From 751ba79cc552c146595cd439b21c4ff8998c3b69 Mon Sep 17 00:00:00 2001 From: Matt Brown Date: Fri, 4 Aug 2017 13:42:32 +1000 Subject: [PATCH] lib/raid6/altivec: Add vpermxor implementation for raid6 Q syndrome This patch uses the vpermxor instruction to optimise the raid6 Q syndrome. This instruction was made available with POWER8, ISA version 2.07. It allows for both vperm and vxor instructions to be done in a single instruction. This has been tested for correctness on a ppc64le vm with a basic RAID6 setup containing 5 drives. The performance benchmarks are from the raid6test in the /lib/raid6/test directory. These results are from an IBM Firestone machine with ppc64le architecture. The benchmark results show a 35% speed increase over the best existing algorithm for powerpc (altivec). The raid6test has also been run on a big-endian ppc64 vm to ensure it also works for big-endian architectures. Performance benchmarks: raid6: altivecx4 gen() 18773 MB/s raid6: altivecx8 gen() 19438 MB/s raid6: vpermxor4 gen() 25112 MB/s raid6: vpermxor8 gen() 26279 MB/s Signed-off-by: Matt Brown Reviewed-by: Daniel Axtens [mpe: Add VPERMXOR macro so we can build with old binutils] Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/ppc-opcode.h | 6 ++ include/linux/raid/pq.h | 4 + lib/raid6/.gitignore | 1 + lib/raid6/Makefile | 27 ++++++- lib/raid6/algos.c | 4 + lib/raid6/test/Makefile | 17 ++++- lib/raid6/vpermxor.uc | 105 ++++++++++++++++++++++++++ 7 files changed, 161 insertions(+), 3 deletions(-) create mode 100644 lib/raid6/vpermxor.uc diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h index f1083bcf449c..7370da18035e 100644 --- a/arch/powerpc/include/asm/ppc-opcode.h +++ b/arch/powerpc/include/asm/ppc-opcode.h @@ -271,6 +271,7 @@ #define PPC_INST_TLBSRX_DOT 0x7c0006a5 #define PPC_INST_VPMSUMW 0x10000488 #define PPC_INST_VPMSUMD 0x100004c8 +#define PPC_INST_VPERMXOR 0x1000002d #define PPC_INST_XXLOR 0xf0000490 #define PPC_INST_XXSWAPD 0xf0000250 #define PPC_INST_XVCPSGNDP 0xf0000780 @@ -517,6 +518,11 @@ #define XVCPSGNDP(t, a, b) stringify_in_c(.long (PPC_INST_XVCPSGNDP | \ VSX_XX3((t), (a), (b)))) +#define VPERMXOR(vrt, vra, vrb, vrc) \ + stringify_in_c(.long (PPC_INST_VPERMXOR | \ + ___PPC_RT(vrt) | ___PPC_RA(vra) | \ + ___PPC_RB(vrb) | (((vrc) & 0x1f) << 6))) + #define PPC_NAP stringify_in_c(.long PPC_INST_NAP) #define PPC_SLEEP stringify_in_c(.long PPC_INST_SLEEP) #define PPC_WINKLE stringify_in_c(.long PPC_INST_WINKLE) diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h index 583cdd3d49ca..fd2e02461e41 100644 --- a/include/linux/raid/pq.h +++ b/include/linux/raid/pq.h @@ -107,6 +107,10 @@ extern const struct raid6_calls raid6_avx512x2; extern const struct raid6_calls raid6_avx512x4; extern const struct raid6_calls raid6_tilegx8; extern const struct raid6_calls raid6_s390vx8; +extern const struct raid6_calls raid6_vpermxor1; +extern const struct raid6_calls raid6_vpermxor2; +extern const struct raid6_calls raid6_vpermxor4; +extern const struct raid6_calls raid6_vpermxor8; struct raid6_recov_calls { void (*data2)(int, size_t, int, int, void **); diff --git a/lib/raid6/.gitignore b/lib/raid6/.gitignore index