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Merge branch 'nd/unpack-trees-with-cache-tree'

Browse Source 
The unpack_trees() API used in checking out a branch and merging
walks one or more trees along with the index.  When the cache-tree
in the index tells us that we are walking a tree whose flattened
contents is known (i.e. matches a span in the index), as linearly
scanning a span in the index is much more efficient than having to
open tree objects recursively and listing their entries, the walk
can be optimized, which is done in this topic.

* nd/unpack-trees-with-cache-tree:
  Document update for nd/unpack-trees-with-cache-tree
  cache-tree: verify valid cache-tree in the test suite
  unpack-trees: add missing cache invalidation
  unpack-trees: reuse (still valid) cache-tree from src_index
  unpack-trees: reduce malloc in cache-tree walk
  unpack-trees: optimize walking same trees with cache-tree
  unpack-trees: add performance tracing
  trace.h: support nested performance tracing
This commit is contained in:
Junio C Hamano 2018-09-17 13:53:53 -07:00
commit 7e794d0a3f
12 changed files with 344 additions and 22 deletions
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80
cache-tree.c
View File

@ -4,6 +4,7 @@
#include "tree-walk.h"
#include "cache-tree.h"
#include "object-store.h"
#include "replace-object.h"
#ifndef DEBUG
#define DEBUG 0
@ -433,7 +434,9 @@ int cache_tree_update(struct index_state *istate, int flags)
if (i)
return i;
trace_performance_enter();
i = update_one(it, cache, entries, "", 0, &skip, flags);
trace_performance_leave("cache_tree_update");
if (i < 0)
return i;
istate->cache_changed |= CACHE_TREE_CHANGED;
@ -718,3 +721,80 @@ int cache_tree_matches_traversal(struct cache_tree *root,
return it->entry_count;
return 0;
}
static void verify_one(struct index_state *istate,
struct cache_tree *it,
struct strbuf *path)
{
int i, pos, len = path->len;
struct strbuf tree_buf = STRBUF_INIT;
struct object_id new_oid;
for (i = 0; i < it->subtree_nr; i++) {
strbuf_addf(path, "%s/", it->down[i]->name);
verify_one(istate, it->down[i]->cache_tree, path);
strbuf_setlen(path, len);
}
if (it->entry_count < 0 ||
/* no verification on tests (t7003) that replace trees */
lookup_replace_object(the_repository, &it->oid) != &it->oid)
return;
if (path->len) {
pos = index_name_pos(istate, path->buf, path->len);
pos = -pos - 1;
} else {
pos = 0;
}
i = 0;
while (i < it->entry_count) {
struct cache_entry *ce = istate->cache[pos + i];
const char *slash;
struct cache_tree_sub *sub = NULL;
const struct object_id *oid;
const char *name;
unsigned mode;
int entlen;
if (ce->ce_flags & (CE_STAGEMASK | CE_INTENT_TO_ADD | CE_REMOVE))
BUG("%s with flags 0x%x should not be in cache-tree",
ce->name, ce->ce_flags);
name = ce->name + path->len;
slash = strchr(name, '/');
if (slash) {
entlen = slash - name;
sub = find_subtree(it, ce->name + path->len, entlen, 0);
if (!sub || sub->cache_tree->entry_count < 0)
BUG("bad subtree '%.*s'", entlen, name);
oid = &sub->cache_tree->oid;
mode = S_IFDIR;
i += sub->cache_tree->entry_count;
} else {
oid = &ce->oid;
mode = ce->ce_mode;
entlen = ce_namelen(ce) - path->len;
i++;
}
strbuf_addf(&tree_buf, "%o %.*s%c", mode, entlen, name, '\0');
strbuf_add(&tree_buf, oid->hash, the_hash_algo->rawsz);
}
hash_object_file(tree_buf.buf, tree_buf.len, tree_type, &new_oid);
if (oidcmp(&new_oid, &it->oid))
BUG("cache-tree for path %.*s does not match. "
"Expected %s got %s", len, path->buf,
oid_to_hex(&new_oid), oid_to_hex(&it->oid));
strbuf_setlen(path, len);
strbuf_release(&tree_buf);
}
void cache_tree_verify(struct index_state *istate)
{
struct strbuf path = STRBUF_INIT;
if (!istate->cache_tree)
return;
verify_one(istate, istate->cache_tree, &path);
strbuf_release(&path);
}

