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commit-graph: minimize commit_graph_data_slab access
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In an earlier patch, multiple struct acccesses to `graph_pos` and
`generation` were auto-converted to multiple method calls.

Since the values are fixed and commit-slab access costly, we would be
better off with storing the values as a local variable and reusing it.

Signed-off-by: Abhishek Kumar <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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@abhishekkumar2718 @gitster
abhishekkumar2718 authored and gitster committed Jun 17, 2020
1 parent c49c82a commit c752ad0
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Showing 5 changed files with 79 additions and 43 deletions.
5 changes: 3 additions & 2 deletions bloom.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,15 +33,16 @@ static int load_bloom_filter_from_graph(struct commit_graph *g,
struct commit *c)
{
uint32_t lex_pos, start_index, end_index;
uint32_t graph_pos = commit_graph_position(c);

while (commit_graph_position(c) < g->num_commits_in_base)
while (graph_pos < g->num_commits_in_base)
g = g->base_graph;

/* The commit graph commit 'c' lives in doesn't carry bloom filters. */
if (!g->chunk_bloom_indexes)
return 0;

lex_pos = commit_graph_position(c) - g->num_commits_in_base;
lex_pos = graph_pos - g->num_commits_in_base;

end_index = get_be32(g->chunk_bloom_indexes + 4 * lex_pos);

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40 changes: 26 additions & 14 deletions commit-graph.c
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Original file line number Diff line number Diff line change
Expand Up @@ -144,10 +144,12 @@ static int commit_gen_cmp(const void *va, const void *vb)
const struct commit *a = *(const struct commit **)va;
const struct commit *b = *(const struct commit **)vb;

uint32_t generation_a = commit_graph_generation(a);
uint32_t generation_b = commit_graph_generation(b);
/* lower generation commits first */
if (commit_graph_generation(a) < commit_graph_generation(b))
if (generation_a < generation_b)
return -1;
else if (commit_graph_generation(a) > commit_graph_generation(b))
else if (generation_a > generation_b)
return 1;

/* use date as a heuristic when generations are equal */
Expand Down Expand Up @@ -729,15 +731,18 @@ static struct commit_list **insert_parent_or_die(struct repository *r,
static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
{
const unsigned char *commit_data;
struct commit_graph_data *graph_data;
uint32_t lex_index;

while (pos < g->num_commits_in_base)
g = g->base_graph;

lex_index = pos - g->num_commits_in_base;
commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
commit_graph_data_at(item)->graph_pos = pos;
commit_graph_data_at(item)->generation = get_be32(commit_data + g->hash_len + 8) >> 2;

graph_data = commit_graph_data_at(item);
graph_data->graph_pos = pos;
graph_data->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
}

static inline void set_commit_tree(struct commit *c, struct tree *t)
Expand All @@ -753,6 +758,7 @@ static int fill_commit_in_graph(struct repository *r,
uint32_t *parent_data_ptr;
uint64_t date_low, date_high;
struct commit_list **pptr;
struct commit_graph_data *graph_data;
const unsigned char *commit_data;
uint32_t lex_index;

Expand All @@ -766,7 +772,8 @@ static int fill_commit_in_graph(struct repository *r,
* Store the "full" position, but then use the
* "local" position for the rest of the calculation.
*/
commit_graph_data_at(item)->graph_pos = pos;
graph_data = commit_graph_data_at(item);
graph_data->graph_pos = pos;
lex_index = pos - g->num_commits_in_base;

commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
Expand All @@ -779,7 +786,7 @@ static int fill_commit_in_graph(struct repository *r,
date_low = get_be32(commit_data + g->hash_len + 12);
item->date = (timestamp_t)((date_high << 32) | date_low);

commit_graph_data_at(item)->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
graph_data->generation = get_be32(commit_data + g->hash_len + 8) >> 2;

pptr = &item->parents;

Expand Down Expand Up @@ -811,8 +818,9 @@ static int fill_commit_in_graph(struct repository *r,

static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
{
if (commit_graph_position(item) != COMMIT_NOT_FROM_GRAPH) {
*pos = commit_graph_position(item);
uint32_t graph_pos = commit_graph_position(item);
if (graph_pos != COMMIT_NOT_FROM_GRAPH) {
*pos = graph_pos;
return 1;
} else {
struct commit_graph *cur_g = g;
Expand Down Expand Up @@ -867,12 +875,13 @@ static struct tree *load_tree_for_commit(struct repository *r,
{
struct object_id oid;
const unsigned char *commit_data;
uint32_t graph_pos = commit_graph_position(c);

