Some commits modify the same set of paths, and, consequently, have
identical modified path Bloom filters.
Use a hashmap to find these identical Bloom filters, and omit all
duplicates from the Modified Path Bloom Filters chunk, reducing its
size.
MPBF chunk size
without with Time spent
deduplication deduping
--------------------------------------------------------
android-base 8620198 2618764 -69.6% 0.089s
cmssw 10347018 9094468 -12.1% 0.056s
cpython 526381 371629 -29.4% 0.013s
elasticsearch 4733274 3607106 -23.8% 0.029s
gcc 3724544 3394521 -8.9% 0.072s
gecko-dev 20591010 17042732 -17.2% 0.235s
git 160718 139546 -13.2% 0.004s
glibc 759132 699623 -7.8% 0.009s
go 458375 421394 -8.1% 0.008s
jdk 13213208 12158533 -8.0% 0.034s
linux 26575278 25029700 -5.8% 0.169s
llvm-project 3988133 3269438 -18.0% 0.085s
rails 958691 614528 -35.9% 0.015s
rust 1985782 1682919 -15.3% 0.023s
tensorflow 4173570 3789768 -9.2% 0.022s
webkit 5891751 5394507 -8.4% 0.096s
Signed-off-by: SZEDER Gábor <szeder.dev@xxxxxxxxx>
---
commit-graph.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 71 insertions(+), 5 deletions(-)
diff --git a/commit-graph.c b/commit-graph.c
index 56b8f33d10..178bbf0113 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -57,6 +57,7 @@
struct modified_path_bloom_filter_info {
struct bloom_filter filter;
+ struct modified_path_bloom_filter_info *duplicate_of;
/*
* The offset relative to the start of the Modified Path Bloom
* Filters chunk where this Bloom filter has been written,
@@ -1099,6 +1100,9 @@ struct write_commit_graph_context {
/* Excluding embedded modified path Bloom filters */
uint64_t total_filter_size;
+
+ /* Used to find identical modified path Bloom filters */
+ struct hashmap dedup_hashmap;
} mpbfctx;
};
@@ -1315,7 +1319,11 @@ static int write_graph_chunk_modified_path_bloom_filters(struct hashfile *f,
bfi = modified_path_bloom_filters_peek(
&modified_path_bloom_filters, commit);
- if (!bfi || !bfi->filter.nr_bits)
+ if (!bfi)
+ continue;
+ if (bfi->duplicate_of)
+ continue;
+ if (!bfi->filter.nr_bits)
continue;
if (bfi->filter.nr_bits == GRAPH_MODIFIED_PATH_BLOOM_FILTER_EMBEDDED_NR_BITS)
continue;
@@ -1364,6 +1372,9 @@ static int write_graph_chunk_modified_path_bloom_index(struct hashfile *f,
*/
filterdata[0] |= 1 << 7;
hashwrite(f, filterdata, sizeof(filterdata));
+ } else if (bfi->duplicate_of) {
+ uint64_t offset = htonll(bfi->duplicate_of->offset);
+ hashwrite(f, &offset, sizeof(offset));
} else if (bfi->offset != -1) {
uint64_t offset = htonll(bfi->offset);
hashwrite(f, &offset, sizeof(offset));
@@ -1515,6 +1526,53 @@ static void file_change_cb(struct diff_options *options,
handle_modified_file(options->change_fn_data, fullpath);
}
+struct modified_path_bloom_filter_dedup_entry {
+ struct hashmap_entry entry;
+ struct modified_path_bloom_filter_info *bfi;
+};
+
+static int modified_path_bloom_filter_dedup_cmp(const void *unused_cmp_data,
+ const struct hashmap_entry *he1,
+ const struct hashmap_entry *he2,
+ const void *unused_keydata)
+{
+ const struct modified_path_bloom_filter_dedup_entry *a, *b;
+
+ a = container_of(he1, const struct modified_path_bloom_filter_dedup_entry, entry);
+ b = container_of(he2, const struct modified_path_bloom_filter_dedup_entry, entry);
+
+ if (a->bfi->filter.nr_bits != b->bfi->filter.nr_bits)
+ return 1;
+
+ return memcmp(a->bfi->filter.bits, b->bfi->filter.bits,
+ bloom_filter_bytes(&a->bfi->filter));
+}
+
+static int handle_duplicate_modified_path_bloom_filter(
+ struct modified_path_bloom_filter_context *mpbfctx,
+ struct modified_path_bloom_filter_info *bfi)
+{
+ struct modified_path_bloom_filter_dedup_entry *e, stack_entry;
+ unsigned int h;
+
+ h = memhash(bfi->filter.bits, bloom_filter_bytes(&bfi->filter));
+ hashmap_entry_init(&stack_entry.entry, h);
+ stack_entry.bfi = bfi;
+
+ e = hashmap_get_entry(&mpbfctx->dedup_hashmap, &stack_entry, entry,
+ NULL);
+ if (e) {
+ bfi->duplicate_of = e->bfi;
+ return 1;
+ } else {
+ e = xmalloc(sizeof(*e));
+ hashmap_entry_init(&e->entry, h);
+ e->bfi = bfi;
+ hashmap_add(&mpbfctx->dedup_hashmap, &e->entry);
+ return 0;
+ }
+}
+
static void create_modified_path_bloom_filter(
struct modified_path_bloom_filter_context *mpbfctx,
struct commit *commit)
@@ -1547,17 +1605,20 @@ static void create_modified_path_bloom_filter(
bfi = modified_path_bloom_filters_at(&modified_path_bloom_filters,
commit);
bfi->offset = -1;
- if (path_component_count > mpbfctx->embedded_limit) {
+ if (path_component_count > mpbfctx->embedded_limit)
bloom_filter_init(&bfi->filter, mpbfctx->num_hashes,
path_component_count);
- mpbfctx->total_filter_size += sizeof(uint32_t) +
- bloom_filter_bytes(&bfi->filter);
- } else
+ else
bloom_filter_init_with_size(&bfi->filter,
GRAPH_MODIFIED_PATH_BLOOM_FILTER_EMBEDDED_NR_BITS);
bloom_filter_set_bits(&bfi->filter, mpbfctx->hashes,
mpbfctx->hashes_nr);
+
+ if (path_component_count > mpbfctx->embedded_limit &&
+ !handle_duplicate_modified_path_bloom_filter(mpbfctx, bfi))
+ mpbfctx->total_filter_size += sizeof(uint32_t) +
+ bloom_filter_bytes(&bfi->filter);
}
static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
@@ -2396,6 +2457,8 @@ int write_commit_graph(const char *obj_dir,
diff_setup_done(&ctx->mpbfctx.diffopt);
strbuf_init(&ctx->mpbfctx.prev_path, PATH_MAX);
+ hashmap_init(&ctx->mpbfctx.dedup_hashmap,
+ modified_path_bloom_filter_dedup_cmp, NULL, 0);
}
if (ctx->split) {
@@ -2525,6 +2588,9 @@ int write_commit_graph(const char *obj_dir,
strbuf_release(&ctx->mpbfctx.prev_path);
free(ctx->mpbfctx.hashed_prefix_lengths);
free(ctx->mpbfctx.hashes);
+ hashmap_free_entries(&ctx->mpbfctx.dedup_hashmap,
+ struct modified_path_bloom_filter_dedup_entry,
+ entry);
}
free(ctx);
--
2.27.0.rc1.431.g5c813f95dc
