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4f3865fb57
Upgrade the zlib_inflate implementation in the kernel from a patched version 1.1.3/4 to a patched 1.2.3. The code in the kernel is about seven years old and I noticed that the external zlib library's inflate performance was significantly faster (~50%) than the code in the kernel on ARM (and faster again on x86_32). For comparison the newer deflate code is 20% slower on ARM and 50% slower on x86_32 but gives an approx 1% compression ratio improvement. I don't consider this to be an improvement for kernel use so have no plans to change the zlib_deflate code. Various changes have been made to the zlib code in the kernel, the most significant being the extra functions/flush option used by ppp_deflate. This update reimplements the features PPP needs to ensure it continues to work. This code has been tested on ARM under both JFFS2 (with zlib compression enabled) and ppp_deflate and on x86_32. JFFS2 sees an approx. 10% real world file read speed improvement. This patch also removes ZLIB_VERSION as it no longer has a correct value. We don't need version checks anyway as the kernel's module handling will take care of that for us. This removal is also more in keeping with the zlib author's wishes (http://www.zlib.net/zlib_faq.html#faq24) and I've added something to the zlib.h header to note its a modified version. Signed-off-by: Richard Purdie <rpurdie@rpsys.net> Acked-by: Joern Engel <joern@wh.fh-wedel.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
20 lines
549 B
Makefile
20 lines
549 B
Makefile
#
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# This is a modified version of zlib, which does all memory
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# allocation ahead of time.
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#
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# This is only the decompression, see zlib_deflate for the
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# the compression
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#
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# Decompression needs to be serialized for each memory
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# allocation.
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#
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# (The upsides of the simplification is that you can't get in
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# any nasty situations wrt memory management, and that the
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# uncompression can be done without blocking on allocation).
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#
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obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate.o
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zlib_inflate-objs := inffast.o inflate.o \
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inftrees.o inflate_syms.o
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