1
cache-tree.h
View File

@ -32,6 +32,7 @@ struct cache_tree *cache_tree_read(const char *buffer, unsigned long size);
int cache_tree_fully_valid(struct cache_tree *);
int cache_tree_update(struct index_state *, int);
void cache_tree_verify(struct index_state *);
/* bitmasks to write_cache_as_tree flags */
#define WRITE_TREE_MISSING_OK 1

4
diff-lib.c
View File

@ -518,11 +518,11 @@ static int diff_cache(struct rev_info *revs,
int run_diff_index(struct rev_info *revs, int cached)
{
struct object_array_entry *ent;
uint64_t start = getnanotime();
if (revs->pending.nr != 1)
BUG("run_diff_index must be passed exactly one tree");
trace_performance_enter();
ent = revs->pending.objects;
if (diff_cache(revs, &ent->item->oid, ent->name, cached))
exit(128);
@ -531,7 +531,7 @@ int run_diff_index(struct rev_info *revs, int cached)
diffcore_fix_diff_index(&revs->diffopt);
diffcore_std(&revs->diffopt);
diff_flush(&revs->diffopt);
trace_performance_since(start, "diff-index");
trace_performance_leave("diff-index");
return 0;
}

9
dir.c
View File

@ -2268,10 +2268,13 @@ int read_directory(struct dir_struct *dir, struct index_state *istate,
const char *path, int len, const struct pathspec *pathspec)
{
struct untracked_cache_dir *untracked;
uint64_t start = getnanotime();
if (has_symlink_leading_path(path, len))
trace_performance_enter();
if (has_symlink_leading_path(path, len)) {
trace_performance_leave("read directory %.*s", len, path);
return dir->nr;
}
untracked = validate_untracked_cache(dir, len, pathspec);
if (!untracked)
@ -2307,7 +2310,7 @@ int read_directory(struct dir_struct *dir, struct index_state *istate,
dir->nr = i;
}
trace_performance_since(start, "read directory %.*s", len, path);
trace_performance_leave("read directory %.*s", len, path);
if (dir->untracked) {
static int force_untracked_cache = -1;
static struct trace_key trace_untracked_stats = TRACE_KEY_INIT(UNTRACKED_STATS);

4
name-hash.c
View File

@ -578,10 +578,10 @@ static void threaded_lazy_init_name_hash(
static void lazy_init_name_hash(struct index_state *istate)
{
uint64_t start = getnanotime();
if (istate->name_hash_initialized)
return;
trace_performance_enter();
hashmap_init(&istate->name_hash, cache_entry_cmp, NULL, istate->cache_nr);
hashmap_init(&istate->dir_hash, dir_entry_cmp, NULL, istate->cache_nr);
@ -602,7 +602,7 @@ static void lazy_init_name_hash(struct index_state *istate)
}
istate->name_hash_initialized = 1;
trace_performance_since(start, "initialize name hash");
trace_performance_leave("initialize name hash");
}
/*

4
preload-index.c
View File

@ -78,7 +78,6 @@ static void preload_index(struct index_state *index,
{
int threads, i, work, offset;
struct thread_data data[MAX_PARALLEL];
uint64_t start = getnanotime();
if (!core_preload_index)
return;
@ -88,6 +87,7 @@ static void preload_index(struct index_state *index,
threads = 2;
if (threads < 2)
return;
trace_performance_enter();
if (threads > MAX_PARALLEL)
threads = MAX_PARALLEL;
offset = 0;
@ -109,7 +109,7 @@ static void preload_index(struct index_state *index,
if (pthread_join(p->pthread, NULL))
die("unable to join threaded lstat");
}
trace_performance_since(start, "preload index");
trace_performance_leave("preload index");
}
#endif

