reftable/record: reuse refnames when decoding log records

When decoding a log record we always reallocate their refname arrays. This results in quite a lot of needless allocation churn. Refactor the code to grow the array as required only. Like this, we should usually only end up reallocating the array a small handful of times when iterating over many refs. Before: HEAP SUMMARY: in use at exit: 13,473 bytes in 122 blocks total heap usage: 4,068,487 allocs, 4,068,365 frees, 332,011,793 bytes allocated After: HEAP SUMMARY: in use at exit: 13,473 bytes in 122 blocks total heap usage: 3,068,488 allocs, 3,068,366 frees, 307,122,961 bytes allocated Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Patrick Steinhardt committed Mar 5, 2024 at 13:11 UTC 193fcb3ff82184c3c7b7e3d0da9d0b7aaa648b91
2 files changed +2 -1
reftable/record.c
+1 -1
index d816de6d93..82780b2d06 100644 --- a/reftable/record.c +++ b/reftable/record.c @@ -861,7 +861,7 @@ static int reftable_log_record_decode(void *rec, struct strbuf key, if (key.len <= 9 || key.buf[key.len - 9] != 0) return REFTABLE_FORMAT_ERROR; - r->refname = reftable_realloc(r->refname, key.len - 8); + REFTABLE_ALLOC_GROW(r->refname, key.len - 8, r->refname_cap); memcpy(r->refname, key.buf, key.len - 8); ts = get_be64(key.buf + key.len - 8);
reftable/reftable-record.h
+1
index 2659ea008c..d28f38175c 100644 --- a/reftable/reftable-record.h +++ b/reftable/reftable-record.h @@ -74,6 +74,7 @@ int reftable_ref_record_equal(const struct reftable_ref_record *a, /* reftable_log_record holds a reflog entry */ struct reftable_log_record { char *refname; + size_t refname_cap; uint64_t update_index; /* logical timestamp of a transactional update. */