Here are some sample timings from a full pack of `torvalds/linux` (i.e. something very similar to what would be generated for a clone of the repository) that show the speedup produced by various methods: [existing graph traversal] $ time git pack-objects --all --stdout --no-use-bitmap-index \ </dev/null >/dev/null Counting objects: 3237103, done. Compressing objects: 100% (508752/508752), done. Total 3237103 (delta 2699584), reused 3237103 (delta 2699584) real 0m44.111s user 0m42.396s sys 0m3.544s [bitmaps only, without partial pack reuse; note that pack reuse is automatic, so timing this required a patch to disable it] $ time git pack-objects --all --stdout </dev/null >/dev/null Counting objects: 3237103, done. Compressing objects: 100% (508752/508752), done. Total 3237103 (delta 2699584), reused 3237103 (delta 2699584) real 0m5.413s user 0m5.604s sys 0m1.804s [bitmaps with pack reuse (what you get with this patch)] $ time git pack-objects --all --stdout </dev/null >/dev/null Reusing existing pack: 3237103, done. Total 3237103 (delta 0), reused 0 (delta 0) real 0m1.636s user 0m1.460s sys 0m0.172s Signed-off-by: Vicent Marti <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * | pack-objects: split add_object_entryJeff King2013-12-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This function actually does three things: 1. Check whether we've already added the object to our packing list. 2. Check whether the object meets our criteria for adding. 3. Actually add the object to our packing list. It's a little hard to see these three phases, because they happen linearly in the rather long function. Instead, this patch breaks them up into three separate helper functions. The result is a little easier to follow, though it unfortunately suffers from some optimization interdependencies between the stages (e.g., during step 3 we use the packing list index from step 1 and the packfile information from step 2). More importantly, though, the various parts can be composed differently, as they will be in the next patch. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * | pack-objects: factor out name_hashVicent Marti2013-10-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As the pack-objects system grows beyond the single pack-objects.c file, more parts (like the soon-to-exist bitmap code) will need to compute hashes for matching deltas. Factor out name_hash to make it available to other files. Signed-off-by: Vicent Marti <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * | pack-objects: refactor the packing listVicent Marti2013-10-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The hash table that stores the packing list for a given `pack-objects` run was tightly coupled to the pack-objects code. In this commit, we refactor the hash table and the underlying storage array into a `packing_data` struct. The functionality for accessing and adding entries to the packing list is hence accessible from other parts of Git besides the `pack-objects` builtin. This refactoring is a requirement for further patches in this series that will require accessing the commit packing list from outside of `pack-objects`. The hash table implementation has been minimally altered: we now use table sizes which are always a power of two, to ensure a uniform index distribution in the array. Signed-off-by: Vicent Marti <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | do not pretend sha1write returns errorsJeff King2013-12-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sha1write function returns an int, but it will always be "0". The failure-prone parts of the function happen in the "flush" callback, which cannot pass an error back to us. So we just end up calling die() during the flush. Let's just drop the return value altogether, as it only confuses callers into thinking that it might be useful. Only one call site actually checked the return value. We can drop that check, since it just led to a die() anyway. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | replace {pre,suf}fixcmp() with {starts,ends}_with()Christian Couder2013-12-05
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Leaving only the function definitions and declarations so that any new topic in flight can still make use of the old functions, replace existing uses of the prefixcmp() and suffixcmp() with new API functions. The change can be recreated by mechanically applying this: $ git grep -l -e prefixcmp -e suffixcmp -- \*.c | grep -v strbuf\\.c | xargs perl -pi -e ' s|!prefixcmp\(|starts_with\(|g; s|prefixcmp\(|!starts_with\(|g; s|!suffixcmp\(|ends_with\(|g; s|suffixcmp\(|!ends_with\(|g; ' on the result of preparatory changes in this series. Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | Merge branch 'jc/pack-objects'Junio C Hamano2013-10-23
|\ \ | | | | | | | | | | | | * jc/pack-objects: pack-objects: shrink struct object_entry
| * | pack-objects: shrink struct object_entryJunio C Hamano2013-02-04
| | | | | | | | | | | | | | | | | | | | | | | | Turn some boolean fields into bitfields and use uint32_t for name hash. This shrinks the size of the structure from 128 bytes to 120 bytes. Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | Merge branch 'nd/fetch-into-shallow'Junio C Hamano2013-09-20
|\ \ \ | | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When there is no sufficient overlap between old and new history during a fetch into a shallow repository, we unnecessarily sent objects the sending side knows the receiving end has. * nd/fetch-into-shallow: Add testcase for needless objects during a shallow fetch list-objects: mark more commits as edges in mark_edges_uninteresting list-objects: reduce one argument in mark_edges_uninteresting upload-pack: delegate rev walking in shallow fetch to pack-objects shallow: add setup_temporary_shallow() shallow: only add shallow graft points to new shallow file move setup_alternate_shallow and write_shallow_commits to shallow.c
