development/git
development/git
1
0
Fork 0
mirror of https://github.com/git/git synced 2024-11-05 04:53:18 +00:00
Code Issues Projects Releases Packages Wiki Activity

reftable/block: reuse compressed array

Browse source 
Similar to the preceding commit, let's reuse the `compressed` array that
we use to store compressed data in. This results in a small reduction in
memory allocations when writing many refs.

Before:

  HEAP SUMMARY:
      in use at exit: 671,931 bytes in 151 blocks
    total heap usage: 22,620,528 allocs, 22,620,377 frees, 1,245,549,984 bytes allocated

After:

  HEAP SUMMARY:
      in use at exit: 671,931 bytes in 151 blocks
    total heap usage: 22,618,257 allocs, 22,618,106 frees, 1,236,351,528 bytes allocated

So while the reduction in allocations isn't really all that big, it's a
low hanging fruit and thus there isn't much of a reason not to pick it.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Patrick Steinhardt 2024-04-08 14:24:40 +02:00 committed by Junio C Hamano
parent a155ab2bf4
commit fa74f32291
2 changed files with 8 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

14
reftable/block.c
View file

@ -150,7 +150,6 @@ int block_writer_finish(struct block_writer *w)
if (block_writer_type(w) == BLOCK_TYPE_LOG) {
int block_header_skip = 4 + w->header_off;
uLongf src_len = w->next - block_header_skip, compressed_len;
unsigned char *compressed;
int ret;
ret = deflateReset(w->zstream);
@ -163,9 +162,9 @@ int block_writer_finish(struct block_writer *w)
* is guaranteed to return `Z_STREAM_END`.
*/
compressed_len = deflateBound(w->zstream, src_len);
REFTABLE_ALLOC_ARRAY(compressed, compressed_len);
REFTABLE_ALLOC_GROW(w->compressed, compressed_len, w->compressed_cap);
w->zstream->next_out = compressed;
w->zstream->next_out = w->compressed;
w->zstream->avail_out = compressed_len;
w->zstream->next_in = w->buf + block_header_skip;
w->zstream->avail_in = src_len;
@ -177,21 +176,17 @@ int block_writer_finish(struct block_writer *w)
* guaranteed to succeed according to the zlib documentation.
*/
ret = deflate(w->zstream, Z_FINISH);
if (ret != Z_STREAM_END) {
reftable_free(compressed);
if (ret != Z_STREAM_END)
return REFTABLE_ZLIB_ERROR;
}
/*
* Overwrite the uncompressed data we have already written and
* adjust the `next` pointer to point right after the
* compressed data.
*/
memcpy(w->buf + block_header_skip, compressed,
memcpy(w->buf + block_header_skip, w->compressed,
w->zstream->total_out);
w->next = w->zstream->total_out + block_header_skip;
reftable_free(compressed);
}
return w->next;
@ -450,6 +445,7 @@ void block_writer_release(struct block_writer *bw)
deflateEnd(bw->zstream);
FREE_AND_NULL(bw->zstream);
FREE_AND_NULL(bw->restarts);
FREE_AND_NULL(bw->compressed);
strbuf_release(&bw->last_key);
/* the block is not owned. */
}

3
reftable/block.h
View file

@ -19,6 +19,9 @@ license that can be found in the LICENSE file or at
*/
struct block_writer {
z_stream *zstream;
unsigned char *compressed;
size_t compressed_cap;
uint8_t *buf;
uint32_t block_size;