Commit 177722b3 authored by Derrick Stolee's avatar Derrick Stolee Committed by Junio C Hamano

commit: integrate commit graph with commit parsing

Teach Git to inspect a commit graph file to supply the contents of a
struct commit when calling parse_commit_gently(). This implementation
satisfies all post-conditions on the struct commit, including loading
parents, the root tree, and the commit date.

If core.commitGraph is false, then do not check graph files.

In test script t5318-commit-graph.sh, add output-matching conditions on
read-only graph operations.

By loading commits from the graph instead of parsing commit buffers, we
save a lot of time on long commit walks. Here are some performance
results for a copy of the Linux repository where 'master' has 678,653
reachable commits and is behind 'origin/master' by 59,929 commits.

| Command                          | Before | After  | Rel % |
|----------------------------------|--------|--------|-------|
| log --oneline --topo-order -1000 |  8.31s |  0.94s | -88%  |
| branch -vv                       |  1.02s |  0.14s | -86%  |
| rev-list --all                   |  5.89s |  1.07s | -81%  |
| rev-list --all --objects         | 66.15s | 58.45s | -11%  |
Signed-off-by: Derrick Stolee's avatarDerrick Stolee <dstolee@microsoft.com>
Signed-off-by: default avatarJunio C Hamano <gitster@pobox.com>
parent 4f2542b4
......@@ -93,6 +93,7 @@ void *alloc_commit_node(void)
struct commit *c = alloc_node(&commit_state, sizeof(struct commit));
c->object.type = OBJ_COMMIT;
c->index = alloc_commit_index();
c->graph_pos = COMMIT_NOT_FROM_GRAPH;
return c;
}
......
......@@ -38,7 +38,6 @@
#define GRAPH_MIN_SIZE (5 * GRAPH_CHUNKLOOKUP_WIDTH + GRAPH_FANOUT_SIZE + \
GRAPH_OID_LEN + 8)
char *get_commit_graph_filename(const char *obj_dir)
{
return xstrfmt("%s/info/commit-graph", obj_dir);
......@@ -179,6 +178,145 @@ struct commit_graph *load_commit_graph_one(const char *graph_file)
exit(1);
}
/* global storage */
static struct commit_graph *commit_graph = NULL;
static void prepare_commit_graph_one(const char *obj_dir)
{
char *graph_name;
if (commit_graph)
return;
graph_name = get_commit_graph_filename(obj_dir);
commit_graph = load_commit_graph_one(graph_name);
FREE_AND_NULL(graph_name);
}
static int prepare_commit_graph_run_once = 0;
static void prepare_commit_graph(void)
{
struct alternate_object_database *alt;
char *obj_dir;
if (prepare_commit_graph_run_once)
return;
prepare_commit_graph_run_once = 1;
obj_dir = get_object_directory();
prepare_commit_graph_one(obj_dir);
prepare_alt_odb();
for (alt = alt_odb_list; !commit_graph && alt; alt = alt->next)
prepare_commit_graph_one(alt->path);
}
static void close_commit_graph(void)
{
if (!commit_graph)
return;
if (commit_graph->graph_fd >= 0) {
munmap((void *)commit_graph->data, commit_graph->data_len);
commit_graph->data = NULL;
close(commit_graph->graph_fd);
}
FREE_AND_NULL(commit_graph);
}
static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
{
return bsearch_hash(oid->hash, g->chunk_oid_fanout,
g->chunk_oid_lookup, g->hash_len, pos);
}
static struct commit_list **insert_parent_or_die(struct commit_graph *g,
uint64_t pos,
struct commit_list **pptr)
{
struct commit *c;
struct object_id oid;
hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * pos);
c = lookup_commit(&oid);
if (!c)
die("could not find commit %s", oid_to_hex(&oid));
c->graph_pos = pos;
