Kirill Smelkov <kirr@xxxxxxxxxx> writes:
> instead of allocating it all the time for every subtree in
> __diff_tree_sha1, let's allocate it once in diff_tree_sha1, and then all
> callee just use it in stacking style, without memory allocations.
>
> This should be faster, and for me this change gives the following
> slight speedups for
>
> git log --raw --no-abbrev --no-renames --format='%H'
>
> navy.git linux.git v3.10..v3.11
>
> before 0.618s 1.903s
> after 0.611s 1.889s
> speedup 1.1% 0.7%
>
> Signed-off-by: Kirill Smelkov <kirr@xxxxxxxxxx>
> ---
>
> Changes since v1:
>
> - don't need to touch diff.h, as the function we are changing became static.
>
> tree-diff.c | 36 ++++++++++++++++++------------------
> 1 file changed, 18 insertions(+), 18 deletions(-)
>
> diff --git a/tree-diff.c b/tree-diff.c
> index aea0297..c76821d 100644
> --- a/tree-diff.c
> +++ b/tree-diff.c
> @@ -115,7 +115,7 @@ static void show_path(struct strbuf *base, struct diff_options *opt,
> if (recurse) {
> strbuf_addch(base, '/');
> __diff_tree_sha1(t1 ? t1->entry.sha1 : NULL,
> - t2 ? t2->entry.sha1 : NULL, base->buf, opt);
> + t2 ? t2->entry.sha1 : NULL, base, opt);
> }
>
> strbuf_setlen(base, old_baselen);
I was scratching my head for a while, after seeing that there does
not seem to be any *new* code added by this patch in order to
store-away the original length and restore the singleton base buffer
to the original length after using addch/addstr to extend it.
But I see that the code has already been prepared to do this
conversion. I wonder why we didn't do this earlier ;-)
Looks good. Thanks.
> @@ -138,12 +138,10 @@ static void skip_uninteresting(struct tree_desc *t, struct strbuf *base,
> }
>
> static int __diff_tree_sha1(const unsigned char *old, const unsigned char *new,
> - const char *base_str, struct diff_options *opt)
> + struct strbuf *base, struct diff_options *opt)
> {
> struct tree_desc t1, t2;
> void *t1tree, *t2tree;
> - struct strbuf base;
> - int baselen = strlen(base_str);
>
> t1tree = fill_tree_descriptor(&t1, old);
> t2tree = fill_tree_descriptor(&t2, new);
> @@ -151,17 +149,14 @@ static int __diff_tree_sha1(const unsigned char *old, const unsigned char *new,
> /* Enable recursion indefinitely */
> opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);
>
> - strbuf_init(&base, PATH_MAX);
> - strbuf_add(&base, base_str, baselen);
> -
> for (;;) {
> int cmp;
>
> if (diff_can_quit_early(opt))
> break;
> if (opt->pathspec.nr) {
> - skip_uninteresting(&t1, &base, opt);
> - skip_uninteresting(&t2, &base, opt);
> + skip_uninteresting(&t1, base, opt);
> + skip_uninteresting(&t2, base, opt);
> }
> if (!t1.size && !t2.size)
> break;
> @@ -173,7 +168,7 @@ static int __diff_tree_sha1(const unsigned char *old, const unsigned char *new,
> if (DIFF_OPT_TST(opt, FIND_COPIES_HARDER) ||
> hashcmp(t1.entry.sha1, t2.entry.sha1) ||
> (t1.entry.mode != t2.entry.mode))
> - show_path(&base, opt, &t1, &t2);
> + show_path(base, opt, &t1, &t2);
>
> update_tree_entry(&t1);
> update_tree_entry(&t2);
> @@ -181,18 +176,17 @@ static int __diff_tree_sha1(const unsigned char *old, const unsigned char *new,
>
> /* t1 < t2 */
> else if (cmp < 0) {
> - show_path(&base, opt, &t1, /*t2=*/NULL);
> + show_path(base, opt, &t1, /*t2=*/NULL);
> update_tree_entry(&t1);
> }
>
> /* t1 > t2 */
> else {
> - show_path(&base, opt, /*t1=*/NULL, &t2);
> + show_path(base, opt, /*t1=*/NULL, &t2);
> update_tree_entry(&t2);
> }
> }
>
> - strbuf_release(&base);
> free(t2tree);
> free(t1tree);
> return 0;
> @@ -209,7 +203,7 @@ static inline int diff_might_be_rename(void)
> !DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
> }
>
> -static void try_to_follow_renames(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
> +static void try_to_follow_renames(const unsigned char *old, const unsigned char *new, struct strbuf *base, struct diff_options *opt)
> {
> struct diff_options diff_opts;
> struct diff_queue_struct *q = &diff_queued_diff;
> @@ -306,13 +300,19 @@ static void try_to_follow_renames(const unsigned char *old, const unsigned char
> q->nr = 1;
> }
>
> -int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
> +int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base_str, struct diff_options *opt)
> {
> + struct strbuf base;
> int retval;
>
> - retval = __diff_tree_sha1(old, new, base, opt);
> - if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename())
> - try_to_follow_renames(old, new, base, opt);
> + strbuf_init(&base, PATH_MAX);
> + strbuf_addstr(&base, base_str);
> +
> + retval = __diff_tree_sha1(old, new, &base, opt);
> + if (!*base_str && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename())
> + try_to_follow_renames(old, new, &base, opt);
> +
> + strbuf_release(&base);
>
> return retval;
> }
--
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