We're recomputing the prefix length on every iteration of the ref
iterator. Precompute it for another speedup when iterating over 1
million refs:
Benchmark 1: show-ref: single matching ref (revision = HEAD~)
Time (mean ± σ): 100.3 ms ± 3.7 ms [User: 97.3 ms, System: 2.8 ms]
Range (min … max): 97.5 ms … 139.7 ms 1000 runs
Benchmark 2: show-ref: single matching ref (revision = HEAD)
Time (mean ± σ): 95.8 ms ± 3.4 ms [User: 92.9 ms, System: 2.8 ms]
Range (min … max): 93.0 ms … 121.9 ms 1000 runs
Summary
show-ref: single matching ref (revision = HEAD) ran
1.05 ± 0.05 times faster than show-ref: single matching ref (revision = HEAD~)
Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
refs/reftable-backend.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 6c11c4a5e3..249a618b5a 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -346,6 +346,7 @@ struct reftable_ref_iterator {
struct object_id oid;
const char *prefix;
+ size_t prefix_len;
unsigned int flags;
int err;
};
@@ -371,8 +372,8 @@ static int reftable_ref_iterator_advance(struct ref_iterator *ref_iterator)
if (!starts_with(iter->ref.refname, "refs/"))
continue;
- if (iter->prefix &&
- strncmp(iter->prefix, iter->ref.refname, strlen(iter->prefix))) {
+ if (iter->prefix_len &&
+ strncmp(iter->prefix, iter->ref.refname, iter->prefix_len)) {
iter->err = 1;
break;
}
@@ -481,6 +482,7 @@ static struct reftable_ref_iterator *ref_iterator_for_stack(struct reftable_ref_
iter = xcalloc(1, sizeof(*iter));
base_ref_iterator_init(&iter->base, &reftable_ref_iterator_vtable);
iter->prefix = prefix;
+ iter->prefix_len = prefix ? strlen(prefix) : 0;
iter->base.oid = &iter->oid;
iter->flags = flags;
iter->refs = refs;
--
2.44.0
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