Messages in this thread Patch in this message | | | From | Christophe Leroy <> | Subject | [PATCH] lib/crc32: slice by 4 is more efficient than the default slice by 8 on Powerpc 8xx. | Date | Mon, 18 Nov 2013 08:04:23 +0100 (CET) |
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On PPC_8xx, CRC32_SLICEBY4 is more efficient (almost twice) than CRC32_SLICEBY8, as shown below:
With CRC32_SLICEBY8: [ 1.109204] crc32: CRC_LE_BITS = 64, CRC_BE BITS = 64 [ 1.114401] crc32: self tests passed, processed 225944 bytes in 15118910 nsec [ 1.130655] crc32c: CRC_LE_BITS = 64 [ 1.134235] crc32c: self tests passed, processed 225944 bytes in 4479879 nsec
With CRC32_SLICEBY4: [ 1.097129] crc32: CRC_LE_BITS = 32, CRC_BE BITS = 32 [ 1.101878] crc32: self tests passed, processed 225944 bytes in 8616242 nsec [ 1.116298] crc32c: CRC_LE_BITS = 32 [ 1.119607] crc32c: self tests passed, processed 225944 bytes in 3289576 nsec
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Index: a/lib/Kconfig =================================================================== --- a/lib/Kconfig (révision 5325) +++ b/lib/Kconfig (copie de travail) @@ -102,6 +102,7 @@ choice prompt "CRC32 implementation" depends on CRC32 + default CRC32_SLICEBY4 if PPC_8xx default CRC32_SLICEBY8 help This option allows a kernel builder to override the default choice -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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