mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-27 14:43:58 +08:00
751ba79cc5
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 <matthew.brown.dev@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> [mpe: Add VPERMXOR macro so we can build with old binutils] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
106 lines
2.7 KiB
Ucode
106 lines
2.7 KiB
Ucode
/*
|
|
* 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 <linux/raid/pq.h>
|
|
#ifdef CONFIG_ALTIVEC
|
|
|
|
#include <altivec.h>
|
|
#ifdef __KERNEL__
|
|
#include <asm/cputable.h>
|
|
#include <asm/ppc-opcode.h>
|
|
#include <asm/switch_to.h>
|
|
#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
|