return &commit_list_insert(c, pptr)->next;
}
static int fill_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t pos)
{
struct object_id oid;
uint32_t edge_value;
uint32_t *parent_data_ptr;
uint64_t date_low, date_high;
struct commit_list **pptr;
const unsigned char *commit_data = g->chunk_commit_data + (g->hash_len + 16) * pos;
item->object.parsed = 1;
item->graph_pos = pos;
hashcpy(oid.hash, commit_data);
item->tree = lookup_tree(&oid);
date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
date_low = get_be32(commit_data + g->hash_len + 12);
item->date = (timestamp_t)((date_high << 32) | date_low);
pptr = &item->parents;
edge_value = get_be32(commit_data + g->hash_len);
if (edge_value == GRAPH_PARENT_NONE)
return 1;
pptr = insert_parent_or_die(g, edge_value, pptr);
edge_value = get_be32(commit_data + g->hash_len + 4);
if (edge_value == GRAPH_PARENT_NONE)
return 1;
if (!(edge_value & GRAPH_OCTOPUS_EDGES_NEEDED)) {
pptr = insert_parent_or_die(g, edge_value, pptr);
return 1;
}
parent_data_ptr = (uint32_t*)(g->chunk_large_edges +
4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
do {
edge_value = get_be32(parent_data_ptr);
pptr = insert_parent_or_die(g,
edge_value & GRAPH_EDGE_LAST_MASK,
pptr);
parent_data_ptr++;
} while (!(edge_value & GRAPH_LAST_EDGE));
return 1;
}
int parse_commit_in_graph(struct commit *item)
{
if (!core_commit_graph)
return 0;
if (item->object.parsed)
return 1;
prepare_commit_graph();
if (commit_graph) {
uint32_t pos;
int found;
if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
pos = item->graph_pos;
found = 1;
} else {
found = bsearch_graph(commit_graph, &(item->object.oid), &pos);
}
if (found)
return fill_commit_in_graph(item, commit_graph, pos);
}
return 0;
}
static void write_graph_chunk_fanout(struct hashfile *f,
struct commit **commits,
int nr_commits)
......@@ -530,6 +668,7 @@ void write_commit_graph(const char *obj_dir)
write_graph_chunk_data(f, GRAPH_OID_LEN, commits.list, commits.nr);
write_graph_chunk_large_edges(f, commits.list, commits.nr);
close_commit_graph();
finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
commit_lock_file(&lk);
......
......@@ -5,6 +5,18 @@
char *get_commit_graph_filename(const char *obj_dir);
/*
* Given a commit struct, try to fill the commit struct info, including:
* 1. tree object
* 2. date
* 3. parents.
*
* Returns 1 if and only if the commit was found in the packed graph.
*
* See parse_commit_buffer() for the fallback after this call.
*/
int parse_commit_in_graph(struct commit *item);
struct commit_graph {
int graph_fd;
......
#include "cache.h"
#include "tag.h"
#include "commit.h"
#include "commit-graph.h"
#include "pkt-line.h"
#include "utf8.h"
#include "diff.h"
......@@ -383,6 +384,8 @@ int parse_commit_gently(struct commit *item, int quiet_on_missing)
return -1;
if (item->object.parsed)
return 0;
if (parse_commit_in_graph(item))
return 0;
buffer = read_sha1_file(item->object.oid.hash, &type, &size);
if (!buffer)
return quiet_on_missing ? -1 :
......
......@@ -9,6 +9,8 @@
#include "string-list.h"
#include "pretty.h"
#define COMMIT_NOT_FROM_GRAPH 0xFFFFFFFF
struct commit_list {
struct commit *item;
struct commit_list *next;
......@@ -21,6 +23,7 @@ struct commit {
timestamp_t date;
struct commit_list *parents;
struct tree *tree;
uint32_t graph_pos;
};
extern int save_commit_buffer;
......
......@@ -7,6 +7,7 @@ test_expect_success 'setup full repo' '