while (commit_graph_position(c) < g->num_commits_in_base)
while (graph_pos < g->num_commits_in_base)
g = g->base_graph;

commit_data = g->chunk_commit_data +
GRAPH_DATA_WIDTH * (commit_graph_position(c) - g->num_commits_in_base);
GRAPH_DATA_WIDTH * (graph_pos - g->num_commits_in_base);

hashcpy(oid.hash, commit_data);
set_commit_tree(c, lookup_tree(r, &oid));
Expand Down Expand Up @@ -2299,6 +2308,7 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
struct commit *graph_commit, *odb_commit;
struct commit_list *graph_parents, *odb_parents;
uint32_t max_generation = 0;
uint32_t generation;

display_progress(progress, i + 1);
hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
Expand Down Expand Up @@ -2337,8 +2347,9 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
oid_to_hex(&graph_parents->item->object.oid),
oid_to_hex(&odb_parents->item->object.oid));

if (commit_graph_generation(graph_parents->item) > max_generation)
max_generation = commit_graph_generation(graph_parents->item);
generation = commit_graph_generation(graph_parents->item);
if (generation > max_generation)
max_generation = generation;

graph_parents = graph_parents->next;
odb_parents = odb_parents->next;
Expand Down Expand Up @@ -2368,10 +2379,11 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
if (max_generation == GENERATION_NUMBER_MAX)
max_generation--;

if (commit_graph_generation(graph_commit) != max_generation + 1)
generation = commit_graph_generation(graph_commit);
if (generation != max_generation + 1)
graph_report(_("commit-graph generation for commit %s is %u != %u"),
oid_to_hex(&cur_oid),
commit_graph_generation(graph_commit),
generation,
max_generation + 1);

if (graph_commit->date != odb_commit->date)
Expand Down
59 changes: 38 additions & 21 deletions commit-reach.c
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Original file line number Diff line number Diff line change
Expand Up @@ -58,14 +58,15 @@ static struct commit_list *paint_down_to_common(struct repository *r,
struct commit *commit = prio_queue_get(&queue);
struct commit_list *parents;
int flags;
uint32_t generation = commit_graph_generation(commit);

if (min_generation && commit_graph_generation(commit) > last_gen)
if (min_generation && generation > last_gen)
BUG("bad generation skip %8x > %8x at %s",
commit_graph_generation(commit), last_gen,
generation, last_gen,
oid_to_hex(&commit->object.oid));
last_gen = commit_graph_generation(commit);
last_gen = generation;

if (commit_graph_generation(commit) < min_generation)
if (generation < min_generation)
break;

flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
Expand Down Expand Up @@ -181,13 +182,15 @@ static int remove_redundant(struct repository *r, struct commit **array, int cnt
if (redundant[i])
continue;
for (j = filled = 0; j < cnt; j++) {
uint32_t curr_generation;
if (i == j || redundant[j])
continue;
filled_index[filled] = j;
work[filled++] = array[j];

if (commit_graph_generation(array[j]) < min_generation)
min_generation = commit_graph_generation(array[j]);
curr_generation = commit_graph_generation(array[j]);
if (curr_generation < min_generation)
min_generation = curr_generation;
}
common = paint_down_to_common(r, array[i], filled,
work, min_generation);
Expand Down Expand Up @@ -316,23 +319,26 @@ int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
{
struct commit_list *bases;
int ret = 0, i;
uint32_t min_generation = GENERATION_NUMBER_INFINITY;
uint32_t generation, min_generation = GENERATION_NUMBER_INFINITY;

if (repo_parse_commit(r, commit))
return ret;
for (i = 0; i < nr_reference; i++) {
if (repo_parse_commit(r, reference[i]))
return ret;
if (commit_graph_generation(reference[i]) < min_generation)
min_generation = commit_graph_generation(reference[i]);

generation = commit_graph_generation(reference[i]);
if (generation < min_generation)
min_generation = generation;
}

if (commit_graph_generation(commit) > min_generation)
generation = commit_graph_generation(commit);
if (generation > min_generation)
return ret;

bases = paint_down_to_common(r, commit,
nr_reference, reference,
commit_graph_generation(commit));
generation);
if (commit->object.flags & PARENT2)
ret = 1;
clear_commit_marks(commit, all_flags);
Expand Down Expand Up @@ -490,10 +496,12 @@ static enum contains_result contains_tag_algo(struct commit *candidate,
const struct commit_list *p;

for (p = want; p; p = p->next) {
uint32_t generation;
struct commit *c = p->item;
load_commit_graph_info(the_repository, c);
if (commit_graph_generation(c) < cutoff)
cutoff = commit_graph_generation(c);
generation = commit_graph_generation(c);
if (generation < cutoff)
cutoff = generation;
}

