On 9/1/2022 10:03 AM, Derrick Stolee wrote:
> 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 "...":
OK.
>
> 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.
Yeah that's why I wrote "sneak in".
> 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?
Agree.
> 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:
I think they are no difference between these two implementations,
at least according to my intention.
> 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.
OK.
> 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:
Yes, I was trying to use a narrower pathspec to show a difference that
looks better.
> 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
Thanks,
Shaoxuan
