Re: [PATCH v4 0/5] Speed up unpack_trees()
- From
Ben Peart <peartben@gmail.com>
- Date
- Aug 14, 2018, 19:19 UTC
- Message-ID
- <a0d4142a-795d-ddd3-0c9b-b54131591b7c@gmail.com>
- In-Reply-To
- <20180812081551.27927-1-pclouds@gmail.com>
On 8/12/2018 4:15 AM, Nguyễn Thái Ngọc Duy wrote:
Show 19 quoted lines
> v4 has a bunch of changes > > - 1/5 is a new one to show indented tracing. This way it's less > misleading to read nested time measurements > - 3/5 now has the switch/restore cache_bottom logic. Junio suggested a > check instead in his final note, but I think this is safer (yeah I'm > scared too) > - the old 4/4 is dropped because > - it assumes n-way logic > - the visible time saving is not worth the tradeoff > - Elijah gave me an idea to avoid add_index_entry() that I think > does not have n-way logic assumptions and gives better saving. > But it requires some more changes so I'm going to do it later > - 5/5 is also new and should help reduce cache_tree_update() cost. > I wrote somewhere I was not going to work on this part, but it turns > out just a couple lines, might as well do it now. > > Interdiff >
I've now had a chance to run the git tests, as well as our own unit and functional tests with this patch series and all passed.
I reviewed the tests in t0090-cache-tree.h and verified that there are tests that validate the cache tree is correct after doing a checkout and merge (both of which exercise the new cache tree optimization in patch 5).
I've also run our perf test suite and the results are outstanding:
Checkout saves 51% on average Merge saves 44% Pull saves 30% Rebase saves 26%
For perspective, that means these commands are going from ~20 seconds to ~10 seconds.
I don't feel that any of my comments to the individual patches deserve a re-roll. Given the ongoing discussion about the additional tracing - I'm happy to leave out the first 2 patches so that the rest can go in sooner rather than later.
Looks good!
Show 584 quoted lines
> diff --git a/cache-tree.c b/cache-tree.c
> index 0dbe10fc85..105f13806f 100644
> --- a/cache-tree.c
> +++ b/cache-tree.c
> @@ -426,7 +426,6 @@ static int update_one(struct cache_tree *it,
>
> int cache_tree_update(struct index_state *istate, int flags)
> {
> - uint64_t start = getnanotime();
> struct cache_tree *it = istate->cache_tree;
> struct cache_entry **cache = istate->cache;
> int entries = istate->cache_nr;
> @@ -434,11 +433,12 @@ 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;
> - trace_performance_since(start, "repair cache-tree");
> return 0;
> }
>
> diff --git a/cache.h b/cache.h
> index e6f7ee4b64..8b447652a7 100644
> --- a/cache.h
> +++ b/cache.h
> @@ -673,7 +673,6 @@ extern int index_name_pos(const struct index_state *, const char *name, int name
> #define ADD_CACHE_JUST_APPEND 8 /* Append only; tree.c::read_tree() */
> #define ADD_CACHE_NEW_ONLY 16 /* Do not replace existing ones */
> #define ADD_CACHE_KEEP_CACHE_TREE 32 /* Do not invalidate cache-tree */
> -#define ADD_CACHE_SKIP_VERIFY_PATH 64 /* Do not verify path */
> extern int add_index_entry(struct index_state *, struct cache_entry *ce, int option);
> extern void rename_index_entry_at(struct index_state *, int pos, const char *new_name);
>
> diff --git a/diff-lib.c b/diff-lib.c
> index a9f38eb5a3..1ffa22c882 100644
> --- a/diff-lib.c
> +++ b/diff-lib.c
> @@ -518,8 +518,8 @@ 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();
>
> + trace_performance_enter();
> ent = revs->pending.objects;
> if (diff_cache(revs, &ent->item->oid, ent->name, cached))
> exit(128);
> @@ -528,7 +528,7 @@ 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;
> }
>
> diff --git a/dir.c b/dir.c
> index 21e6f2520a..c5e9fc8cea 100644
> --- a/dir.c
> +++ b/dir.c
> @@ -2263,11 +2263,11 @@ 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))
> return dir->nr;
>
> + trace_performance_enter();
> untracked = validate_untracked_cache(dir, len, pathspec);
> if (!untracked)
> /*
> @@ -2302,7 +2302,7 @@ 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);
> diff --git a/name-hash.c b/name-hash.c
> index 163849831c..1fcda73cb3 100644
> --- a/name-hash.c
> +++ b/name-hash.c
> @@ -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");
> }
>
> /*
> diff --git a/preload-index.c b/preload-index.c
> index 4d08d44874..d7f7919ba2 100644
> --- a/preload-index.c
> +++ b/preload-index.c
> @@ -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
>
> diff --git a/read-cache.c b/read-cache.c
> index b0b5df5de7..2b5646ef26 100644
> --- a/read-cache.c
> +++ b/read-cache.c
> @@ -1170,7 +1170,6 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e
> int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
> int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
> int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
> - int skip_verify_path = option & ADD_CACHE_SKIP_VERIFY_PATH;
> int new_only = option & ADD_CACHE_NEW_ONLY;
>
> if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
> @@ -1211,7 +1210,7 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e
>
> if (!ok_to_add)
> return -1;
> - if (!skip_verify_path && !verify_path(ce->name, ce->ce_mode))
> + if (!verify_path(ce->name, ce->ce_mode))
> return error("Invalid path '%s'", ce->name);
>
> if (!skip_df_check &&
> @@ -1400,8 +1399,8 @@ 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");
> @@ -1471,7 +1470,7 @@ 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;
> }
>
> @@ -1902,7 +1901,6 @@ 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;
> @@ -1912,8 +1910,9 @@ 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)) {
