From e850049bbc831bfe40b87eaea673675d8a829e74 Mon Sep 17 00:00:00 2001 From: Kyungsik Lee Date: Mon, 7 Oct 2013 09:40:35 +0200 Subject: xen: add LZ4 decompression support Add support for LZ4 decompression in Xen. LZ4 Decompression APIs for Xen are based on LZ4 implementation by Yann Collet. Benchmark Results(PATCH v3) Compiler: Linaro ARM gcc 4.6.2 1. ARMv7, 1.5GHz based board Kernel: linux 3.4 Uncompressed Kernel Size: 14MB Compressed Size Decompression Speed LZO 6.7MB 20.1MB/s, 25.2MB/s(UA) LZ4 7.3MB 29.1MB/s, 45.6MB/s(UA) 2. ARMv7, 1.7GHz based board Kernel: linux 3.7 Uncompressed Kernel Size: 14MB Compressed Size Decompression Speed LZO 6.0MB 34.1MB/s, 52.2MB/s(UA) LZ4 6.5MB 86.7MB/s - UA: Unaligned memory Access support - Latest patch set for LZO applied This patch set is for adding support for LZ4-compressed Kernel. LZ4 is a very fast lossless compression algorithm and it also features an extremely fast decoder [1]. But we have five of decompressors already and one question which does arise, however, is that of where do we stop adding new ones? This issue had been discussed and came to the conclusion [2]. Russell King said that we should have: - one decompressor which is the fastest - one decompressor for the highest compression ratio - one popular decompressor (eg conventional gzip) If we have a replacement one for one of these, then it should do exactly that: replace it. The benchmark shows that an 8% increase in image size vs a 66% increase in decompression speed compared to LZO(which has been known as the fastest decompressor in the Kernel). Therefore the "fast but may not be small" compression title has clearly been taken by LZ4 [3]. [1] http://code.google.com/p/lz4/ [2] http://thread.gmane.org/gmane.linux.kbuild.devel/9157 [3] http://thread.gmane.org/gmane.linux.kbuild.devel/9347 LZ4 homepage: http://fastcompression.blogspot.com/p/lz4.html LZ4 source repository: http://code.google.com/p/lz4/ Signed-off-by: Kyungsik Lee Signed-off-by: Yann Collet Signed-off-by: Jan Beulich Acked-by: Keir Fraser --- xen/common/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'xen/common/Makefile') diff --git a/xen/common/Makefile b/xen/common/Makefile index 6da46513e2..fcb4a84e7c 100644 --- a/xen/common/Makefile +++ b/xen/common/Makefile @@ -49,7 +49,7 @@ obj-y += radix-tree.o obj-y += rbtree.o obj-y += lzo.o -obj-bin-$(CONFIG_X86) += $(foreach n,decompress bunzip2 unxz unlzma unlzo earlycpio,$(n).init.o) +obj-bin-$(CONFIG_X86) += $(foreach n,decompress bunzip2 unxz unlzma unlzo unlz4 earlycpio,$(n).init.o) obj-$(perfc) += perfc.o obj-$(crash_debug) += gdbstub.o -- cgit v1.2.3