| * | list-objects: reduce one argument in mark_edges_uninterestingNguyễn Thái Ngọc Duy2013-08-28
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | mark_edges_uninteresting() is always called with this form mark_edges_uninteresting(revs->commits, revs, ...); Remove the first argument and let mark_edges_uninteresting figure that out by itself. It helps answer the question "are this commit list and revs related in any way?" when looking at mark_edges_uninteresting implementation. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | Don't close pack fd when free'ing pack windowsBrandon Casey2013-08-02
|/ | | | | | | | | | | | | | | | | | | | | | | | | Now that close_one_pack() has been introduced to handle file descriptor pressure, it is not strictly necessary to close the pack file descriptor in unuse_one_window() when we're under memory pressure. Jeff King provided a justification for leaving the pack file open: If you close packfile descriptors, you can run into racy situations where somebody else is repacking and deleting packs, and they go away while you are trying to access them. If you keep a descriptor open, you're fine; they last to the end of the process. If you don't, then they disappear from under you. For normal object access, this isn't that big a deal; we just rescan the packs and retry. But if you are packing yourself (e.g., because you are a pack-objects started by upload-pack for a clone or fetch), it's much harder to recover (and we print some warnings). Let's do so (or uh, not do so). Signed-off-by: Brandon Casey <drafnel@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* Merge branch 'jk/peel-ref'Jeff King2012-10-25
|\ | | | | | | | | | | | | | | | | | | | | | | Speeds up "git upload-pack" (what is invoked by "git fetch" on the other side of the connection) by reducing the cost to advertise the branches and tags that are available in the repository. * jk/peel-ref: upload-pack: use peel_ref for ref advertisements peel_ref: check object type before loading peel_ref: do not return a null sha1 peel_ref: use faster deref_tag_noverify
| * peel_ref: do not return a null sha1Jeff King2012-10-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The idea of the peel_ref function is to dereference tag objects recursively until we hit a non-tag, and return the sha1. Conceptually, it should return 0 if it is successful (and fill in the sha1), or -1 if there was nothing to peel. However, the current behavior is much more confusing. For a regular loose ref, the behavior is as described above. But there is an optimization to reuse the peeled-ref value for a ref that came from a packed-refs file. If we have such a ref, we return its peeled value, even if that peeled value is null (indicating that we know the ref definitely does _not_ peel). It might seem like such information is useful to the caller, who would then know not to bother loading and trying to peel the object. Except that they should not bother loading and trying to peel the object _anyway_, because that fallback is already handled by peel_ref. In other words, the whole point of calling this function is that it handles those details internally, and you either get a sha1, or you know that it is not peel-able. This patch catches the null sha1 case internally and converts it into a -1 return value (i.e., there is nothing to peel). This simplifies callers, which do not need to bother checking themselves. Two callers are worth noting: - in pack-objects, a comment indicates that there is a difference between non-peelable tags and unannotated tags. But that is not the case (before or after this patch). Whether you get a null sha1 has to do with internal details of how peel_ref operated. - in show-ref, if peel_ref returns a failure, the caller tries to decide whether to try peeling manually based on whether the REF_ISPACKED flag is set. But this doesn't make any sense. If the flag is set, that does not necessarily mean the ref came from a packed-refs file with the "peeled" extension. But it doesn't matter, because even if it didn't, there's no point in trying to peel it ourselves, as peel_ref would already have done so. In other words, the fallback peeling is guaranteed to fail. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | i18n: pack-objects: mark parseopt strings for translationNguyễn Thái Ngọc Duy2012-08-20
|/ | | | | Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* Merge branch 'jc/sha1-name-more'Junio C Hamano2012-07-22
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Teaches the object name parser things like a "git describe" output is always a commit object, "A" in "git log A" must be a committish, and "A" and "B" in "git log A...B" both must be committish, etc., to prolong the lifetime of abbreviated object names. * jc/sha1-name-more: (27 commits) t1512: match the "other" object names t1512: ignore whitespaces in wc -l output rev-parse --disambiguate=<prefix> rev-parse: A and B in "rev-parse A..B" refer to committish reset: the command takes committish commit-tree: the command wants a tree and commits apply: --build-fake-ancestor expects blobs sha1_name.c: add support for disambiguating other types revision.c: the "log" family, except for "show", takes committish revision.c: allow handle_revision_arg() to take other flags sha1_name.c: introduce get_sha1_committish() sha1_name.c: teach lookup context to get_sha1_with_context() sha1_name.c: many short names can only be committish sha1_name.c: get_sha1_1() takes lookup flags sha1_name.c: get_describe_name() by definition groks only commits sha1_name.c: teach get_short_sha1() a commit-only option sha1_name.c: allow get_short_sha1() to take other flags get_sha1(): fix error status regression sha1_name.c: restructure disambiguation of short names sha1_name.c: correct misnamed "canonical" and "res" ...