16
read-cache.c
View File

@ -1476,8 +1476,8 @@ int refresh_index(struct index_state *istate, unsigned int flags,
const char *typechange_fmt;
const char *added_fmt;
const char *unmerged_fmt;
uint64_t start = getnanotime();
trace_performance_enter();
modified_fmt = (in_porcelain ? "M\t%s\n" : "%s: needs update\n");
deleted_fmt = (in_porcelain ? "D\t%s\n" : "%s: needs update\n");
typechange_fmt = (in_porcelain ? "T\t%s\n" : "%s needs update\n");
@ -1547,7 +1547,7 @@ int refresh_index(struct index_state *istate, unsigned int flags,
replace_index_entry(istate, i, new_entry);
}
trace_performance_since(start, "refresh index");
trace_performance_leave("refresh index");
return has_errors;
}
@ -2002,7 +2002,6 @@ static void freshen_shared_index(const char *shared_index, int warn)
int read_index_from(struct index_state *istate, const char *path,
const char *gitdir)
{
uint64_t start = getnanotime();
struct split_index *split_index;
int ret;
char *base_oid_hex;
@ -2012,8 +2011,9 @@ int read_index_from(struct index_state *istate, const char *path,
if (istate->initialized)
return istate->cache_nr;
trace_performance_enter();
ret = do_read_index(istate, path, 0);
trace_performance_since(start, "read cache %s", path);
trace_performance_leave("read cache %s", path);
split_index = istate->split_index;
if (!split_index || is_null_oid(&split_index->base_oid)) {
@ -2021,6 +2021,7 @@ int read_index_from(struct index_state *istate, const char *path,
return ret;
}
trace_performance_enter();
if (split_index->base)
discard_index(split_index->base);
else
@ -2037,8 +2038,8 @@ int read_index_from(struct index_state *istate, const char *path,
freshen_shared_index(base_path, 0);
merge_base_index(istate);
post_read_index_from(istate);
trace_performance_since(start, "read cache %s", base_path);
free(base_path);
trace_performance_leave("read cache %s", base_path);
return ret;
}
@ -2743,6 +2744,9 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
int new_shared_index, ret;
struct split_index *si = istate->split_index;
if (git_env_bool("GIT_TEST_CHECK_CACHE_TREE", 0))
cache_tree_verify(istate);
if ((flags & SKIP_IF_UNCHANGED) && !istate->cache_changed) {
if (flags & COMMIT_LOCK)
rollback_lock_file(lock);
@ -2939,6 +2943,8 @@ void move_index_extensions(struct index_state *dst, struct index_state *src)
{
dst->untracked = src->untracked;
src->untracked = NULL;
dst->cache_tree = src->cache_tree;
src->cache_tree = NULL;
}
struct cache_entry *dup_cache_entry(const struct cache_entry *ce,

4
t/README
View File

@ -319,6 +319,10 @@ GIT_TEST_OE_DELTA_SIZE=<n> exercises the uncomon pack-objects code
path where deltas larger than this limit require extra memory
allocation for bookkeeping.
GIT_TEST_VALIDATE_INDEX_CACHE_ENTRIES=<boolean> checks that cache-tree
records are valid when the index is written out or after a merge. This
is mostly to catch missing invalidation. Default is true.
Naming Tests
------------

6
t/test-lib.sh
View File

@ -1083,6 +1083,12 @@ else
test_set_prereq C_LOCALE_OUTPUT
fi
if test -z "$GIT_TEST_CHECK_CACHE_TREE"
then
GIT_TEST_CHECK_CACHE_TREE=true
export GIT_TEST_CHECK_CACHE_TREE
fi
test_lazy_prereq PIPE '
# test whether the filesystem supports FIFOs
test_have_prereq !MINGW,!CYGWIN &&