result = contains_test(candidate, want, cache, cutoff);
Expand Down Expand Up @@ -544,9 +552,12 @@ static int compare_commits_by_gen(const void *_a, const void *_b)
const struct commit *a = *(const struct commit * const *)_a;
const struct commit *b = *(const struct commit * const *)_b;

if (commit_graph_generation(a) < commit_graph_generation(b))
uint32_t generation_a = commit_graph_generation(a);
uint32_t generation_b = commit_graph_generation(b);

if (generation_a < generation_b)
return -1;
if (commit_graph_generation(a) > commit_graph_generation(b))
if (generation_a > generation_b)
return 1;
return 0;
}
Expand Down Expand Up @@ -662,23 +673,27 @@ int can_all_from_reach(struct commit_list *from, struct commit_list *to,
add_object_array(&from_iter->item->object, NULL, &from_objs);

if (!parse_commit(from_iter->item)) {
uint32_t generation;
if (from_iter->item->date < min_commit_date)
min_commit_date = from_iter->item->date;

if (commit_graph_generation(from_iter->item) < min_generation)
min_generation = commit_graph_generation(from_iter->item);
generation = commit_graph_generation(from_iter->item);
if (generation < min_generation)
min_generation = generation;
}

from_iter = from_iter->next;
}

while (to_iter) {
if (!parse_commit(to_iter->item)) {
uint32_t generation;
if (to_iter->item->date < min_commit_date)
min_commit_date = to_iter->item->date;

if (commit_graph_generation(to_iter->item) < min_generation)
min_generation = commit_graph_generation(to_iter->item);
generation = commit_graph_generation(to_iter->item);
if (generation < min_generation)
min_generation = generation;
}

to_iter->item->object.flags |= PARENT2;
Expand Down Expand Up @@ -718,11 +733,13 @@ struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
struct prio_queue queue = { compare_commits_by_gen_then_commit_date };

for (item = to; item < to_last; item++) {
uint32_t generation;
struct commit *c = *item;

parse_commit(c);
if (commit_graph_generation(c) < min_generation)
min_generation = commit_graph_generation(c);
generation = commit_graph_generation(c);
if (generation < min_generation)
min_generation = generation;

if (!(c->object.flags & PARENT1)) {
c->object.flags |= PARENT1;
Expand Down
6 changes: 4 additions & 2 deletions commit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -729,11 +729,13 @@ int compare_commits_by_author_date(const void *a_, const void *b_,
int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused)
{
const struct commit *a = a_, *b = b_;
const uint32_t generation_a = commit_graph_generation(a),
generation_b = commit_graph_generation(b);

/* newer commits first */
if (commit_graph_generation(a) < commit_graph_generation(b))
if (generation_a < generation_b)
return 1;
else if (commit_graph_generation(a) > commit_graph_generation(b))
else if (generation_a > generation_b)
return -1;

/* use date as a heuristic when generations are equal */
Expand Down
12 changes: 8 additions & 4 deletions revision.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3413,15 +3413,17 @@ static void init_topo_walk(struct rev_info *revs)
info->min_generation = GENERATION_NUMBER_INFINITY;
for (list = revs->commits; list; list = list->next) {
struct commit *c = list->item;
uint32_t generation;

if (parse_commit_gently(c, 1))
continue;

test_flag_and_insert(&info->explore_queue, c, TOPO_WALK_EXPLORED);
test_flag_and_insert(&info->indegree_queue, c, TOPO_WALK_INDEGREE);

if (commit_graph_generation(c) < info->min_generation)
info->min_generation = commit_graph_generation(c);
generation = commit_graph_generation(c);
if (generation < info->min_generation)
info->min_generation = generation;

*(indegree_slab_at(&info->indegree, c)) = 1;

Expand Down Expand Up @@ -3472,15 +3474,17 @@ static void expand_topo_walk(struct rev_info *revs, struct commit *commit)
for (p = commit->parents; p; p = p->next) {
struct commit *parent = p->item;
int *pi;
uint32_t generation;

if (parent->object.flags & UNINTERESTING)
continue;

if (parse_commit_gently(parent, 1) < 0)
continue;

if (commit_graph_generation(parent) < info->min_generation) {
info->min_generation = commit_graph_generation(parent);
generation = commit_graph_generation(parent);
if (generation < info->min_generation) {
info->min_generation = generation;
compute_indegrees_to_depth(revs, info->min_generation);
}

Expand Down

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