# \[PATCH 0/5\] \[GSOC\] \[RFC\] ref-filter: performance optimization

- From: ZheNing Hu via GitGitGadget \<hidden\>
- Date: 2021-08-17 07:14:55 
- List: git
- Page: https://ratatoskr.run/git/2021/08/7899475
- Thread: https://ratatoskr.run/git/2021/08/7899475/t.md

```text
Last time I submitted a very long patch series:
https://lore.kernel.org/git/pull.1016.git.1628842990.gitgitgadget@gmail.com/
My mentor Christian suggested to split the performance optimization part
out, so this patch series used to optimize performance optimization in
ref-filter.

Changes in this patch series:

 1. Skip parse_object_buffer(), which can reduce object content parsing.
 2. Use linked list to record parsing results, which can reduce second
    format string parsing.
 3. Reuse final buffer, which can reduce memcpy();
 4. Add a need_get_object_info flag instead of compare two object_info,
    which can reduce memcmp();
 5. Use ALLOC_ARRAY() instead of CALLOC_ARRAY(), which can reduce memset();

Since the relevant part of git cat-file --batch has been deleted, the
execution time of git for-each-ref is very short, I haven’t added
performance tests yet for git for-each-ref.

ZheNing Hu (5):
  [GSOC] ref-filter: skip parse_object_buffer in some cases
  [GSOC] ref-filter: remove second parsing in format_ref_array_item
  [GSOC] ref-filter: reuse final buffer
  [GSOC] ref-filter: reduce unnecessary object_info comparisons
  [GSOC]: ref-filter: instead CALLOC_ARRAY to ALLOC_ARRAY

 builtin/branch.c       |   2 +
 builtin/for-each-ref.c |   3 +-
 builtin/tag.c          |   2 +
 builtin/verify-tag.c   |   2 +
 ref-filter.c           | 168 ++++++++++++++++++++++++++++++++---------
 ref-filter.h           |  17 ++++-
 6 files changed, 154 insertions(+), 40 deletions(-)


base-commit: f000ecbed922c727382651490e75014f003c89ca
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1020%2Fadlternative%2Fref-filter-opt-perf-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1020/adlternative/ref-filter-opt-perf-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1020
-- 
gitgitgadget
```