--- a/archival/libarchive/open_transformer.c
+++ b/archival/libarchive/open_transformer.c
@@ -213,6 +213,22 @@ void* FAST_FUNC xmalloc_open_zipped_read_close(const char
*fname, size_t *maxsz_
int fd;
char *image;
+ /* Fast path for well-behaved gzip files, avoiding forks. */
+ if (ENABLE_FEATURE_SEAMLESS_GZ && ENABLE_DESKTOP && BB_MMU) {
+ uint16_t magic;
+ fd = open(fname, O_RDONLY);
+ xread(fd, &magic, 2);
+
are you sure that open will succeed at this place ?
re.
wh
Am 27.11.2014 15:27, schrieb Lauri Kasanen:
> Hi,
>
> The performance and number of processes for a "depmod -a" with gzipped
> modules was abysmal. This patch adds a fast path without fork for well-
> behaved gzip files, 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. And of
> course
> a whole lot less processes -> much saved RAM.
>
> function old new delta
> inflate_get_next_window - 1877 +1877
> xmalloc_unpack_gz - 356 +356
> check_header_gzip - 298 +298
> xmalloc_inflate_unzip_internal - 223 +223
> inflate_init - 97 +97
> xmalloc_open_zipped_read_close 73 159 +86
> inflate_store_unused - 35 +35
> unpack_gz_stream 567 299 -268
> inflate_unzip_internal 2304 172 -2132
> ------------------------------------------------------------------------------
> (add/remove: 6/0 grow/shrink: 1/2 up/down: 2972/-2400) Total: 572
> bytes
>
> --
>
> It's currently guarded by CONFIG_DESKTOP. If you'd like a new config
> option instead, please say so.
>
> - Lauri
>
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