From 177722b344256b84f1c97b7363d3f19c04928039 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 10 Apr 2018 08:56:05 -0400 Subject: [PATCH 1/1] 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 Signed-off-by: Junio C Hamano --- alloc.c | 1 + commit-graph.c | 141 +++++++++++++++++++++++++++++++++++++++- commit-graph.h | 12 ++++ commit.c | 3 + commit.h | 3 + t/t5318-commit-graph.sh | 47 +++++++++++++- 6 files changed, 205 insertions(+), 2 deletions(-) diff --git a/alloc.c b/alloc.c index 12afadfacd..cf4f8b61e1 100644 --- a/alloc.c +++ b/alloc.c @@ -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; } diff --git a/commit-graph.c b/commit-graph.c index ea29c5c2d8..f745186e7f 100644 --- a/commit-graph.c +++ b/commit-graph.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 @@ cleanup_fail: 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); diff --git a/commit-graph.h b/commit-graph.h index 2528478f06..73b28beed1 100644 --- a/commit-graph.h +++ b/commit-graph.h @@ -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; diff --git a/commit.c b/commit.c index e8a49b9c84..eb61729d10 100644 --- a/commit.c +++ b/commit.c @@ -1,6 +1,7 @@ #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 : diff --git a/commit.h b/commit.h index 0fb8271665..e57ae4b583 100644 --- a/commit.h +++ b/commit.h @@ -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; diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh index 2f44f91193..51de9cc455 100755 --- a/t/t5318-commit-graph.sh +++ b/t/t5318-commit-graph.sh @@ -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 -- 2.47.1