mkdir full &&
cd "$TRASH_DIRECTORY/full" &&
git init &&
git config core.commitGraph true &&
objdir=".git/objects"
'
......@@ -26,6 +27,29 @@ test_expect_success 'create commits and repack' '
git repack
'
graph_git_two_modes() {
git -c core.graph=true $1 >output
git -c core.graph=false $1 >expect
test_cmp output expect
}
graph_git_behavior() {
MSG=$1
DIR=$2
BRANCH=$3
COMPARE=$4
test_expect_success "check normal git operations: $MSG" '
cd "$TRASH_DIRECTORY/$DIR" &&
graph_git_two_modes "log --oneline $BRANCH" &&
graph_git_two_modes "log --topo-order $BRANCH" &&
graph_git_two_modes "log --graph $COMPARE..$BRANCH" &&
graph_git_two_modes "branch -vv" &&
graph_git_two_modes "merge-base -a $BRANCH $COMPARE"
'
}
graph_git_behavior 'no graph' full commits/3 commits/1
graph_read_expect() {
OPTIONAL=""
NUM_CHUNKS=3
......@@ -50,6 +74,8 @@ test_expect_success 'write graph' '
graph_read_expect "3"
'
graph_git_behavior 'graph exists' full commits/3 commits/1
test_expect_success 'Add more commits' '
cd "$TRASH_DIRECTORY/full" &&
git reset --hard commits/1 &&
......@@ -86,7 +112,6 @@ test_expect_success 'Add more commits' '
# |___/____/
# 1
test_expect_success 'write graph with merges' '
cd "$TRASH_DIRECTORY/full" &&
git commit-graph write &&
......@@ -94,6 +119,10 @@ test_expect_success 'write graph with merges' '
graph_read_expect "10" "large_edges"
'
graph_git_behavior 'merge 1 vs 2' full merge/1 merge/2
graph_git_behavior 'merge 1 vs 3' full merge/1 merge/3
graph_git_behavior 'merge 2 vs 3' full merge/2 merge/3
test_expect_success 'Add one more commit' '
cd "$TRASH_DIRECTORY/full" &&
test_commit 8 &&
......@@ -115,6 +144,9 @@ test_expect_success 'Add one more commit' '
# |___/____/
# 1
graph_git_behavior 'mixed mode, commit 8 vs merge 1' full commits/8 merge/1
graph_git_behavior 'mixed mode, commit 8 vs merge 2' full commits/8 merge/2
test_expect_success 'write graph with new commit' '
cd "$TRASH_DIRECTORY/full" &&
git commit-graph write &&
......@@ -122,6 +154,9 @@ test_expect_success 'write graph with new commit' '
graph_read_expect "11" "large_edges"
'
graph_git_behavior 'full graph, commit 8 vs merge 1' full commits/8 merge/1
graph_git_behavior 'full graph, commit 8 vs merge 2' full commits/8 merge/2
test_expect_success 'write graph with nothing new' '
cd "$TRASH_DIRECTORY/full" &&
git commit-graph write &&
......@@ -129,13 +164,20 @@ test_expect_success 'write graph with nothing new' '
graph_read_expect "11" "large_edges"
'
graph_git_behavior 'cleared graph, commit 8 vs merge 1' full commits/8 merge/1
graph_git_behavior 'cleared graph, commit 8 vs merge 2' full commits/8 merge/2
test_expect_success 'setup bare repo' '
cd "$TRASH_DIRECTORY" &&
git clone --bare --no-local full bare &&
cd bare &&
git config core.commitGraph true &&
baredir="./objects"
'
graph_git_behavior 'bare repo, commit 8 vs merge 1' bare commits/8 merge/1
graph_git_behavior 'bare repo, commit 8 vs merge 2' bare commits/8 merge/2
test_expect_success 'write graph in bare repo' '
cd "$TRASH_DIRECTORY/bare" &&
git commit-graph write &&
......@@ -143,4 +185,7 @@ test_expect_success 'write graph in bare repo' '
graph_read_expect "11" "large_edges"
'
graph_git_behavior 'bare repo with graph, commit 8 vs merge 1' bare commits/8 merge/1
graph_git_behavior 'bare repo with graph, commit 8 vs merge 2' bare commits/8 merge/2
test_done
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