69
trace.c
View File

@ -176,10 +176,30 @@ void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
strbuf_release(&buf);
}
static uint64_t perf_start_times[10];
static int perf_indent;
uint64_t trace_performance_enter(void)
{
uint64_t now;
if (!trace_want(&trace_perf_key))
return 0;
now = getnanotime();
perf_start_times[perf_indent] = now;
if (perf_indent + 1 < ARRAY_SIZE(perf_start_times))
perf_indent++;
else
BUG("Too deep indentation");
return now;
}
static void trace_performance_vprintf_fl(const char *file, int line,
uint64_t nanos, const char *format,
va_list ap)
{
static const char space[] = " ";
struct strbuf buf = STRBUF_INIT;
if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
@ -188,7 +208,10 @@ static void trace_performance_vprintf_fl(const char *file, int line,
strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
if (format && *format) {
strbuf_addstr(&buf, ": ");
if (perf_indent >= strlen(space))
BUG("Too deep indentation");
strbuf_addf(&buf, ":%.*s ", perf_indent, space);
strbuf_vaddf(&buf, format, ap);
}
@ -244,6 +267,24 @@ void trace_performance_since(uint64_t start, const char *format, ...)
va_end(ap);
}
void trace_performance_leave(const char *format, ...)
{
va_list ap;
uint64_t since;
if (perf_indent)
perf_indent--;
if (!format) /* Allow callers to leave without tracing anything */
return;
since = perf_start_times[perf_indent];
va_start(ap, format);
trace_performance_vprintf_fl(NULL, 0, getnanotime() - since,
format, ap);
va_end(ap);
}
#else
void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
@ -273,6 +314,24 @@ void trace_performance_fl(const char *file, int line, uint64_t nanos,
va_end(ap);
}
void trace_performance_leave_fl(const char *file, int line,
uint64_t nanos, const char *format, ...)
{
va_list ap;
uint64_t since;
if (perf_indent)
perf_indent--;
if (!format) /* Allow callers to leave without tracing anything */
return;
since = perf_start_times[perf_indent];
va_start(ap, format);
trace_performance_vprintf_fl(file, line, nanos - since, format, ap);
va_end(ap);
}
#endif /* HAVE_VARIADIC_MACROS */
@ -411,13 +470,11 @@ uint64_t getnanotime(void)
}
}
static uint64_t command_start_time;
static struct strbuf command_line = STRBUF_INIT;
static void print_command_performance_atexit(void)
{
trace_performance_since(command_start_time, "git command:%s",
command_line.buf);
trace_performance_leave("git command:%s", command_line.buf);
}
void trace_command_performance(const char **argv)
@ -425,10 +482,10 @@ void trace_command_performance(const char **argv)
if (!trace_want(&trace_perf_key))
return;
if (!command_start_time)
if (!command_line.len)
atexit(print_command_performance_atexit);
strbuf_reset(&command_line);
sq_quote_argv_pretty(&command_line, argv);
command_start_time = getnanotime();
trace_performance_enter();
}

15
trace.h
View File

@ -23,6 +23,7 @@ extern void trace_disable(struct trace_key *key);
extern uint64_t getnanotime(void);
extern void trace_command_performance(const char **argv);
extern void trace_verbatim(struct trace_key *key, const void *buf, unsigned len);
uint64_t trace_performance_enter(void);
#ifndef HAVE_VARIADIC_MACROS
@ -45,6 +46,9 @@ extern void trace_performance(uint64_t nanos, const char *format, ...);
__attribute__((format (printf, 2, 3)))
extern void trace_performance_since(uint64_t start, const char *format, ...);
__attribute__((format (printf, 1, 2)))
void trace_performance_leave(const char *format, ...);
#else
/*
@ -118,6 +122,14 @@ extern void trace_performance_since(uint64_t start, const char *format, ...);
__VA_ARGS__); \
} while (0)
#define trace_performance_leave(...) \
do { \
if (trace_pass_fl(&trace_perf_key)) \
trace_performance_leave_fl(TRACE_CONTEXT, __LINE__, \
getnanotime(), \
__VA_ARGS__); \
} while (0)
/* backend functions, use non-*fl macros instead */
__attribute__((format (printf, 4, 5)))
extern void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
@ -130,6 +142,9 @@ extern void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
__attribute__((format (printf, 4, 5)))
extern void trace_performance_fl(const char *file, int line,
uint64_t nanos, const char *fmt, ...);
__attribute__((format (printf, 4, 5)))
extern void trace_performance_leave_fl(const char *file, int line,
uint64_t nanos, const char *fmt, ...);
static inline int trace_pass_fl(struct trace_key *key)
{
return key->fd || !key->initialized;

