2014-01-08 01:12:40

by Scott Wood

[permalink] [raw]
Subject: Re: [v2] powerpc 8xx: defconfig: slice by 4 is more efficient than the default slice by 8 on Powerpc 8xx.

On Fri, Nov 22, 2013 at 06:28:29PM +0100, LEROY Christophe wrote:
> 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 <[email protected]>
>
>
> diff -ur a/arch/powerpc/configs/adder875_defconfig b/arch/powerpc/configs.new/adder875_defconfig
> --- a/arch/powerpc/configs/adder875_defconfig 2013-11-22 18:20:10.342968268 +0100
> +++ b/arch/powerpc/configs.new/adder875_defconfig 2013-11-22 18:17:46.499686457 +0100
> @@ -70,3 +70,4 @@
> CONFIG_DETECT_HUNG_TASK=y
> CONFIG_DEBUG_INFO=y
> # CONFIG_RCU_CPU_STALL_DETECTOR is not set
> +CONFIG_CRC32_SLICEBY4=y

When applying I got this:
error: arch/powerpc/configs.new/adder875_defconfig: does not exist in index
error: arch/powerpc/configs.new/ep88xc_defconfig: does not exist in index
error: arch/powerpc/configs.new/mpc866_ads_defconfig: does not exist in index
error: arch/powerpc/configs.new/mpc885_ads_defconfig: does not exist in index
error: arch/powerpc/configs.new/tqm8xx_defconfig: does not exist in index

I've fixed it, but please ensure that patches can be applied using "git
am". I recommend using git to generate patches, but if you don't want to
do so be sure that it's the "b" filename, not the "a" filename, that
matches the tree.

-Scott