> @@ -1921,6 +1920,7 @@ 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
> @@ -1937,8 +1937,8 @@ 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;
> }
>
> @@ -2763,4 +2763,6 @@ 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;
> }
> diff --git a/trace.c b/trace.c
> index fc623e91fd..fa4a2e7120 100644
> --- a/trace.c
> +++ b/trace.c
> @@ -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();
> }
> diff --git a/trace.h b/trace.h
> index 2b6a1bc17c..171b256d26 100644
> --- a/trace.h
> +++ b/trace.h
> @@ -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;
> diff --git a/unpack-trees.c b/unpack-trees.c
> index 1438ee1555..d822662c75 100644
> --- a/unpack-trees.c
> +++ b/unpack-trees.c
> @@ -201,7 +201,6 @@ static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
>
> ce->ce_flags = (ce->ce_flags & ~clear) | set;
> return add_index_entry(&o->result, ce,
> - o->extra_add_index_flags |
> ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
> }
>
> @@ -353,9 +352,9 @@ static int check_updates(struct unpack_trees_options *o)
> struct progress *progress = NULL;
> struct index_state *index = &o->result;
> struct checkout state = CHECKOUT_INIT;
> - uint64_t start = getnanotime();
> int i;
>
> + trace_performance_enter();
> state.force = 1;
> state.quiet = 1;
> state.refresh_cache = 1;
> @@ -425,7 +424,7 @@ static int check_updates(struct unpack_trees_options *o)
> errs |= finish_delayed_checkout(&state);
> if (o->update)
> git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
> - trace_performance_since(start, "update worktree after a merge");
> + trace_performance_leave("check_updates");
> return errs != 0;
> }
>
> @@ -702,31 +701,13 @@ static int traverse_by_cache_tree(int pos, int nr_entries, int nr_names,
> if (!o->merge)
> BUG("We need cache-tree to do this optimization");
>
> - /*
> - * Try to keep add_index_entry() as fast as possible since
> - * we're going to do a lot of them.
> - *
> - * Skipping verify_path() should totally be safe because these
> - * paths are from the source index, which must have been
> - * verified.
> - *
> - * Skipping D/F and cache-tree validation checks is trickier
> - * because it assumes what n-merge code would do when all
> - * trees and the index are the same. We probably could just
> - * optimize those code instead (e.g. we don't invalidate that
> - * many cache-tree, but the searching for them is very
> - * expensive).
> - */
> - o->extra_add_index_flags = ADD_CACHE_SKIP_DFCHECK;
> - o->extra_add_index_flags |= ADD_CACHE_SKIP_VERIFY_PATH;
> -
> /*
> * Do what unpack_callback() and unpack_nondirectories() normally
> * do. But we walk all paths recursively in just one loop instead.
> *
> - * D/F conflicts and staged entries are not a concern because
> - * cache-tree would be invalidated and we would never get here
> - * in the first place.
> + * 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;
> @@ -761,7 +742,6 @@ static int traverse_by_cache_tree(int pos, int nr_entries, int nr_names,
>
> mark_ce_used(src[0], o);
> }
> - o->extra_add_index_flags = 0;
> free(tree_ce);
> if (o->debug_unpack)
> printf("Unpacked %d entries from %s to %s using cache-tree\n",
> @@ -791,7 +771,17 @@ static int traverse_trees_recursive(int n, unsigned long dirmask,
>
> if (!o->merge || df_conflicts)
> BUG("Wrong condition to get here buddy");
> - return traverse_by_cache_tree(pos, nr_entries, n, names, info);
> +
> + /*
> + * 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;
> @@ -1142,7 +1132,7 @@ static void debug_unpack_callback(int n,
> }
>
> /*
> - * Note that traverse_by_cache_tree() duplicates some logic in this funciton
> + * 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.
> */
> @@ -1425,11 +1415,11 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
> int i, ret;
> static struct cache_entry *dfc;
> struct exclude_list el;
> - uint64_t start = getnanotime();
>
> 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;
> @@ -1502,7 +1492,10 @@ 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;
> }
>
> @@ -1574,10 +1567,10 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
> goto done;
> }
> }
> - trace_performance_since(start, "unpack trees");
>
> ret = check_updates(o) ? (-2) : 0;
> if (o->dst_index) {
> + move_index_extensions(&o->result, o->src_index);
> if (!ret) {
> if (!o->result.cache_tree)
> o->result.cache_tree = cache_tree();
> @@ -1586,7 +1579,6 @@ 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 {
> @@ -1595,6 +1587,7 @@ 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;
>
> diff --git a/unpack-trees.h b/unpack-trees.h
> index 94e1b14078..c2b434c606 100644
> --- a/unpack-trees.h
> +++ b/unpack-trees.h
> @@ -80,7 +80,6 @@ struct unpack_trees_options {
> struct index_state result;
>
> struct exclude_list *el; /* for internal use */
> - unsigned int extra_add_index_flags;
> };
>
> extern int unpack_trees(unsigned n, struct tree_desc *t,
>
> Nguyễn Thái Ngọc Duy (5):
> trace.h: support nested performance tracing
> unpack-trees: add performance tracing
> unpack-trees: optimize walking same trees with cache-tree
> unpack-trees: reduce malloc in cache-tree walk
> unpack-trees: reuse (still valid) cache-tree from src_index
>
> cache-tree.c | 2 +
> diff-lib.c | 4 +-
> dir.c | 4 +-
> name-hash.c | 4 +-
> preload-index.c | 4 +-
> read-cache.c | 13 +++--
> trace.c | 69 ++++++++++++++++++++--
> trace.h | 15 +++++
> unpack-trees.c | 149 +++++++++++++++++++++++++++++++++++++++++++++++-
> 9 files changed, 243 insertions(+), 21 deletions(-)
>