[PATCH] powerpc: Add VMX optimised xor for RAID5
Benjamin Herrenschmidt
benh at kernel.crashing.org
Fri Oct 11 16:53:58 EST 2013
On Thu, 2013-09-26 at 13:30 +1000, Anton Blanchard wrote:
> Add a VMX optimised xor, used primarily for RAID5. On a POWER7 blade
> this is a decent win:
>
> 32regs : 17932.800 MB/sec
> altivec : 19724.800 MB/sec
>
> The bigger gain is when the same test is run in SMT4 mode, as it
> would if the machine was busy:
>
> 8regs : 8377.600 MB/sec
> altivec : 15801.600 MB/sec
>
> I tested this against an array created without the patch, and also
> verified it worked as expected on a little endian kernel.
>
> Signed-off-by: Anton Blanchard <anton at samba.org>
> ---
Patch got busticated on the way to the list ...
> Index: le-kernel/arch/powerpc/include/asm/xor.h
> ===================================================================
> --- le-kernel.orig/arch/powerpc/include/asm/xor.h
> +++ le-kernel/arch/powerpc/include/asm/xor.h
> @@ -1 +1,68 @@
> +/*
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
> 02111-1307, USA.
> + *
> + * Copyright (C) IBM Corporation, 2012
> + *
> + * Author: Anton Blanchard <anton at au.ibm.com>
> + */
> +#ifndef _ASM_POWERPC_XOR_H
> +#define _ASM_POWERPC_XOR_H
> +
> +#ifdef CONFIG_ALTIVEC
> +
> +#include <asm/cputable.h>
> +
> +void xor_altivec_2(unsigned long bytes, unsigned long *v1_in,
> + unsigned long *v2_in);
> +void xor_altivec_3(unsigned long bytes, unsigned long *v1_in,
> + unsigned long *v2_in, unsigned long *v3_in);
> +void xor_altivec_4(unsigned long bytes, unsigned long *v1_in,
> + unsigned long *v2_in, unsigned long *v3_in,
> + unsigned long *v4_in);
> +void xor_altivec_5(unsigned long bytes, unsigned long *v1_in,
> + unsigned long *v2_in, unsigned long *v3_in,
> + unsigned long *v4_in, unsigned long *v5_in);
> +
> +static struct xor_block_template xor_block_altivec = {
> + .name = "altivec",
> + .do_2 = xor_altivec_2,
> + .do_3 = xor_altivec_3,
> + .do_4 = xor_altivec_4,
> + .do_5 = xor_altivec_5,
> +};
> +
> +#define XOR_SPEED_ALTIVEC() \
> + do { \
> + if (cpu_has_feature(CPU_FTR_ALTIVEC)) \
> + xor_speed(&xor_block_altivec); \
> + } while (0)
> +#else
> +#define XOR_SPEED_ALTIVEC
> +#endif
> +
> +/* Also try the generic routines. */
> #include <asm-generic/xor.h>
> +
> +#undef XOR_TRY_TEMPLATES
> +#define XOR_TRY_TEMPLATES \
> +do { \
> + xor_speed(&xor_block_8regs); \
> + xor_speed(&xor_block_8regs_p); \
> + xor_speed(&xor_block_32regs); \
> + xor_speed(&xor_block_32regs_p); \
> + XOR_SPEED_ALTIVEC(); \
> +} while (0)
> +
> +#endif /* _ASM_POWERPC_XOR_H */
> Index: le-kernel/arch/powerpc/lib/Makefile
> ===================================================================
> --- le-kernel.orig/arch/powerpc/lib/Makefile
> +++ le-kernel/arch/powerpc/lib/Makefile
> @@ -39,3 +39,6 @@ obj-$(CONFIG_PPC_LIB_RHEAP) += rheap.o
> obj-y += code-patching.o
> obj-y += feature-fixups.o
> obj-$(CONFIG_FTR_FIXUP_SELFTEST) += feature-fixups-test.o
> +
> +obj-$(CONFIG_ALTIVEC) += xor_vmx.o
> +CFLAGS_xor_vmx.o += -maltivec -mabi=altivec
> Index: le-kernel/arch/powerpc/lib/xor_vmx.c
> ===================================================================
> --- /dev/null
> +++ le-kernel/arch/powerpc/lib/xor_vmx.c
> @@ -0,0 +1,177 @@
> +/*
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
> 02111-1307, USA.
