diff options
| author | Jordan Hargrave <jordan@cvs.openbsd.org> | 2009-08-12 22:01:16 +0000 |
|---|---|---|
| committer | Jordan Hargrave <jordan@cvs.openbsd.org> | 2009-08-12 22:01:16 +0000 |
| commit | e46299ca186e4d1e5303e9ebb8670304dae19897 (patch) | |
| tree | 5eecf9ec208bcc0491473a5cb891d34bacf59bc4 /sys | |
| parent | 5d4bbcf644a8fab8f23f80ff07e893bb4965781e (diff) | |
Optimize Syndrome calculation, 30% speedup on writes
ok marco@
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/dev/softraid_raid6.c | 21 |
1 files changed, 7 insertions, 14 deletions
diff --git a/sys/dev/softraid_raid6.c b/sys/dev/softraid_raid6.c index 657c5725724..0b8a3146e5c 100644 --- a/sys/dev/softraid_raid6.c +++ b/sys/dev/softraid_raid6.c @@ -1,4 +1,4 @@ -/* $OpenBSD: softraid_raid6.c,v 1.4 2009/08/09 14:12:25 marco Exp $ */ +/* $OpenBSD: softraid_raid6.c,v 1.5 2009/08/12 22:01:15 jordan Exp $ */ /* * Copyright (c) 2009 Marco Peereboom <marco@peereboom.us> * Copyright (c) 2009 Jordan Hargrave <jordan@openbsd.org> @@ -44,7 +44,8 @@ #include <dev/softraidvar.h> #include <dev/rndvar.h> -uint8_t gf_pow[512], gf_log[256]; +uint8_t gf_pow[768]; +int gf_log[256]; /* RAID 6 functions. */ int sr_raid6_alloc_resources(struct sr_discipline *); @@ -68,7 +69,6 @@ void *sr_get_block(struct sr_discipline *, int); void sr_put_block(struct sr_discipline *, void *); void gf_init(void); -uint8_t gf_mul(uint8_t, uint8_t); uint8_t gf_inv(uint8_t); #define SR_NOFAIL 0x00 @@ -983,10 +983,12 @@ void sr_raid6_xorq(void *q, void *d, int len, int gn) { uint8_t *qbuf = q, *data = d; + uint8_t *gn_pow = gf_pow + gf_log[gn]; /* Have to do this a byte at a time */ + /* Faster multiply.. gn is always constant */ while (len--) - qbuf[len] ^= gf_mul(data[len], gn); + qbuf[len] ^= gn_pow[gf_log[data[len]]]; } /* Create GF256 log/pow tables: polynomial = 0x11D */ @@ -1002,16 +1004,7 @@ gf_init(void) gf_pow[i] = gf_pow[i+255] = p; p = ((p << 1) ^ ((p & 0x80) ? 0x1D : 0x00)); } -} - -/* GF256 multiplication using exponent/logarithm table */ -uint8_t -gf_mul(uint8_t a, uint8_t b) -{ - /* g^a * g^b = g^(a+b) */ - if (!a || !b) - return (0); - return gf_pow[gf_log[a] + gf_log[b]]; + gf_log[0] = 512; } uint8_t |