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

[Christophe Leroy]

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 <christop...@c-s.fr>

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
diff -ur a/arch/powerpc/configs/ep88xc_defconfig b/arch/powerpc/configs.new/ep88xc_defconfig
--- a/arch/powerpc/configs/ep88xc_defconfig 2013-11-22 18:20:10.286961148 +0100
+++ b/arch/powerpc/configs.new/ep88xc_defconfig 2013-11-22 18:17:41.992113565 +0100
@@ -72,3 +72,4 @@
CONFIG_DETECT_HUNG_TASK=y
CONFIG_DEBUG_INFO=y
# CONFIG_RCU_CPU_STALL_DETECTOR is not set
+CONFIG_CRC32_SLICEBY4=y
diff -ur a/arch/powerpc/configs/mpc866_ads_defconfig b/arch/powerpc/configs.new/mpc866_ads_defconfig
--- a/arch/powerpc/configs/mpc866_ads_defconfig 2013-11-22 18:20:10.323965853 +0100
+++ b/arch/powerpc/configs.new/mpc866_ads_defconfig 2013-11-22 18:17:32.480904735 +0100
@@ -55,3 +55,4 @@
CONFIG_CRC_CCITT=y
# CONFIG_RCU_CPU_STALL_DETECTOR is not set
# CONFIG_CRYPTO_ANSI_CPRNG is not set
+CONFIG_CRC32_SLICEBY4=y
diff -ur a/arch/powerpc/configs/mpc885_ads_defconfig b/arch/powerpc/configs.new/mpc885_ads_defconfig
--- a/arch/powerpc/configs/mpc885_ads_defconfig 2013-11-22 18:20:10.326966235 +0100
+++ b/arch/powerpc/configs.new/mpc885_ads_defconfig 2013-11-22 18:17:25.760050546 +0100
@@ -78,3 +78,4 @@
CONFIG_DETECT_HUNG_TASK=y
CONFIG_DEBUG_INFO=y
# CONFIG_RCU_CPU_STALL_DETECTOR is not set
+CONFIG_CRC32_SLICEBY4=y
diff -ur a/arch/powerpc/configs/tqm8xx_defconfig b/arch/powerpc/configs.new/tqm8xx_defconfig
--- a/arch/powerpc/configs/tqm8xx_defconfig 2013-11-22 18:20:10.317965090 +0100
+++ b/arch/powerpc/configs.new/tqm8xx_defconfig 2013-11-22 18:17:14.926673681 +0100
@@ -84,3 +84,4 @@
CONFIG_DETECT_HUNG_TASK=y
CONFIG_DEBUG_INFO=y
# CONFIG_RCU_CPU_STALL_DETECTOR is not set
+CONFIG_CRC32_SLICEBY4=y
--
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[Scott Wood]

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 <christop...@c-s.fr>
>
>
> 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