| * revision.c: allow handle_revision_arg() to take other flagsJunio C Hamano2012-07-09
| | | | | | | | | | | | | | | | | | The existing "cant_be_filename" that tells the function that the caller knows the arg is not a path (hence it does not have to be checked for absense of the file whose name matches it) is made into a bit in the flag word. Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | pack-objects: use streaming interface for reading large loose blobsNguyễn Thái Ngọc Duy2012-05-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git usually streams large blobs directly to packs. But there are cases where git can create large loose blobs (unpack-objects or hash-object over pipe). Or they can come from other git implementations. core.bigfilethreshold can also be lowered down and introduce a new wave of large loose blobs. Use streaming interface to read/compress/write these blobs in one go. Fall back to normal way if somehow streaming interface cannot be used. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | pack-objects: refactor write_object() into helper functionsNguyễn Thái Ngọc Duy2012-05-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function first decides if we want to copy data taken from existing pack verbatim or we want to encode the data ourselves for the packfile we are creating and then carries out the decision. Separate the latter phase into two helper functions, one for the case the data is reused, the other for the case the data is produced anew. A little twist is that it can later turn out that we cannot reuse the data after we initially decide to do so; in such a case, the "reuse" helper makes a call to "generate" helper. It is easier to follow than the current fallback code that uses "goto" inside a single large function. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | pack-objects, streaming: turn "xx >= big_file_threshold" to ".. > .."Nguyễn Thái Ngọc Duy2012-05-18
| | | | | | | | | | | | | | This is because all other places do "xx > big_file_threshold" Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | gc: do not explode objects which will be immediately prunedJeff King2012-04-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we pack everything into one big pack with "git repack -Ad", any unreferenced objects in to-be-deleted packs are exploded into loose objects, with the intent that they will be examined and possibly cleaned up by the next run of "git prune". Since the exploded objects will receive the mtime of the pack from which they come, if the source pack is old, those loose objects will end up pruned immediately. In that case, it is much more efficient to skip the exploding step entirely for these objects. This patch teaches pack-objects to receive the expiration information and avoid writing these objects out. It also teaches "git gc" to pass the value of gc.pruneexpire to repack (which in turn learns to pass it along to pack-objects) so that this optimization happens automatically during "git gc" and "git gc --auto". Signed-off-by: Jeff King <peff@peff.net> Acked-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | pack-objects: Fix compilation with NO_PTHREDSMichał Kiedrowicz2012-02-26
| | | | | | | | | | | | | | | | | | | | It looks like commit 99fb6e04 (pack-objects: convert to use parse_options(), 2012-02-01) moved the #ifdef NO_PTHREDS around but hasn't noticed that the 'arg' variable no longer is available. Signed-off-by: Michał Kiedrowicz <michal.kiedrowicz@gmail.com> Acked-by: Nguyen Thai Ngoc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | pack-objects: convert to use parse_options()Nguyễn Thái Ngọc Duy2012-02-01
| | | | | | | | | | Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | pack-objects: remove bogus commentNguyễn Thái Ngọc Duy2012-02-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The comment was introduced in b5d97e6 (pack-objects: run rev-list equivalent internally. - 2006-09-04), stating that git pack-objects [options] base-name <refs...> is acceptable and refs should be passed into rev-list. But that's not true. All arguments after base-name are ignored. Remove the comment and reject this syntax (i.e. no more arguments after base name) Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>