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| author | Darrick J. Wong <djwong@us.ibm.com> | 2012-03-23 15:02:26 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-23 16:58:38 -0700 |
| commit | 5cde7656d0dd222170eb0250bd1f70c9018fd438 (patch) | |
| tree | 6ebd5b76968f84d5fd8545cfe3400162d76d222c /lib/Kconfig | |
| parent | 577eba9e22e872574c466648b46eeb3e0d04372e (diff) | |
| download | lwn-5cde7656d0dd222170eb0250bd1f70c9018fd438.tar.gz lwn-5cde7656d0dd222170eb0250bd1f70c9018fd438.zip | |
crc32: select an algorithm via Kconfig
Allow the kernel builder to choose a crc32* algorithm for the kernel.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/Kconfig')
| -rw-r--r-- | lib/Kconfig | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/lib/Kconfig b/lib/Kconfig index 6d7ce4b138c4..43359bb1ca90 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -80,6 +80,49 @@ config CRC32_SELFTEST and crc32_be over byte strings with random alignment and length and computes the total elapsed time and number of bytes processed. +choice + prompt "CRC32 implementation" + depends on CRC32 + default CRC32_SLICEBY8 + +config CRC32_SLICEBY8 + bool "Slice by 8 bytes" + help + Calculate checksum 8 bytes at a time with a clever slicing algorithm. + This is the fastest algorithm, but comes with a 8KiB lookup table. + Most modern processors have enough cache to hold this table without + thrashing the cache. + + This is the default implementation choice. Choose this one unless + you have a good reason not to. + +config CRC32_SLICEBY4 + bool "Slice by 4 bytes" + help + Calculate checksum 4 bytes at a time with a clever slicing algorithm. + This is a bit slower than slice by 8, but has a smaller 4KiB lookup + table. + + Only choose this option if you know what you are doing. + +config CRC32_SARWATE + bool "Sarwate's Algorithm (one byte at a time)" + help + Calculate checksum a byte at a time using Sarwate's algorithm. This + is not particularly fast, but has a small 256 byte lookup table. + + Only choose this option if you know what you are doing. + +config CRC32_BIT + bool "Classic Algorithm (one bit at a time)" + help + Calculate checksum one bit at a time. This is VERY slow, but has + no lookup table. This is provided as a debugging option. + + Only choose this option if you are debugging crc32. + +endchoice + config CRC7 tristate "CRC7 functions" help |