From d21ee7d111073dfd7a86f6fe870d0c1ec6a07126 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Mon, 30 Mar 2020 00:31:29 +0000 Subject: [PATCH] commit-graph: examine changed-path objects in pack order Looking at the diff of commit objects in pack order is much faster than in sha1 order, as it gives locality to the access of tree deltas (whereas sha1 order is effectively random). Unfortunately the commit-graph code sorts the commits (several times, sometimes as an oid and sometimes a pointer-to-commit), and we ultimately traverse in sha1 order. Instead, let's remember the position at which we see each commit, and traverse in that order when looking at bloom filters. This drops my time for "git commit-graph write --changed-paths" in linux.git from ~4 minutes to ~1.5 minutes. Probably the "--reachable" code path would want something similar. Or alternatively, we could use a different data structure (either a hash, or maybe even just a bit in "struct commit") to keep track of which oids we've seen, etc instead of sorting. And then we could keep the original order. Signed-off-by: Jeff King Signed-off-by: Garima Singh Signed-off-by: Junio C Hamano --- commit-graph.c | 38 +++++++++++++++++++++++++++++++++++--- 1 file changed, 35 insertions(+), 3 deletions(-) diff --git a/commit-graph.c b/commit-graph.c index 862a00d67e..31b06f878c 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -17,6 +17,7 @@ #include "replace-object.h" #include "progress.h" #include "bloom.h" +#include "commit-slab.h" #define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */ #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */ @@ -46,9 +47,32 @@ /* Remember to update object flag allocation in object.h */ #define REACHABLE (1u<<15) -char *get_commit_graph_filename(struct object_directory *odb) +/* Keep track of the order in which commits are added to our list. */ +define_commit_slab(commit_pos, int); +static struct commit_pos commit_pos = COMMIT_SLAB_INIT(1, commit_pos); + +static void set_commit_pos(struct repository *r, const struct object_id *oid) { - return xstrfmt("%s/info/commit-graph", odb->path); + static int32_t max_pos; + struct commit *commit = lookup_commit(r, oid); + + if (!commit) + return; /* should never happen, but be lenient */ + + *commit_pos_at(&commit_pos, commit) = max_pos++; +} + +static int commit_pos_cmp(const void *va, const void *vb) +{ + const struct commit *a = *(const struct commit **)va; + const struct commit *b = *(const struct commit **)vb; + return commit_pos_at(&commit_pos, a) - + commit_pos_at(&commit_pos, b); +} + +char *get_commit_graph_filename(struct object_directory *obj_dir) +{ + return xstrfmt("%s/info/commit-graph", obj_dir->path); } static char *get_split_graph_filename(struct object_directory *odb, @@ -1021,6 +1045,8 @@ static int add_packed_commits(const struct object_id *oid, oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid); ctx->oids.nr++; + set_commit_pos(ctx->r, oid); + return 0; } @@ -1141,6 +1167,7 @@ static void compute_bloom_filters(struct write_commit_graph_context *ctx) { int i; struct progress *progress = NULL; + struct commit **sorted_commits; init_bloom_filters(); @@ -1149,13 +1176,18 @@ static void compute_bloom_filters(struct write_commit_graph_context *ctx) _("Computing commit changed paths Bloom filters"), ctx->commits.nr); + ALLOC_ARRAY(sorted_commits, ctx->commits.nr); + COPY_ARRAY(sorted_commits, ctx->commits.list, ctx->commits.nr); + QSORT(sorted_commits, ctx->commits.nr, commit_pos_cmp); + for (i = 0; i < ctx->commits.nr; i++) { - struct commit *c = ctx->commits.list[i]; + struct commit *c = sorted_commits[i]; struct bloom_filter *filter = get_bloom_filter(ctx->r, c); ctx->total_bloom_filter_data_size += sizeof(unsigned char) * filter->len; display_progress(progress, i + 1); } + free(sorted_commits); stop_progress(&progress); }