The previous patch almost halved the number of heap allocations for the
sort subcommand. Reduce it further by using a mem_pool for the line
objects.
Note that t/perf/run can't be used directly to compare two versions of
test-mergesort because it always runs the helpers from the checked-out
version. So I hand-merged the results of separate runs before and with
this patch:
macOS 12.5.1 on M1:
0071.12: DEFINE_LIST_SORT unsorted 0.22(0.20+0.01) 0.21(0.19+0.01)
0071.14: DEFINE_LIST_SORT sorted 0.10(0.08+0.01) 0.10(0.08+0.01)
0071.16: DEFINE_LIST_SORT reversed 0.10(0.08+0.01) 0.10(0.08+0.01)
Git SDK 64-bit on Windows 11 21H2 on Ryzen 7 5800H:
0071.12: DEFINE_LIST_SORT unsorted 0.54(0.00+0.06) 0.44(0.01+0.06)
0071.14: DEFINE_LIST_SORT sorted 0.21(0.03+0.03) 0.19(0.04+0.01)
0071.16: DEFINE_LIST_SORT reversed 0.21(0.01+0.04) 0.19(0.04+0.04)
Debian bullseye on WSL2 on the same system:
0071.12: DEFINE_LIST_SORT unsorted 0.29(0.27+0.01) 0.22(0.19+0.02)
0071.14: DEFINE_LIST_SORT sorted 0.07(0.06+0.01) 0.06(0.04+0.02)
0071.16: DEFINE_LIST_SORT reversed 0.07(0.04+0.03) 0.06(0.04+0.02)
Signed-off-by: René Scharfe <l.s.r@xxxxxx>
---
t/helper/test-mergesort.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/t/helper/test-mergesort.c b/t/helper/test-mergesort.c
index 540537224f..335e5bb3a9 100644
--- a/t/helper/test-mergesort.c
+++ b/t/helper/test-mergesort.c
@@ -25,6 +25,7 @@ static int sort_stdin(void)
struct line *lines;
struct line **tail = &lines;
struct strbuf sb = STRBUF_INIT;
+ struct mem_pool lines_pool;
char *p;
strbuf_read(&sb, 0, 0);
@@ -36,10 +37,11 @@ static int sort_stdin(void)
if (sb.len && sb.buf[sb.len - 1] == '\n')
strbuf_setlen(&sb, sb.len - 1);
+ mem_pool_init(&lines_pool, 0);
p = sb.buf;
for (;;) {
char *eol = strchr(p, '\n');
- struct line *line = xmalloc(sizeof(*line));
+ struct line *line = mem_pool_alloc(&lines_pool, sizeof(*line));
line->text = p;
*tail = line;
tail = &line->next;
--
2.30.2
