@@ -110,24 +110,21 @@ int block_writer_add(struct block_writer *w, struct reftable_record *rec)
.buf = w->block + w->next,
.len = w->block_size - w->next,
};
-
struct string_view start = out;
-
int is_restart = 0;
- struct reftable_buf key = REFTABLE_BUF_INIT;
int n = 0;
int err;
- err = reftable_record_key(rec, &key);
+ err = reftable_record_key(rec, &w->scratch);
if (err < 0)
goto done;
- if (!key.len) {
+ if (!w->scratch.len) {
err = REFTABLE_API_ERROR;
goto done;
}
- n = reftable_encode_key(&is_restart, out, last, key,
+ n = reftable_encode_key(&is_restart, out, last, w->scratch,
reftable_record_val_type(rec));
if (n < 0) {
err = -1;
@@ -143,9 +140,8 @@ int block_writer_add(struct block_writer *w, struct reftable_record *rec)
string_view_consume(&out, n);
err = block_writer_register_restart(w, start.len - out.len, is_restart,
- &key);
+ &w->scratch);
done:
- reftable_buf_release(&key);
return err;
}
@@ -569,6 +565,7 @@ void block_writer_release(struct block_writer *bw)
REFTABLE_FREE_AND_NULL(bw->zstream);
REFTABLE_FREE_AND_NULL(bw->restarts);
REFTABLE_FREE_AND_NULL(bw->compressed);
+ reftable_buf_release(&bw->scratch);
reftable_buf_release(&bw->last_key);
/* the block is not owned. */
}
@@ -39,6 +39,8 @@ struct block_writer {
uint32_t restart_cap;
struct reftable_buf last_key;
+ /* Scratch buffer used to avoid allocations. */
+ struct reftable_buf scratch;
int entries;
};
The block writer needs to compute the key for every record that one adds to the writer. The buffer for this key is stored on the stack and thus reallocated on every call to `block_writer_add()`, which is inefficient. Refactor the code so that we store the buffer in the `block_writer` struct itself so that we can reuse it. This reduces the number of allocations when writing many refs, e.g. when migrating one million refs from the "files" backend to the "reftable backend. Before this change: HEAP SUMMARY: in use at exit: 80,048 bytes in 49 blocks total heap usage: 3,025,864 allocs, 3,025,815 frees, 372,746,291 bytes allocated After this change: HEAP SUMMARY: in use at exit: 80,048 bytes in 49 blocks total heap usage: 2,013,250 allocs, 2,013,201 frees, 347,543,583 bytes allocated Signed-off-by: Patrick Steinhardt <ps@pks.im> --- reftable/block.c | 13 +++++-------- reftable/block.h | 2 ++ 2 files changed, 7 insertions(+), 8 deletions(-)