f01b1cb04f91..3de0d8921286 100644 --- a/lib/raid6/.gitignore +++ b/lib/raid6/.gitignore @@ -4,3 +4,4 @@ int*.c tables.c neon?.c s390vx?.c +vpermxor*.c diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile index 4add700ddfe3..21f59443e99e 100644 --- a/lib/raid6/Makefile +++ b/lib/raid6/Makefile @@ -5,7 +5,8 @@ raid6_pq-y += algos.o recov.o tables.o int1.o int2.o int4.o \ int8.o int16.o int32.o raid6_pq-$(CONFIG_X86) += recov_ssse3.o recov_avx2.o mmx.o sse1.o sse2.o avx2.o avx512.o recov_avx512.o -raid6_pq-$(CONFIG_ALTIVEC) += altivec1.o altivec2.o altivec4.o altivec8.o +raid6_pq-$(CONFIG_ALTIVEC) += altivec1.o altivec2.o altivec4.o altivec8.o \ + vpermxor1.o vpermxor2.o vpermxor4.o vpermxor8.o raid6_pq-$(CONFIG_KERNEL_MODE_NEON) += neon.o neon1.o neon2.o neon4.o neon8.o recov_neon.o recov_neon_inner.o raid6_pq-$(CONFIG_TILEGX) += tilegx8.o raid6_pq-$(CONFIG_S390) += s390vx8.o recov_s390xc.o @@ -91,6 +92,30 @@ $(obj)/altivec8.c: UNROLL := 8 $(obj)/altivec8.c: $(src)/altivec.uc $(src)/unroll.awk FORCE $(call if_changed,unroll) +CFLAGS_vpermxor1.o += $(altivec_flags) +targets += vpermxor1.c +$(obj)/vpermxor1.c: UNROLL := 1 +$(obj)/vpermxor1.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE + $(call if_changed,unroll) + +CFLAGS_vpermxor2.o += $(altivec_flags) +targets += vpermxor2.c +$(obj)/vpermxor2.c: UNROLL := 2 +$(obj)/vpermxor2.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE + $(call if_changed,unroll) + +CFLAGS_vpermxor4.o += $(altivec_flags) +targets += vpermxor4.c +$(obj)/vpermxor4.c: UNROLL := 4 +$(obj)/vpermxor4.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE + $(call if_changed,unroll) + +CFLAGS_vpermxor8.o += $(altivec_flags) +targets += vpermxor8.c +$(obj)/vpermxor8.c: UNROLL := 8 +$(obj)/vpermxor8.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE + $(call if_changed,unroll) + CFLAGS_neon1.o += $(NEON_FLAGS) targets += neon1.c $(obj)/neon1.c: UNROLL := 1 diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c index 476994723258..b2e681018145 100644 --- a/lib/raid6/algos.c +++ b/lib/raid6/algos.c @@ -74,6 +74,10 @@ const struct raid6_calls * const raid6_algos[] = { &raid6_altivec2, &raid6_altivec4, &raid6_altivec8, + &raid6_vpermxor1, + &raid6_vpermxor2, + &raid6_vpermxor4, + &raid6_vpermxor8, #endif #if defined(CONFIG_TILEGX) &raid6_tilegx8, diff --git a/lib/raid6/test/Makefile b/lib/raid6/test/Makefile index be1010bdc435..ef6d0e00f189 100644 --- a/lib/raid6/test/Makefile +++ b/lib/raid6/test/Makefile @@ -48,7 +48,8 @@ else gcc -c -x c - >&/dev/null && \ rm ./-.o && echo yes) ifeq ($(HAS_ALTIVEC),yes) - OBJS += altivec1.o altivec2.o altivec4.o altivec8.o + OBJS += altivec1.o altivec2.o altivec4.o altivec8.o \ + vpermxor1.o vpermxor2.o vpermxor4.o vpermxor8.o endif endif ifeq ($(ARCH),tilegx) @@ -98,6 +99,18 @@ altivec4.c: altivec.uc ../unroll.awk altivec8.c: altivec.uc ../unroll.awk $(AWK) ../unroll.awk -vN=8 < altivec.uc > $@ +vpermxor1.c: vpermxor.uc ../unroll.awk + $(AWK) ../unroll.awk -vN=1 < vpermxor.uc > $@ + +vpermxor2.c: vpermxor.uc ../unroll.awk + $(AWK) ../unroll.awk -vN=2 < vpermxor.uc > $@ + +vpermxor4.c: vpermxor.uc ../unroll.awk + $(AWK) ../unroll.awk -vN=4 < vpermxor.uc > $@ + +vpermxor8.c: vpermxor.uc ../unroll.awk + $(AWK) ../unroll.awk -vN=8 < vpermxor.uc > $@ + int1.c: int.uc ../unroll.awk $(AWK) ../unroll.awk -vN=1 < int.uc > $@ @@ -123,7 +136,7 @@ tables.c: mktables ./mktables > tables.c clean: - rm -f *.o *.a mktables mktables.c *.uc int*.c altivec*.c neon*.c tables.c raid6test + rm -f *.o *.a mktables mktables.c *.uc int*.c altivec*.c vpermxor*.c neon*.c tables.c raid6test rm -f tilegx*.c spotless: clean diff --git a/lib/raid6/vpermxor.uc b/lib/raid6/vpermxor.uc new file mode 100644 index 000000000000..10475dc423c1 --- /dev/null +++ b/lib/raid6/vpermxor.uc @@ -0,0 +1,105 @@ +/* + * Copyright 2017, Matt Brown, IBM Corp. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * vpermxor$#.c + * + * Based on H. Peter Anvin's paper - The mathematics of RAID-6 + * + * $#-way unrolled portable integer math RAID-6 instruction set + * This file is postprocessed using unroll.awk + * + * vpermxor$#.c makes use of the vpermxor instruction to optimise the RAID6 Q + * syndrome calculations. + * This can be run on systems which have both Altivec and vpermxor instruction. + * + * This instruction was introduced in POWER8 - ISA v2.07. + */ + +#include +#ifdef CONFIG_ALTIVEC + +#include +#ifdef __KERNEL__ +#include +#include +#include +#endif + +typedef vector unsigned char unative_t; +#define NSIZE sizeof(unative_t) + +static const vector unsigned char gf_low = {0x1e, 0x1c, 0x1a, 0x18, 0x16, 0x14, + 0x12, 0x10, 0x0e, 0x0c, 0x0a, 0x08, + 0x06, 0x04, 0x02,0x00}; +static const vector unsigned char gf_high = {0xfd, 0xdd, 0xbd, 0x9d, 0x7d, 0x5d, + 0x3d, 0x1d, 0xe0, 0xc0, 0xa0, 0x80, + 0x60, 0x40, 0x20, 0x00}; + +static void noinline raid6_vpermxor$#_gen_syndrome_real(int disks, size_t bytes, + void **ptrs) +{ + u8 **dptr = (u8 **)ptrs; + u8 *p, *q; + int d, z, z0; + unative_t wp$$, wq$$, wd$$; + + z0 = disks - 3; /* Highest data disk */ + p = dptr[z0+1]; /* XOR parity */ + q = dptr[z0+2]; /* RS syndrome */ + + for (d = 0; d < bytes; d += NSIZE*$#) { + wp$$ = wq$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE]; + + for (z = z0-1; z>=0; z--) { + wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE]; + /* P syndrome */ + wp$$ = vec_xor(wp$$, wd$$); + + /* Q syndrome */ + asm(VPERMXOR(%0,%1,%2,%3):"=v"(wq$$):"v"(gf_high), "v"(gf_low), "v"(wq$$)); + wq$$ = vec_xor(wq$$, wd$$); + } + *(unative_t *)&p[d+NSIZE*$$] = wp$$; + *(unative_t *)&q[d+NSIZE*$$] = wq$$; + } +} + +static void raid6_vpermxor$#_gen_syndrome(int disks, size_t bytes, void **ptrs) +{ + preempt_disable(); + enable_kernel_altivec(); + + raid6_vpermxor$#_gen_syndrome_real(disks, bytes, ptrs); + + disable_kernel_altivec(); + preempt_enable(); +} + +int raid6_have_altivec_vpermxor(void); +#if $# == 1 +int raid6_have_altivec_vpermxor(void) +{ + /* Check if arch has both altivec and the vpermxor instructions */ +# ifdef __KERNEL__ + return (cpu_has_feature(CPU_FTR_ALTIVEC_COMP) && + cpu_has_feature(CPU_FTR_ARCH_207S)); +# else + return 1; +#endif + +} +#endif + +const struct raid6_calls raid6_vpermxor$# = { + raid6_vpermxor$#_gen_syndrome, + NULL, + raid6_have_altivec_vpermxor, + "vpermxor$#", + 0 +}; +#endif