{"push_id":1351166863,"size":1,"distinct_size":1,"ref":"refs/heads/mm","head":"f055e409eb6ba6361b35442e87cc291f381be065","before":"61462e9a6decf3409248ba0baf0b925c17cdf07e","commits":[{"sha":"f055e409eb6ba6361b35442e87cc291f381be065","author":{"name":"Kyungsik Lee","email":"fffc40064e243672081195c46f3af080981457bc@lge.com"},"message":"decompressor: add LZ4 decompressor module\n\nAdd support for LZ4 decompression in the Linux Kernel.  LZ4 Decompression\nAPIs for kernel are based on LZ4 implementation by Yann Collet.\n\nBenchmark Results(PATCH v3)\nCompiler: Linaro ARM gcc 4.6.2\n\n1. ARMv7, 1.5GHz based board\n   Kernel: linux 3.4\n   Uncompressed Kernel Size: 14MB\n        Compressed Size  Decompression Speed\n   LZO  6.7MB            20.1MB/s, 25.2MB/s(UA)\n   LZ4  7.3MB            29.1MB/s, 45.6MB/s(UA)\n\n2. ARMv7, 1.7GHz based board\n   Kernel: linux 3.7\n   Uncompressed Kernel Size: 14MB\n        Compressed Size  Decompression Speed\n   LZO  6.0MB            34.1MB/s, 52.2MB/s(UA)\n   LZ4  6.5MB            86.7MB/s\n- UA: Unaligned memory Access support\n- Latest patch set for LZO applied\n\nThis patch set is for adding support for LZ4-compressed Kernel.  LZ4 is a\nvery fast lossless compression algorithm and it also features an extremely\nfast decoder [1].\n\nBut we have five of decompressors already and one question which does\narise, however, is that of where do we stop adding new ones?  This issue\nhad been discussed and came to the conclusion [2].\n\nRussell King said that we should have:\n\n - one decompressor which is the fastest\n - one decompressor for the highest compression ratio\n - one popular decompressor (eg conventional gzip)\n\nIf we have a replacement one for one of these, then it should do exactly\nthat: replace it.\n\nThe benchmark shows that an 8% increase in image size vs a 66% increase\nin decompression speed compared to LZO(which has been known as the\nfastest decompressor in the Kernel).  Therefore the \"fast but may not be\nsmall\" compression title has clearly been taken by LZ4 [3].\n\n[1] http://code.google.com/p/lz4/\n[2] http://thread.gmane.org/gmane.linux.kbuild.devel/9157\n[3] http://thread.gmane.org/gmane.linux.kbuild.devel/9347\n\nLZ4 homepage: http://fastcompression.blogspot.com/p/lz4.html\nLZ4 source repository: http://code.google.com/p/lz4/\n\nSigned-off-by: Kyungsik Lee <kyungsik.lee@lge.com>\nSigned-off-by: Yann Collet <yann.collet.73@gmail.com>\nCc: \"H. Peter Anvin\" <hpa@zytor.com>\nCc: Ingo Molnar <mingo@elte.hu>\nCc: Thomas Gleixner <tglx@linutronix.de>\nCc: Russell King <rmk@arm.linux.org.uk>\nCc: Borislav Petkov <bp@alien8.de>\nCc: Florian Fainelli <florian@openwrt.org>\nSigned-off-by: Andrew Morton <akpm@linux-foundation.org>\nSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>\nChange-Id: I1cf752fa48886aeff3c8732e3413f53c82b30e56\nReviewed-on: http://gerrit.mot.com/694981\nSubmit-Approved: Jira Key <jirakey@motorola.com>\nTested-by: Jira Key <jirakey@motorola.com>\nReviewed-by: Jeffrey Carlyle <jeff.carlyle@motorola.com>\nSLTApproved: Christopher Fries <cfries@motorola.com>\n(cherry picked from commit b94a1d3f57d659195911077b087a9f7661492812)\n\nConflicts:\n\tinclude/linux/lz4.h\n\tlib/lz4/lz4_decompress.c\n\tlib/lz4/lz4defs.h","distinct":true,"url":"https://api.github.com/repos/travarilo/redkancut_kernel/commits/f055e409eb6ba6361b35442e87cc291f381be065"}]}
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