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authorNicolas Pitre <nico@cam.org>2008-08-29 20:08:02 (GMT)
committerJunio C Hamano <gitster@pobox.com>2008-08-30 04:51:28 (GMT)
commitd35825da6d5570524234e1bfe4ff0f57957b6db3 (patch)
tree1a02c65f37b000e5fae836fc8da11dc0d244fd20 /pack-write.c
parent8522148f79c29ef8f63688e7186e458a22333224 (diff)
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fixup_pack_header_footer(): use nicely aligned buffer sizes
It should be more efficient to use nicely aligned buffer sizes, either for filesystem operations or SHA1 checksums. Also, using a relatively small nominal size might allow for the data to remain in L1 cache between both SHA1_Update() calls. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'pack-write.c')
-rw-r--r--pack-write.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/pack-write.c b/pack-write.c
index f9776c5..939ed56 100644
--- a/pack-write.c
+++ b/pack-write.c
@@ -167,7 +167,7 @@ void fixup_pack_header_footer(int pack_fd,
unsigned char *partial_pack_sha1,
off_t partial_pack_offset)
{
- static const int buf_sz = 128 * 1024;
+ int aligned_sz, buf_sz = 8 * 1024;
SHA_CTX old_sha1_ctx, new_sha1_ctx;
struct pack_header hdr;
char *buf;
@@ -188,10 +188,11 @@ void fixup_pack_header_footer(int pack_fd,
partial_pack_offset -= sizeof(hdr);
buf = xmalloc(buf_sz);
+ aligned_sz = buf_sz - sizeof(hdr);
for (;;) {
ssize_t m, n;
- m = (partial_pack_sha1 && partial_pack_offset < buf_sz) ?
- partial_pack_offset : buf_sz;
+ m = (partial_pack_sha1 && partial_pack_offset < aligned_sz) ?
+ partial_pack_offset : aligned_sz;
n = xread(pack_fd, buf, m);
if (!n)
break;
@@ -199,6 +200,10 @@ void fixup_pack_header_footer(int pack_fd,
die("Failed to checksum %s: %s", pack_name, strerror(errno));
SHA1_Update(&new_sha1_ctx, buf, n);
+ aligned_sz -= n;
+ if (!aligned_sz)
+ aligned_sz = buf_sz;
+
if (!partial_pack_sha1)
continue;