[PATCH 0/9] Expose the submodule parallelism to the user

Where does it apply? --- This applies on 376d400f4c (run-command: fix missing output from late callbacks, which is the latest commit in origin/sb/submodule-parallel-fetch which was merged to origin/next) The first patch is a duplicate of origin/sb/submodule-config-parse, so it may make sense to drop the first patch and apply this series on top of a merge of 376d400f4c and origin/sb/submodule-config-parse.

I realize sending refactorings in the area you'd be likely to touch as a separate patch (series) is not necessarily a good idea as it leads to situations like this.

What does it do? --- This series should finish the on going efforts of parallelizing submodule network traffic. The patches contain tests for clone, fetch and submodule update to use the actual parallelism both via command line as well as a configured option. I decided to go with "submodule.jobs" for all three for now.

Detailed breakdown of the patches ---

Patch 1 is a duplicate of origin/sb/submodule-config-parse and may make merging with that easier.

Patch 2 adds the update strategy to the struct submodule, which is required in patch 4.

Patch 3 adds rudimentary tracing output to the parallel processing commands.

Patch 4 rewrites parts of "git submodule update" in C, such that the cloning is done from within the parallel processing engine.

Patch 5 however exposes the possible parallelism of patch 4 to the user. (doc + tests)

Patch 6 adds the parallel feature to clone, which just invokes "submodule update" internally.

Patch 7 is a small refactoring preparing patch 8 to smoothly parse submodules.jobs.

Patch 9 teaches fetch to respect the desired parallelism both from command line as well as the config option.

Thanks, Stefan

Stefan Beller (9):
  submodule-config: "goto" removal in parse_config()
  submodule config: keep update strategy around
  run_processes_parallel: Add output to tracing messages
  git submodule update: have a dedicated helper for cloning
  submodule update: expose parallelism to the user
  clone: allow an explicit argument for parallel submodule clones
  submodule config: remove name_and_item_from_var
  submodule-config: parse_config
  fetching submodules: Respect `submodule.jobs` config option

 Documentation/config.txt        |   7 ++
 Documentation/git-clone.txt     |   5 +-
 Documentation/git-submodule.txt |   6 +-
 builtin/clone.c                 |  26 ++++-
 builtin/fetch.c                 |   2 +-
 builtin/submodule--helper.c     | 243 ++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh                |  54 ++++-----
 run-command.c                   |   4 +
 submodule-config.c              | 166 ++++++++++++++-------------
 submodule-config.h              |   3 +
 submodule.c                     |   5 +
 t/t5526-fetch-submodules.sh     |  14 +++
 t/t7400-submodule-basic.sh      |   4 +-
 t/t7406-submodule-update.sh     |  27 +++++
 14 files changed, 444 insertions(+), 122 deletions(-)