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authorElijah Newren <newren@gmail.com>2021-07-30 11:47:37 (GMT)
committerJunio C Hamano <gitster@pobox.com>2021-07-30 16:01:18 (GMT)
commitfa0e936fbb683dbce70b797ae8a5be6b88f48d88 (patch)
treeedf07ff60d6aa56feedc1992578cd82c03a0c4e4
parent7afc0b03a2307aa02b7caff2746664e886f38d9a (diff)
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diffcore-rename: use a mem_pool for exact rename detection's hashmap
Exact rename detection, via insert_file_table(), uses a hashmap to store files by oid. Use a mem_pool for the hashmap entries so these can all be allocated and deallocated together. For the testcases mentioned in commit 557ac0350d ("merge-ort: begin performance work; instrument with trace2_region_* calls", 2020-10-28), this change improves the performance as follows: Before After no-renames: 204.2 ms ± 3.0 ms 202.5 ms ± 3.2 ms mega-renames: 1.076 s ± 0.015 s 1.072 s ± 0.012 s just-one-mega: 364.1 ms ± 7.0 ms 357.3 ms ± 3.9 ms Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--diffcore-rename.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/diffcore-rename.c b/diffcore-rename.c
index 4ef0459..73d8840 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -317,10 +317,11 @@ static int find_identical_files(struct hashmap *srcs,
}
static void insert_file_table(struct repository *r,
+ struct mem_pool *pool,
struct hashmap *table, int index,
struct diff_filespec *filespec)
{
- struct file_similarity *entry = xmalloc(sizeof(*entry));
+ struct file_similarity *entry = mem_pool_alloc(pool, sizeof(*entry));
entry->index = index;
entry->filespec = filespec;
@@ -336,7 +337,8 @@ static void insert_file_table(struct repository *r,
* and then during the second round we try to match
* cache-dirty entries as well.
*/
-static int find_exact_renames(struct diff_options *options)
+static int find_exact_renames(struct diff_options *options,
+ struct mem_pool *pool)
{
int i, renames = 0;
struct hashmap file_table;
@@ -346,7 +348,7 @@ static int find_exact_renames(struct diff_options *options)
*/
hashmap_init(&file_table, NULL, NULL, rename_src_nr);
for (i = rename_src_nr-1; i >= 0; i--)
- insert_file_table(options->repo,
+ insert_file_table(options->repo, pool,
&file_table, i,
rename_src[i].p->one);
@@ -354,8 +356,8 @@ static int find_exact_renames(struct diff_options *options)
for (i = 0; i < rename_dst_nr; i++)
renames += find_identical_files(&file_table, i, options);
- /* Free the hash data structure and entries */
- hashmap_clear_and_free(&file_table, struct file_similarity, entry);
+ /* Free the hash data structure (entries will be freed with the pool) */
+ hashmap_clear(&file_table);
return renames;
}
@@ -1341,6 +1343,7 @@ void diffcore_rename_extended(struct diff_options *options,
int num_destinations, dst_cnt;
int num_sources, want_copies;
struct progress *progress = NULL;
+ struct mem_pool local_pool;
struct dir_rename_info info;
struct diff_populate_filespec_options dpf_options = {
.check_binary = 0,
@@ -1409,11 +1412,18 @@ void diffcore_rename_extended(struct diff_options *options,
goto cleanup; /* nothing to do */
trace2_region_enter("diff", "exact renames", options->repo);
+ mem_pool_init(&local_pool, 32*1024);
/*
* We really want to cull the candidates list early
* with cheap tests in order to avoid doing deltas.
*/
- rename_count = find_exact_renames(options);
+ rename_count = find_exact_renames(options, &local_pool);
+ /*
+ * Discard local_pool immediately instead of at "cleanup:" in order
+ * to reduce maximum memory usage; inexact rename detection uses up
+ * a fair amount of memory, and mem_pools can too.
+ */
+ mem_pool_discard(&local_pool, 0);
trace2_region_leave("diff", "exact renames", options->repo);
/* Did we only want exact renames? */