Messages in this thread Patch in this message | | | Subject | RE: [patch v3 7/7] crc32: final-cleanup.diff | From | Joakim Tjernlund <> | Date | Wed, 10 Aug 2011 17:48:43 +0200 |
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"Bob Pearson" <rpearson@systemfabricworks.com> wrote on 2011/08/10 17:13:00:
> From: "Bob Pearson" <rpearson@systemfabricworks.com> > To: "'Joakim Tjernlund'" <joakim.tjernlund@transmode.se> > Cc: <akpm@linux-foundation.org>, <fzago@systemfabricworks.com>, "'George Spelvin'" <linux@horizon.com>, <linux-kernel@vger.kernel.org> > Date: 2011/08/10 17:13 > Subject: RE: [patch v3 7/7] crc32: final-cleanup.diff > > OK. Can you post your current version of crc32.c? I'll try to merge them > together.
OK, here it comes again, prefably this should be the first patch in the series.
From f5268d74f1a81610820e92785397f1247946ce15 Mon Sep 17 00:00:00 2001 From: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> Date: Fri, 5 Aug 2011 17:49:42 +0200 Subject: [PATCH] crc32: Optimize inner loop.
taking a pointer reference to each row in the crc table matrix, one can reduce the inner loop with a few insn's on RISC archs like PowerPC. --- lib/crc32.c | 21 +++++++++++---------- 1 files changed, 11 insertions(+), 10 deletions(-)
diff --git a/lib/crc32.c b/lib/crc32.c index 4855995..b06d1e7 100644 --- a/lib/crc32.c +++ b/lib/crc32.c @@ -51,20 +51,21 @@ static inline u32 crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 (*tab)[256]) { # ifdef __LITTLE_ENDIAN -# define DO_CRC(x) crc = tab[0][(crc ^ (x)) & 255] ^ (crc >> 8) -# define DO_CRC4 crc = tab[3][(crc) & 255] ^ \ - tab[2][(crc >> 8) & 255] ^ \ - tab[1][(crc >> 16) & 255] ^ \ - tab[0][(crc >> 24) & 255] +# define DO_CRC(x) crc = t0[(crc ^ (x)) & 255] ^ (crc >> 8) +# define DO_CRC4 crc = t3[(crc) & 255] ^ \ + t2[(crc >> 8) & 255] ^ \ + t1[(crc >> 16) & 255] ^ \ + t0[(crc >> 24) & 255] # else -# define DO_CRC(x) crc = tab[0][((crc >> 24) ^ (x)) & 255] ^ (crc << 8) -# define DO_CRC4 crc = tab[0][(crc) & 255] ^ \ - tab[1][(crc >> 8) & 255] ^ \ - tab[2][(crc >> 16) & 255] ^ \ - tab[3][(crc >> 24) & 255] +# define DO_CRC(x) crc = t0[((crc >> 24) ^ (x)) & 255] ^ (crc << 8) +# define DO_CRC4 crc = t0[(crc) & 255] ^ \ + t1[(crc >> 8) & 255] ^ \ + t2[(crc >> 16) & 255] ^ \ + t3[(crc >> 24) & 255] # endif const u32 *b; size_t rem_len; + const u32 *t0=tab[0], *t1=tab[1], *t2=tab[2], *t3=tab[3];
/* Align it */ if (unlikely((long)buf & 3 && len)) { -- 1.7.3.4
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