On Fri, Jun 06, 2014 at 11:08:58PM -0400, George Spelvin wrote: > There's no need for the K_table to be made of 64-bit words. For some > reason, the original authors didn't fully reduce the values modulo the > CRC32C polynomial, and so had some 33-bit values in there. They can > all be reduced to 32 bits. > > Doing that cuts the table size in half. Since the code depends on both > pclmulq and crc32, SSE 4.1 is obviously present, so we can use pmovzxdq > to fetch it in the correct format. > > This adds (measured on Ivy Bridge) 1 cycle per main loop iteration > (CRC of up to 3K bytes), less than 0.2%. The hope is that the reduced > D-cache footprint will make up the loss in other code. > > Two other related fixes: > * K_table is read-only, so belongs in .rodata, and > * There's no need for more than 8-byte alignment > > Acked-by: Tim Chen <[email protected]> > Signed-off-by: George Spelvin <[email protected]>
Patch applied. Thanks! -- Email: Herbert Xu <[email protected]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