> + *
> + * Copyright (C) IBM Corporation, 2012
> + *
> + * Author: Anton Blanchard <anton at au.ibm.com>
> + */
> +#include <altivec.h>
> +
> +#include <linux/preempt.h>
> +#include <linux/export.h>
> +#include <linux/sched.h>
> +#include <asm/switch_to.h>
> +
> +typedef vector signed char unative_t;
> +
> +#define DEFINE(V) \
> + unative_t *V = (unative_t *)V##_in; \
> + unative_t V##_0, V##_1, V##_2, V##_3
> +
> +#define LOAD(V) \
> + do { \
> + V##_0 = V[0]; \
> + V##_1 = V[1]; \
> + V##_2 = V[2]; \
> + V##_3 = V[3]; \
> + } while (0)
> +
> +#define STORE(V) \
> + do { \
> + V[0] = V##_0; \
> + V[1] = V##_1; \
> + V[2] = V##_2; \
> + V[3] = V##_3; \
> + } while (0)
> +
> +#define XOR(V1, V2) \
> + do { \
> + V1##_0 = vec_xor(V1##_0, V2##_0); \
> + V1##_1 = vec_xor(V1##_1, V2##_1); \
> + V1##_2 = vec_xor(V1##_2, V2##_2); \
> + V1##_3 = vec_xor(V1##_3, V2##_3); \
> + } while (0)
> +
> +void xor_altivec_2(unsigned long bytes, unsigned long *v1_in,
> + unsigned long *v2_in)
> +{
> + DEFINE(v1);
> + DEFINE(v2);
> + unsigned long lines = bytes / (sizeof(unative_t)) / 4;
> +
> + preempt_disable();
> + enable_kernel_altivec();
> +
> + do {
> + LOAD(v1);
> + LOAD(v2);
> + XOR(v1, v2);
> + STORE(v1);
> +
> + v1 += 4;
> + v2 += 4;
> + } while (--lines > 0);
> +
> + preempt_enable();
> +}
> +EXPORT_SYMBOL(xor_altivec_2);
> +
> +void xor_altivec_3(unsigned long bytes, unsigned long *v1_in,
> + unsigned long *v2_in, unsigned long *v3_in)
> +{
> + DEFINE(v1);
> + DEFINE(v2);
> + DEFINE(v3);
> + unsigned long lines = bytes / (sizeof(unative_t)) / 4;
> +
> + preempt_disable();
> + enable_kernel_altivec();
> +
> + do {
> + LOAD(v1);
> + LOAD(v2);
> + LOAD(v3);
> + XOR(v1, v2);
> + XOR(v1, v3);
> + STORE(v1);
> +
> + v1 += 4;
> + v2 += 4;
> + v3 += 4;
> + } while (--lines > 0);
> +
> + preempt_enable();
> +}
> +EXPORT_SYMBOL(xor_altivec_3);
> +
> +void xor_altivec_4(unsigned long bytes, unsigned long *v1_in,
> + unsigned long *v2_in, unsigned long *v3_in,
> + unsigned long *v4_in)
> +{
> + DEFINE(v1);
> + DEFINE(v2);
> + DEFINE(v3);
> + DEFINE(v4);
> + unsigned long lines = bytes / (sizeof(unative_t)) / 4;
> +
> + preempt_disable();
> + enable_kernel_altivec();
> +
> + do {
> + LOAD(v1);
> + LOAD(v2);
> + LOAD(v3);
> + LOAD(v4);
> + XOR(v1, v2);
> + XOR(v3, v4);
> + XOR(v1, v3);
> + STORE(v1);
> +
> + v1 += 4;
> + v2 += 4;
> + v3 += 4;
> + v4 += 4;
> + } while (--lines > 0);
> +
> + preempt_enable();
> +}
> +EXPORT_SYMBOL(xor_altivec_4);
> +
> +void xor_altivec_5(unsigned long bytes, unsigned long *v1_in,
> + unsigned long *v2_in, unsigned long *v3_in,
> + unsigned long *v4_in, unsigned long *v5_in)
> +{
> + DEFINE(v1);
> + DEFINE(v2);
> + DEFINE(v3);
> + DEFINE(v4);
> + DEFINE(v5);
> + unsigned long lines = bytes / (sizeof(unative_t)) / 4;
> +
> + preempt_disable();
> + enable_kernel_altivec();
> +
> + do {
> + LOAD(v1);
> + LOAD(v2);
> + LOAD(v3);
> + LOAD(v4);
> + LOAD(v5);
> + XOR(v1, v2);
> + XOR(v3, v4);
> + XOR(v1, v5);
> + XOR(v1, v3);
> + STORE(v1);
> +
> + v1 += 4;
> + v2 += 4;
> + v3 += 4;
> + v4 += 4;
> + v5 += 4;
> + } while (--lines > 0);
> +
> + preempt_enable();
> +}
> +EXPORT_SYMBOL(xor_altivec_5);
More information about the Linuxppc-dev
mailing list