When decoding reftable ref records we first release the pointer to the
record passed to us and then use realloc(3P) to allocate the refname
array. This is a bit misleading though as we know at that point that the
refname will always be `NULL`, so we would always end up allocating a
new char array anyway.
Refactor the code to use `REFTABLE_ALLOC_ARRAY()` instead. As the
following benchmark demonstrates this is a tiny bit more efficient. But
the bigger selling point really is the gained clarity.
Benchmark 1: show-ref: single matching ref (revision = HEAD~)
Time (mean ± σ): 150.1 ms ± 4.1 ms [User: 146.6 ms, System: 3.3 ms]
Range (min … max): 144.5 ms … 180.5 ms 1000 runs
Benchmark 2: show-ref: single matching ref (revision = HEAD)
Time (mean ± σ): 148.9 ms ± 4.5 ms [User: 145.2 ms, System: 3.4 ms]
Range (min … max): 143.0 ms … 185.4 ms 1000 runs
Summary
show-ref: single matching ref (revision = HEAD) ran
1.01 ± 0.04 times faster than show-ref: single matching ref (revision = HEAD~)
Ideally, we should try and reuse the memory of the old record instead of
first freeing and then immediately reallocating it. This requires some
more surgery though and is thus left for a future iteration.
Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
reftable/record.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/reftable/record.c b/reftable/record.c
index f1b6a5eac9..6465a7b8f4 100644
--- a/reftable/record.c
+++ b/reftable/record.c
@@ -377,10 +377,11 @@ static int reftable_ref_record_decode(void *rec, struct strbuf key,
assert(hash_size > 0);
- r->refname = reftable_realloc(r->refname, key.len + 1);
+ r->refname = reftable_malloc(key.len + 1);
memcpy(r->refname, key.buf, key.len);
- r->update_index = update_index;
r->refname[key.len] = 0;
+
+ r->update_index = update_index;
r->value_type = val_type;
switch (val_type) {
case REFTABLE_REF_VAL1:
--
2.43.GIT
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