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libarchive: add capability to unpack to mem.buffer

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The performance and number of processes for a "depmod -a" with gzipped
modules was abysmal. This patch adds a code path without fork,
benefiting all users of xmalloc_open_zipped_read_close.

"modinfo radeon.ko.gz", a single-file reader, got 30% faster.
"depmod -a", which used to fork over 800 times, got 20% faster.

Heavily based on a patch by Lauri Kasanen <curaga@operamail.com>

function                                             old     new   delta
setup_transformer_on_fd                                -     159    +159
transformer_write                                      -     122    +122
fork_transformer                                       -     112    +112
xmalloc_open_zipped_read_close                        63     118     +55
read_bunzip                                         1866    1896     +30
xtransformer_write                                     -      19     +19
unzip_main                                          2449    2462     +13
bbunpack                                             755     766     +11
unpack_lzma_stream                                  2717    2723      +6
unpack_xz_stream                                    2393    2397      +4
unpack_Z_stream                                     1173    1175      +2
inflate_unzip                                        111     105      -6
check_signature16                                     70      63      -7
unpack_bz2_stream                                    359     349     -10
unpack_unxz                                           12       -     -12
unpack_unlzma                                         12       -     -12
unpack_uncompress                                     12       -     -12
unpack_gunzip                                         12       -     -12
unpack_bunzip2                                        12       -     -12
open_transformer                                     106      92     -14
inflate_unzip_internal                              1945    1916     -29
unpack_gz_stream                                     693     655     -38
open_zipped                                           89      47     -42
setup_unzip_on_fd                                    142      53     -89
------------------------------------------------------------------------------
(add/remove: 4/5 grow/shrink: 7/8 up/down: 533/-295)          Total: 238 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2014-12-07 00:44:00 +01:00
parent e7800f351a
commit b4c11c1397
14 changed files with 243 additions and 127 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
archival/libarchive/decompress_uncompress.c
View File

@@ -73,7 +73,7 @@
*/
IF_DESKTOP(long long) int FAST_FUNC
unpack_Z_stream(transformer_state_t *xstate, int src_fd, int dst_fd)
unpack_Z_stream(transformer_state_t *xstate)
{
IF_DESKTOP(long long total_written = 0;)
IF_DESKTOP(long long) int retval = -1;
@@ -102,7 +102,7 @@ unpack_Z_stream(transformer_state_t *xstate, int src_fd, int dst_fd)
/* block compress mode -C compatible with 2.0 */
int block_mode; /* = BLOCK_MODE; */
if (check_signature16(xstate, src_fd, COMPRESS_MAGIC))
if (check_signature16(xstate, COMPRESS_MAGIC))
return -1;
inbuf = xzalloc(IBUFSIZ + 64);
@@ -114,7 +114,7 @@ unpack_Z_stream(transformer_state_t *xstate, int src_fd, int dst_fd)
/* xread isn't good here, we have to return - caller may want
* to do some cleanup (e.g. delete incomplete unpacked file etc) */
if (full_read(src_fd, inbuf, 1) != 1) {
if (full_read(xstate->src_fd, inbuf, 1) != 1) {
bb_error_msg("short read");
goto err;
}
@@ -166,7 +166,7 @@ unpack_Z_stream(transformer_state_t *xstate, int src_fd, int dst_fd)
}
if (insize < (int) (IBUFSIZ + 64) - IBUFSIZ) {
rsize = safe_read(src_fd, inbuf + insize, IBUFSIZ);
rsize = safe_read(xstate->src_fd, inbuf + insize, IBUFSIZ);
if (rsize < 0)
bb_error_msg_and_die(bb_msg_read_error);
insize += rsize;
@@ -274,7 +274,7 @@ unpack_Z_stream(transformer_state_t *xstate, int src_fd, int dst_fd)
}
if (outpos >= OBUFSIZ) {
xwrite(dst_fd, outbuf, outpos);
xtransformer_write(xstate, outbuf, outpos);
IF_DESKTOP(total_written += outpos;)
outpos = 0;
}
@@ -301,7 +301,7 @@ unpack_Z_stream(transformer_state_t *xstate, int src_fd, int dst_fd)
} while (rsize > 0);
if (outpos > 0) {
xwrite(dst_fd, outbuf, outpos);
xtransformer_write(xstate, outbuf, outpos);
IF_DESKTOP(total_written += outpos;)
}