154
unpack-trees.c
View File

@ -385,6 +385,7 @@ static int check_updates(struct unpack_trees_options *o)
struct checkout state = CHECKOUT_INIT;
int i;
trace_performance_enter();
state.force = 1;
state.quiet = 1;
state.refresh_cache = 1;
@ -461,6 +462,7 @@ static int check_updates(struct unpack_trees_options *o)
if (o->clone)
report_collided_checkout(index);
trace_performance_leave("check_updates");
return errs != 0;
}
@ -680,6 +682,113 @@ static inline int are_same_oid(struct name_entry *name_j, struct name_entry *nam
return name_j->oid && name_k->oid && !oidcmp(name_j->oid, name_k->oid);
}
static int all_trees_same_as_cache_tree(int n, unsigned long dirmask,
struct name_entry *names,
struct traverse_info *info)
{
struct unpack_trees_options *o = info->data;
int i;
if (!o->merge || dirmask != ((1 << n) - 1))
return 0;
for (i = 1; i < n; i++)
if (!are_same_oid(names, names + i))
return 0;
return cache_tree_matches_traversal(o->src_index->cache_tree, names, info);
}
static int index_pos_by_traverse_info(struct name_entry *names,
struct traverse_info *info)
{
struct unpack_trees_options *o = info->data;
int len = traverse_path_len(info, names);
char *name = xmalloc(len + 1 /* slash */ + 1 /* NUL */);
int pos;
make_traverse_path(name, info, names);
name[len++] = '/';
name[len] = '\0';
pos = index_name_pos(o->src_index, name, len);
if (pos >= 0)
BUG("This is a directory and should not exist in index");
pos = -pos - 1;
if (!starts_with(o->src_index->cache[pos]->name, name) ||
(pos > 0 && starts_with(o->src_index->cache[pos-1]->name, name)))
BUG("pos must point at the first entry in this directory");
free(name);
return pos;
}
/*
* Fast path if we detect that all trees are the same as cache-tree at this
* path. We'll walk these trees in an iterative loop using cache-tree/index
* instead of ODB since we already know what these trees contain.
*/
static int traverse_by_cache_tree(int pos, int nr_entries, int nr_names,
struct name_entry *names,
struct traverse_info *info)
{
struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
struct unpack_trees_options *o = info->data;
struct cache_entry *tree_ce = NULL;
int ce_len = 0;
int i, d;
if (!o->merge)
BUG("We need cache-tree to do this optimization");
/*
* Do what unpack_callback() and unpack_nondirectories() normally
* do. But we walk all paths in an iterative loop instead.
*
* D/F conflicts and higher stage entries are not a concern
* because cache-tree would be invalidated and we would never
* get here in the first place.
*/
for (i = 0; i < nr_entries; i++) {
int new_ce_len, len, rc;
src[0] = o->src_index->cache[pos + i];
len = ce_namelen(src[0]);
new_ce_len = cache_entry_size(len);
if (new_ce_len > ce_len) {
new_ce_len <<= 1;
tree_ce = xrealloc(tree_ce, new_ce_len);
memset(tree_ce, 0, new_ce_len);
ce_len = new_ce_len;
tree_ce->ce_flags = create_ce_flags(0);
for (d = 1; d <= nr_names; d++)
src[d] = tree_ce;
}
tree_ce->ce_mode = src[0]->ce_mode;
tree_ce->ce_namelen = len;
oidcpy(&tree_ce->oid, &src[0]->oid);
memcpy(tree_ce->name, src[0]->name, len + 1);
rc = call_unpack_fn((const struct cache_entry * const *)src, o);
if (rc < 0) {
free(tree_ce);
return rc;
}
mark_ce_used(src[0], o);
}
free(tree_ce);
if (o->debug_unpack)
printf("Unpacked %d entries from %s to %s using cache-tree\n",
nr_entries,
o->src_index->cache[pos]->name,
o->src_index->cache[pos + nr_entries - 1]->name);
return 0;
}
static int traverse_trees_recursive(int n, unsigned long dirmask,
