midx.c: instrument MIDX and bitmap generation with trace2 regions

When debugging MIDX and MIDX-bitmap related issues, it is useful to
figure out where Git is spending its time.

GitHub has been using the below trace2 regions to instrument various
components of generating a MIDX itself, as well time spent preparing to
build a MIDX bitmap.

These are limited to instrumenting the following functions:

  - midx.c::find_commits_for_midx_bitmap()
  - midx.c::midx_pack_order()
  - midx.c::prepare_midx_packing_data()
  - midx.c::write_midx_bitmap()
  - midx.c::write_midx_internal()
  - midx.c::write_midx_reverse_index()

to start and end with a trace2_region_enter() and trace2_region_leave(),
respectively.

The category for all of these is "midx", which matches the existing
convention. The region description matches the name of the function.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/midx.c b/midx.c
index a8d2111e96169599462bd5490f2253dc7067dad6..4df701ee1131a9889b25473162f15879b72808b6 100644 (file)
--- a/midx.c
+++ b/midx.c
@@ -913,6 +913,8 @@ static uint32_t *midx_pack_order(struct write_midx_context *ctx)
        uint32_t *pack_order;
        uint32_t i;
 
+       trace2_region_enter("midx", "midx_pack_order", the_repository);
+
        ALLOC_ARRAY(data, ctx->entries_nr);
        for (i = 0; i < ctx->entries_nr; i++) {
                struct pack_midx_entry *e = &ctx->entries[i];
@@ -930,6 +932,8 @@ static uint32_t *midx_pack_order(struct write_midx_context *ctx)
                pack_order[i] = data[i].nr;
        free(data);
 
+       trace2_region_leave("midx", "midx_pack_order", the_repository);
+
        return pack_order;
 }
 
@@ -939,6 +943,8 @@ static void write_midx_reverse_index(char *midx_name, unsigned char *midx_hash,
        struct strbuf buf = STRBUF_INIT;
        const char *tmp_file;
 
+       trace2_region_enter("midx", "write_midx_reverse_index", the_repository);
+
        strbuf_addf(&buf, "%s-%s.rev", midx_name, hash_to_hex(midx_hash));
 
        tmp_file = write_rev_file_order(NULL, ctx->pack_order, ctx->entries_nr,
@@ -948,6 +954,8 @@ static void write_midx_reverse_index(char *midx_name, unsigned char *midx_hash,
                die(_("cannot store reverse index file"));
 
        strbuf_release(&buf);
+
+       trace2_region_leave("midx", "write_midx_reverse_index", the_repository);
 }
 
 static void clear_midx_files_ext(const char *object_dir, const char *ext,
@@ -963,6 +971,8 @@ static void prepare_midx_packing_data(struct packing_data *pdata,
 {
        uint32_t i;
 
+       trace2_region_enter("midx", "prepare_midx_packing_data", the_repository);
+
        memset(pdata, 0, sizeof(struct packing_data));
        prepare_packing_data(the_repository, pdata);
 
@@ -973,6 +983,8 @@ static void prepare_midx_packing_data(struct packing_data *pdata,
                oe_set_in_pack(pdata, to,
                               ctx->info[ctx->pack_perm[from->pack_int_id]].p);
        }
+
+       trace2_region_leave("midx", "prepare_midx_packing_data", the_repository);
 }
 
 static int add_ref_to_pending(const char *refname,
@@ -1070,6 +1082,9 @@ static struct commit **find_commits_for_midx_bitmap(uint32_t *indexed_commits_nr
        struct rev_info revs;
        struct bitmap_commit_cb cb = {0};
 
+       trace2_region_enter("midx", "find_commits_for_midx_bitmap",
+                           the_repository);
+
        cb.ctx = ctx;
 
        repo_init_revisions(the_repository, &revs, NULL);
@@ -1103,6 +1118,10 @@ static struct commit **find_commits_for_midx_bitmap(uint32_t *indexed_commits_nr
                *indexed_commits_nr_p = cb.commits_nr;
 
        release_revisions(&revs);
+
+       trace2_region_leave("midx", "find_commits_for_midx_bitmap",
+                           the_repository);
+
        return cb.commits;
 }
 
@@ -1120,6 +1139,8 @@ static int write_midx_bitmap(const char *midx_name,
        char *bitmap_name = xstrfmt("%s-%s.bitmap", midx_name,
                                        hash_to_hex(midx_hash));
 
+       trace2_region_enter("midx", "write_midx_bitmap", the_repository);
+
        if (flags & MIDX_WRITE_BITMAP_HASH_CACHE)
                options |= BITMAP_OPT_HASH_CACHE;
 
@@ -1165,6 +1186,9 @@ static int write_midx_bitmap(const char *midx_name,
 cleanup:
        free(index);
        free(bitmap_name);
+
+       trace2_region_leave("midx", "write_midx_bitmap", the_repository);
+
        return ret;
 }
 
@@ -1211,6 +1235,8 @@ static int write_midx_internal(const char *object_dir,
        int result = 0;
        struct chunkfile *cf;
 
+       trace2_region_enter("midx", "write_midx_internal", the_repository);
+
        get_midx_filename(&midx_name, object_dir);
        if (safe_create_leading_directories(midx_name.buf))
                die_errno(_("unable to create leading directories of %s"),
@@ -1552,6 +1578,8 @@ cleanup:
        free(ctx.pack_order);
        strbuf_release(&midx_name);
 
+       trace2_region_leave("midx", "write_midx_internal", the_repository);
+
        return result;
 }