[PATCH 2/2] test-mergesort: use mem_pool for sort input
- From
René Scharfe <l.s.r@web.de>
- Date
- Aug 28, 2022, 10:34 UTC
- Message-ID
- <a597ca34-04d7-4505-2e6b-f8f33d7e817e@web.de>
- In-Reply-To
- <128f0fb8-d29b-8622-0cfe-2ecadc999db5@web.de>
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@web.de> --- 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