unsigned long df_conflicts,
struct name_entry *names,
@ -691,6 +800,27 @@ static int traverse_trees_recursive(int n, unsigned long dirmask,
void *buf[MAX_UNPACK_TREES];
struct traverse_info newinfo;
struct name_entry *p;
int nr_entries;
nr_entries = all_trees_same_as_cache_tree(n, dirmask, names, info);
if (nr_entries > 0) {
struct unpack_trees_options *o = info->data;
int pos = index_pos_by_traverse_info(names, info);
if (!o->merge || df_conflicts)
BUG("Wrong condition to get here buddy");
/*
* All entries up to 'pos' must have been processed
* (i.e. marked CE_UNPACKED) at this point. But to be safe,
* save and restore cache_bottom anyway to not miss
* unprocessed entries before 'pos'.
*/
bottom = o->cache_bottom;
ret = traverse_by_cache_tree(pos, nr_entries, n, names, info);
o->cache_bottom = bottom;
return ret;
}
p = names;
while (!p->mode)
@ -857,6 +987,11 @@ static struct cache_entry *create_ce_entry(const struct traverse_info *info,
return ce;
}
/*
* Note that traverse_by_cache_tree() duplicates some logic in this function
* without actually calling it. If you change the logic here you may need to
* check and change there as well.
*/
static int unpack_nondirectories(int n, unsigned long mask,
unsigned long dirmask,
struct cache_entry **src,
@ -1049,6 +1184,11 @@ static void debug_unpack_callback(int n,
debug_name_entry(i, names + i);
}
/*
* Note that traverse_by_cache_tree() duplicates some logic in this function
* without actually calling it. If you change the logic here you may need to
* check and change there as well.
*/
static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
{
struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
@ -1336,6 +1476,7 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
if (len > MAX_UNPACK_TREES)
die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
trace_performance_enter();
memset(&el, 0, sizeof(el));
if (!core_apply_sparse_checkout || !o->update)
o->skip_sparse_checkout = 1;
@ -1408,7 +1549,10 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
}
}
if (traverse_trees(len, t, &info) < 0)
trace_performance_enter();
ret = traverse_trees(len, t, &info);
trace_performance_leave("traverse_trees");
if (ret < 0)
goto return_failed;
}
@ -1483,7 +1627,10 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
ret = check_updates(o) ? (-2) : 0;
if (o->dst_index) {
move_index_extensions(&o->result, o->src_index);
if (!ret) {
if (git_env_bool("GIT_TEST_CHECK_CACHE_TREE", 0))
cache_tree_verify(&o->result);
if (!o->result.cache_tree)
o->result.cache_tree = cache_tree();
if (!cache_tree_fully_valid(o->result.cache_tree))
@ -1491,7 +1638,6 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
WRITE_TREE_SILENT |
WRITE_TREE_REPAIR);
}
move_index_extensions(&o->result, o->src_index);
discard_index(o->dst_index);
*o->dst_index = o->result;
} else {
@ -1500,6 +1646,7 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
o->src_index = NULL;
done:
trace_performance_leave("unpack_trees");
clear_exclude_list(&el);
return ret;
@ -1691,6 +1838,7 @@ static int verify_clean_subdirectory(const struct cache_entry *ce,
if (verify_uptodate(ce2, o))
return -1;
add_entry(o, ce2, CE_REMOVE, 0);
invalidate_ce_path(ce, o);
mark_ce_used(ce2, o);
}
cnt++;
@ -1950,6 +2098,8 @@ static int keep_entry(const struct cache_entry *ce,
struct unpack_trees_options *o)
{
add_entry(o, ce, 0, 0);
if (ce_stage(ce))
invalidate_ce_path(ce, o);
return 1;
}