Goal ~~~~ This is a patch series about libifying `git apply` functionality, and using this libified functionality in `git am`, so that no 'git apply' process is spawn anymore. This makes `git am` significantly faster, so `git rebase`, when it uses the am backend, is also significantly faster. Previous discussions and patches series ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This has initially been discussed in the following thread: http://thread.gmane.org/gmane.comp.version-control.git/287236/ Then the following patch series were sent: RFC: http://thread.gmane.org/gmane.comp.version-control.git/288489/ v1: http://thread.gmane.org/gmane.comp.version-control.git/292324/ v2: http://thread.gmane.org/gmane.comp.version-control.git/294248/ v3: http://thread.gmane.org/gmane.comp.version-control.git/295429/ v4: http://thread.gmane.org/gmane.comp.version-control.git/296350/ v5: http://thread.gmane.org/gmane.comp.version-control.git/296490/ v6: http://thread.gmane.org/gmane.comp.version-control.git/297024/ v7: http://thread.gmane.org/gmane.comp.version-control.git/297193/ v8: https://public-inbox.org/git/20160627182429.31550-1-chriscool%40tuxfamily.org/ v9: https://public-inbox.org/git/20160730172509.22939-1-chriscool%40tuxfamily.org/ v10: https://public-inbox.org/git/20160808210337.5038-1-chriscool%40tuxfamily.org/ v11: https://public-inbox.org/git/20160811085229.19017-1-chriscool%40tuxfamily.org/ v12: https://public-inbox.org/git/20160811184501.384-1-chriscool@xxxxxxxxxxxxx/ v13: https://public-inbox.org/git/20160827184547.4365-1-chriscool@xxxxxxxxxxxxx/ Highlevel view of the patches in the series ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This is "part 2" of the full patch series. I am resending everything that is not already in master to give people another chance to review everything. - Patch 01/41 to 27/41 were in v10, but not in v11, v12, and v13. They libify the apply functions by making them return error codes instead of die()ing or exit()ing and by making sure they release all the resources they use. There is only one change in patch 26/41 where I now use error_errno() right away instead of first using error() and then converting the error() into error_errno() in patch 32/41. - Patches 28/41 to 31/41 were in v12 and v13. They finish libifying the apply functionality that was in builtin/apply.c and move it into apply.{c,h}, but the libified functionality is not yet used in `git am`. In patch 29/41 I added some comments in apply.h above the definition of APPLY_OPT_INACCURATE_EOF and APPLY_OPT_RECOUNT, as suggested by Stefan. This is the only change compared to v13. - Patch 32/41 was in v10, v12 and v13. It replaces some calls to error() with calls to error_errno(). One hunk has been removed because of the changes in 26/41. - Patches 33/41 to 37/41 were in v10, v12 and v13. They implement a way to make the libified apply code silent by changing the bool `apply_verbosely` into a tristate enum called `apply_verbosity`, that can be one of `verbosity_verbose`, `verbosity_normal` or `verbosity_silent`. The only changes since v13 are in 37/41. The name of the first argument to mute_routine() is changed from "bla" to "msg" as suggested by Ramsey, and the commit message is improved as suggested by Stefan. - Patch 38/41 was in v10, v12 and v13, and hasn't changed. It refactors `git apply` option parsing to make it possible for `git am` to easily pass some command line options to the libified applied code. - Patch 39/41 was new in v13, and hasn't changed. It is a refactoring to prepare for patch 40/41. - Patch 40/41 was in v12 and v13, and hasn't changed. It adds a "const char *index_file" into "struct apply_state", to make it possible to use a special index file instead of the default one. - Patch 41/41 was in v10, v12 and v13. This patch makes `git am` use the libified functionality. The only change compared to v13 is that "through" instead of "thru" is used in an error message. General comments ~~~~~~~~~~~~~~~~ Now this patch series is 41 patches long to give yet another possibility for all the patches to be reviewed. I took another look at all these patches myself and didn't find anything other than the changes I made in 26/41 to improve. I will send a diff between this version and v13 as a reply to this email. The benefits are not just related to not creating new processes. When `git am` launched a `git apply` process, this new process had to read the index from disk. Then after the `git apply`process had terminated, `git am` dropped its index and read the index from disk to get the index that had been modified by the `git apply`process. This was inefficient and also prevented the split-index mechanism to provide many performance benefits. By the way, current work is ongoing to make it possible to use split-index more easily by adding a config variable, see: https://public-inbox.org/git/20160711172254.13439-1-chriscool%40tuxfamily.org/ Using an earlier version of this series as rebase material, Duy explained split-index benefits along with this patch series like this: > Without the series, the picture is not so surprising. We run git-apply > 80+ times, each consists of this sequence > > read index > write index (cache tree updates only) > read index again > optionally initialize name hash (when new entries are added, I guess) > read packed-refs > write index > > With this series, we run a single git-apply which does > > read index (and sharedindex too if in split-index mode) > initialize name hash > write index 80+ times (See: http://thread.gmane.org/gmane.comp.version-control.git/292324/focus=292460) Links ~~~~~ This patch series is available here: https://github.com/chriscool/git/commits/libify-apply-use-in-am The previous versions are available there: v1: https://github.com/chriscool/git/commits/libify-apply-use-in-am25 v2: https://github.com/chriscool/git/commits/libify-apply-use-in-am54 v6: https://github.com/chriscool/git/commits/libify-apply-use-in-am65 v7: https://github.com/chriscool/git/commits/libify-apply-use-in-am75 v8: https://github.com/chriscool/git/commits/libify-apply-use-in-am97 v9: https://github.com/chriscool/git/commits/libify-apply-use-in-am106 v10: https://github.com/chriscool/git/commits/libify-apply-use-in-am114 v11: https://github.com/chriscool/git/commits/libify-apply-use-in-am116 v12: https://github.com/chriscool/git/commits/libify-apply-use-in-am118 v13: https://github.com/chriscool/git/commits/libify-apply-use-in-am120 Performance numbers ~~~~~~~~~~~~~~~~~~~ Numbers are only available for tests that have been performed on Linux using a very early version of this series, though Johannes Sixt reported great improvements on Windows. It could be interesting to get detailed numbers on other platforms like Windows and OSX. - Around mid April Ævar did a huge many-hundred commit rebase on the kernel with untracked cache. command: git rebase --onto 1993b17 52bef0c 29dde7c Vanilla "next" without split index: 1m54.953s Vanilla "next" with split index: 1m22.476s This series on top of "next" without split index: 1m12.034s This series on top of "next" with split index: 0m15.678s Ævar used his Debian laptop with SSD. - Around mid April I tested rebasing 13 commits in Booking.com's monorepo on a Red Hat 6.5 server with split-index and GIT_TRACE_PERFORMANCE=1. With Git v2.8.0, the rebase took 6.375888383 s, with the git am command launched by the rebase command taking 3.705677431 s. With this series on top of next, the rebase took 3.044529494 s, with the git am command launched by the rebase command taking 0.583521168 s. Christian Couder (41): apply: make some names more specific apply: move 'struct apply_state' to apply.h builtin/apply: make apply_patch() return -1 or -128 instead of die()ing builtin/apply: read_patch_file() return -1 instead of die()ing builtin/apply: make find_header() return -128 instead of die()ing builtin/apply: make parse_chunk() return a negative integer on error builtin/apply: make parse_single_patch() return -1 on error builtin/apply: make parse_whitespace_option() return -1 instead of die()ing builtin/apply: make parse_ignorewhitespace_option() return -1 instead of die()ing builtin/apply: move init_apply_state() to apply.c apply: make init_apply_state() return -1 instead of exit()ing builtin/apply: make check_apply_state() return -1 instead of die()ing builtin/apply: move check_apply_state() to apply.c builtin/apply: make apply_all_patches() return 128 or 1 on error builtin/apply: make parse_traditional_patch() return -1 on error builtin/apply: make gitdiff_*() return 1 at end of header builtin/apply: make gitdiff_*() return -1 on error builtin/apply: change die_on_unsafe_path() to check_unsafe_path() builtin/apply: make build_fake_ancestor() return -1 on error builtin/apply: make remove_file() return -1 on error builtin/apply: make add_conflicted_stages_file() return -1 on error builtin/apply: make add_index_file() return -1 on error builtin/apply: make create_file() return -1 on error builtin/apply: make write_out_one_result() return -1 on error builtin/apply: make write_out_results() return -1 on error builtin/apply: make try_create_file() return -1 on error builtin/apply: make create_one_file() return -1 on error builtin/apply: rename option parsing functions apply: rename and move opt constants to apply.h Move libified code from builtin/apply.c to apply.{c,h} apply: make some parsing functions static again apply: use error_errno() where possible apply: make it possible to silently apply apply: don't print on stdout in verbosity_silent mode usage: add set_warn_routine() usage: add get_error_routine() and get_warn_routine() apply: change error_routine when silent apply: refactor `git apply` option parsing apply: pass apply state to build_fake_ancestor() apply: learn to use a different index file builtin/am: use apply API in run_apply() Makefile | 1 + apply.c | 4988 ++++++++++++++++++++++++++++++++++++++++++++++++ apply.h | 137 ++ builtin/am.c | 65 +- builtin/apply.c | 4873 +--------------------------------------------- git-compat-util.h | 3 + t/t4012-diff-binary.sh | 4 +- t/t4254-am-corrupt.sh | 2 +- usage.c | 15 + 9 files changed, 5205 insertions(+), 4883 deletions(-) create mode 100644 apply.c create mode 100644 apply.h -- 2.10.0.41.g9df52c3