git/cache-tree.c, branch v2.31.7

use CALLOC_ARRAY

2021-03-14T00:00:09Z

Add and apply a semantic patch for converting code that open-codes CALLOC_ARRAY to use it instead. It shortens the code and infers the element size automatically. Signed-off-by: René Scharfe Signed-off-by: Junio C Hamano

cache-tree: extract subtree_pos()

2021-01-24T01:14:07Z

This method will be helpful to use outside of cache-tree.c in a later feature. The implementation is subtle due to subtree_name_cmp() sorting by length and then lexicographically. Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

cache-tree: simplify verify_cache() prototype

2021-01-24T01:14:07Z

The verify_cache() method takes an array of cache entries and a count, but these are always provided directly from a struct index_state. Use a pointer to the full structure instead. There is a subtle point when istate->cache_nr is zero that subtracting one will underflow. This triggers a failure in t0000-basic.sh, among others. Use "i + 1 < istate->cache_nr" to avoid these strange comparisons. Convert i to be unsigned as well, which also removes the potential signed overflow in the unlikely case that cache_nr is over 2.1 billion entries. The 'funny' variable has a maximum value of 11, so making it unsigned does not change anything of importance. Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

cache-tree: clean up cache_tree_update()

2021-01-24T01:14:07Z

Make the method safer by allocating a cache_tree member for the given index_state if it is not already present. This is preferrable to a BUG() statement or returning with an error because future callers will want to populate an empty cache-tree using this method. Callers can also remove their conditional allocations of cache_tree. Also drop local variables that can be found directly from the 'istate' parameter. Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

cache-tree: speed up consecutive path comparisons

2021-01-16T07:05:13Z

The previous change reduced time spent in strlen() while comparing consecutive paths in verify_cache(), but we can do better. The conditional checks the existence of a directory separator at the correct location, but only after doing a string comparison. Swap the order to be logically equivalent but perform fewer string comparisons. To test the effect on performance, I used a repository with over three million paths in the index. I then ran the following command on repeat: git -c index.threads=1 commit --amend --allow-empty --no-edit Here are the measurements over 10 runs after a 5-run warmup: Benchmark #1: v2.30.0 Time (mean ± σ): 854.5 ms ± 18.2 ms Range (min … max): 825.0 ms … 892.8 ms Benchmark #2: Previous change Time (mean ± σ): 833.2 ms ± 10.3 ms Range (min … max): 815.8 ms … 849.7 ms Benchmark #3: This change Time (mean ± σ): 815.5 ms ± 18.1 ms Range (min … max): 795.4 ms … 849.5 ms This change is 2% faster than the previous change and 5% faster than v2.30.0. Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

cache-tree: use ce_namelen() instead of strlen()

2021-01-16T07:05:13Z

Use the name length field of cache entries instead of calculating its value anew. Signed-off-by: René Scharfe Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

cache-tree: trace regions for prime_cache_tree

2021-01-16T07:04:32Z

Commands such as "git reset --hard" rebuild the in-memory representation of the cache tree index extension by parsing tree objects starting at a known root tree. The performance of this operation can vary widely depending on the width and depth of the repository's working directory structure. Measure the time in this operation using trace2 regions in prime_cache_tree(). Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

cache-tree: trace regions for I/O

2021-01-16T07:04:21Z

As we write or read the cache tree index extension, it can be good to isolate how much of the file I/O time is spent constructing this in-memory tree from the existing index or writing it out again to the new index file. Use trace2 regions to indicate that we are spending time on this operation. Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

cache-tree: use trace2 in cache_tree_update()

2021-01-04T23:23:08Z

This matches a trace_performance_enter()/trace_performance_leave() pair added by 0d1ed59 (unpack-trees: add performance tracing, 2018-08-18). Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

sha1-file: pass git_hash_algo to hash_object_file()

2020-01-31T18:45:39Z

Allow hash_object_file() to work on arbitrary repos by introducing a git_hash_algo parameter. Change callers which have a struct repository pointer in their scope to pass on the git_hash_algo from the said repo. For all other callers, pass on the_hash_algo, which was already being used internally at hash_object_file(). This functionality will be used in the following patch to make check_object_signature() be able to work on arbitrary repos (which, in turn, will be used to fix an inconsistency at object.c:parse_object()). Signed-off-by: Matheus Tavares Signed-off-by: Junio C Hamano