On 9/1/2022 12:57 AM, Shaoxuan Yuan wrote:
> Test HEAD~ HEAD
> ---------------------------------------------------------------------------------------------------
> 2000.78: git grep --cached --sparse bogus -- f2/f1/f1/builtin/* (full-v3) 0.11 0.09 (≈)
> 2000.79: git grep --cached --sparse bogus -- f2/f1/f1/builtin/* (full-v4) 0.08 0.09 (≈)
> 2000.80: git grep --cached --sparse bogus -- f2/f1/f1/builtin/* (sparse-v3) 0.44 0.04 (-90.9%)
> 2000.81: git grep --cached --sparse bogus -- f2/f1/f1/builtin/* (sparse-v4) 0.46 0.04 (-91.3%)
>
> - Command used for testing:
>
> git grep --cached --sparse bogus -- f2/f1/f1/builtin/*
It's good to list this command after the table. It allows you to shrink
the table by using "...":
Test HEAD~ HEAD
---------------------------------------------------------
2000.78: git grep ... (full-v3) 0.11 0.09 (≈)
2000.79: git grep ... (full-v4) 0.08 0.09 (≈)
2000.80: git grep ... (sparse-v3) 0.44 0.04 (-90.9%)
2000.81: git grep ... (sparse-v4) 0.46 0.04 (-91.3%)
This saves horizontal space without losing clarity. The test numbers help,
too.
> strbuf_setlen(&name, name_base_len);
> strbuf_addstr(&name, ce->name);
> + if (S_ISSPARSEDIR(ce->ce_mode)) {
> + enum object_type type;
> + struct tree_desc tree;
> + void *data;
> + unsigned long size;
> + struct strbuf base = STRBUF_INIT;
> +
> + strbuf_addstr(&base, ce->name);
> +
> + data = read_object_file(&ce->oid, &type, &size);
> + init_tree_desc(&tree, data, size);
>
> - if (S_ISREG(ce->ce_mode) &&
> + /*
> + * sneak in the ce_mode using check_attr parameter
> + */
> + hit |= grep_tree(opt, pathspec, &tree, &base,
> + base.len, ce->ce_mode);
> + strbuf_release(&base);
> + free(data);
> + } else if (S_ISREG(ce->ce_mode) &&
I think this is a good setup for transitioning from the index scan
to the tree-walking grep_tree() method. Below, I recommend calling
the method slightly differently, though.
> match_pathspec(repo->index, pathspec, name.buf, name.len, 0, NULL,
> S_ISDIR(ce->ce_mode) ||
> S_ISGITLINK(ce->ce_mode))) {
> @@ -598,7 +613,14 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
> int te_len = tree_entry_len(&entry);
>
> if (match != all_entries_interesting) {
> - strbuf_addstr(&name, base->buf + tn_len);
> + if (S_ISSPARSEDIR(check_attr)) {
> + // object is a sparse directory entry
> + strbuf_addbuf(&name, base);
> + } else {
> + // object is a commit or a root tree
> + strbuf_addstr(&name, base->buf + tn_len);
> + }
> +
I think this is abusing the check_attr too much, since this will also
trigger a different if branch further down the method.
These lines are the same if tn_len is zero, so will it suffice to pass
0 for that length? You are passing base.len when you call it, so maybe
that should be zero?
When I apply this change, all tests pass, so if there _is_ something
different between the two implementations, then it isn't covered by
tests:
diff --git a/builtin/grep.c b/builtin/grep.c
index 8c0edccd8e..fc4adf876a 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -549,8 +549,7 @@ static int grep_cache(struct grep_opt *opt,
/*
* sneak in the ce_mode using check_attr parameter
*/
- hit |= grep_tree(opt, pathspec, &tree, &base,
- base.len, ce->ce_mode);
+ hit |= grep_tree(opt, pathspec, &tree, &base, 0, 0);
strbuf_release(&base);
free(data);
} else if (S_ISREG(ce->ce_mode) &&
@@ -613,13 +612,7 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
int te_len = tree_entry_len(&entry);
if (match != all_entries_interesting) {
- if (S_ISSPARSEDIR(check_attr)) {
- // object is a sparse directory entry
- strbuf_addbuf(&name, base);
- } else {
- // object is a commit or a root tree
- strbuf_addstr(&name, base->buf + tn_len);
- }
+ strbuf_addstr(&name, base->buf + tn_len);
match = tree_entry_interesting(repo->index,
&entry, &name,
> +test_perf_on_all git grep --cached --sparse bogus -- "f2/f1/f1/builtin/*"
We can't use this path in general, because we don't always run the test
using the Git repository as the test repo (see GIT_PERF_[LARGE_]REPO
variables in t/perf/README).
We _can_ however use the structure that we have implied in our construction,
which is to use a path that we know exists and is still outside of the
sparse-checkout cone. Truncating to "f2/f1/f1/*" is sufficient for this.
Modifying the test and running them on my machine, I get:
Test HEAD~1 HEAD
----------------------------------------------------------------------------
2000.78: git grep ... (full-v3) 0.19(0.72+0.18) 0.18(0.84+0.13) -5.3%
2000.79: git grep ... (full-v4) 0.17(0.83+0.16) 0.19(0.84+0.14) +11.8%
2000.80: git grep ... (sparse-v3) 0.35(1.02+0.13) 0.15(0.85+0.15) -57.1%
2000.81: git grep ... (sparse-v4) 0.37(1.06+0.12) 0.15(0.89+0.15) -59.5%
So, it's still expensive to do the blob search over a wider pathspec than
the test as you designed it, but this will work for other repo, such as the
Linux kernel:
Test HEAD~1 HEAD
------------------------------------------------------------------------------
2000.78: git grep ... (full-v3) 3.16(19.37+2.55) 2.56(15.24+1.76) -19.0%
2000.79: git grep ... (full-v4) 2.97(17.84+2.00) 2.59(15.51+1.89) -12.8%
2000.80: git grep ... (sparse-v3) 8.39(24.74+2.34) 2.13(16.03+1.72) -74.6%
2000.81: git grep ... (sparse-v4) 8.39(24.73+2.40) 2.16(16.14+1.90) -74.3%
Thanks,
-Stolee
