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ae77cbc1e7
This change adds TILE-Gx SIMD instructions to the software raid (md), modeling the Altivec implementation. This is only for Syndrome generation; there is more that could be done to improve recovery, as in the recent Intel SSE3 recovery implementation. The code unrolls 8 times; this turns out to be the best on tilegx hardware among the set 1, 2, 4, 8 or 16. The code reads one cache-line of data from each disk, stores P and Q then goes to the next cache-line. The test code in sys/linux/lib/raid6/test reports 2008 MB/s data read rate for syndrome generation using 18 disks (16 data and 2 parity). It was 1512 MB/s before this SIMD optimizations. This is running on 1 core with all the data in cache. This is based on the paper The Mathematics of RAID-6. (http://kernel.org/pub/linux/kernel/people/hpa/raid6.pdf). Signed-off-by: Ken Steele <ken@tilera.com> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: NeilBrown <neilb@suse.de>
87 lines
2.1 KiB
Ucode
87 lines
2.1 KiB
Ucode
/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright 2002 H. Peter Anvin - All Rights Reserved
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* Copyright 2012 Tilera Corporation - All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
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* Boston MA 02111-1307, USA; either version 2 of the License, or
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* (at your option) any later version; incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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/*
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* tilegx$#.c
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*
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* $#-way unrolled TILE-Gx SIMD for RAID-6 math.
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*
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* This file is postprocessed using unroll.awk.
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*
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*/
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#include <linux/raid/pq.h>
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/* Create 8 byte copies of constant byte */
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# define NBYTES(x) (__insn_v1addi(0, x))
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# define NSIZE 8
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/*
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* The SHLBYTE() operation shifts each byte left by 1, *not*
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* rolling over into the next byte
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*/
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static inline __attribute_const__ u64 SHLBYTE(u64 v)
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{
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/* Vector One Byte Shift Left Immediate. */
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return __insn_v1shli(v, 1);
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}
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/*
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* The MASK() operation returns 0xFF in any byte for which the high
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* bit is 1, 0x00 for any byte for which the high bit is 0.
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*/
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static inline __attribute_const__ u64 MASK(u64 v)
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{
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/* Vector One Byte Shift Right Signed Immediate. */
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return __insn_v1shrsi(v, 7);
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}
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void raid6_tilegx$#_gen_syndrome(int disks, size_t bytes, void **ptrs)
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{
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u8 **dptr = (u8 **)ptrs;
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u64 *p, *q;
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int d, z, z0;
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u64 wd$$, wq$$, wp$$, w1$$, w2$$;
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u64 x1d = NBYTES(0x1d);
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u64 * z0ptr;
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z0 = disks - 3; /* Highest data disk */
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p = (u64 *)dptr[z0+1]; /* XOR parity */
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q = (u64 *)dptr[z0+2]; /* RS syndrome */
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z0ptr = (u64 *)&dptr[z0][0];
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for ( d = 0 ; d < bytes ; d += NSIZE*$# ) {
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wq$$ = wp$$ = *z0ptr++;
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for ( z = z0-1 ; z >= 0 ; z-- ) {
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wd$$ = *(u64 *)&dptr[z][d+$$*NSIZE];
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wp$$ = wp$$ ^ wd$$;
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w2$$ = MASK(wq$$);
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w1$$ = SHLBYTE(wq$$);
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w2$$ = w2$$ & x1d;
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w1$$ = w1$$ ^ w2$$;
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wq$$ = w1$$ ^ wd$$;
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}
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*p++ = wp$$;
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*q++ = wq$$;
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}
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}
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const struct raid6_calls raid6_tilegx$# = {
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raid6_tilegx$#_gen_syndrome,
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NULL,
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"tilegx$#",
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0
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};
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