When `git blame --color-by-age`, the determine_line_heat() is called to
select how to color the output based on the commit's author date. It
uses the get_commit_info() to parse the information into a `commit_info`
structure, however, this is actually unnecessary because the
determine_line_heat() caller also does the same.
Instead, let's change the determine_line_heat() to take a `commit_info`
structure and remove the internal call to get_commit_info() thus
cleaning up and optimizing the code path.
Enabling Git's trace2 API in order to record the execution time for
every call to determine_line_heat() function:
+ trace2_region_enter("blame", "determine_line_heat", the_repository);
determine_line_heat(ent, &default_color);
+ trace2_region_enter("blame", "determine_line_heat", the_repository);
Then, running `git blame` for "kernel/fork.c" in linux.git and summing
all the execution time for every call (around 1.3k calls) resulted in
2.6x faster execution (best out 3):
git built from 328c109303 (The eighth batch, 2021-02-12) = 42ms
git built from 328c109303 + this change = 16ms
Signed-off-by: Rafael Silva <rafaeloliveira.cs@xxxxxxxxx>
---
builtin/blame.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/builtin/blame.c b/builtin/blame.c
index b66e938022..641523ff9a 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -425,13 +425,11 @@ static void setup_default_color_by_age(void)
parse_color_fields("blue,12 month ago,white,1 month ago,red");
}
-static void determine_line_heat(struct blame_entry *ent, const char **dest_color)
+static void determine_line_heat(struct commit_info *ci, const char **dest_color)
{
int i = 0;
- struct commit_info ci;
- get_commit_info(ent->suspect->commit, &ci, 1);
- while (i < colorfield_nr && ci.author_time > colorfield[i].hop)
+ while (i < colorfield_nr && ci->author_time > colorfield[i].hop)
i++;
*dest_color = colorfield[i].col;
@@ -453,7 +451,7 @@ static void emit_other(struct blame_scoreboard *sb, struct blame_entry *ent, int
cp = blame_nth_line(sb, ent->lno);
if (opt & OUTPUT_SHOW_AGE_WITH_COLOR) {
- determine_line_heat(ent, &default_color);
+ determine_line_heat(&ci, &default_color);
color = default_color;
reset = GIT_COLOR_RESET;
}
--
2.30.1.850.g2d41e9e789
