Messages in this thread | | | Subject | Re: [PATCH] Performance Improvement in CRC16 Calculations. | From | Joe Perches <> | Date | Fri, 10 Aug 2018 12:23:06 -0700 |
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On Fri, 2018-08-10 at 14:12 -0500, Jeff Lien wrote: > This patch provides a performance improvement for the CRC16 calculations done in read/write > workloads using the T10 Type 1/2/3 guard field. For example, today with sequential write > workloads (one thread/CPU of IO) we consume 100% of the CPU because of the CRC16 computation > bottleneck. Today's block devices are considerably faster, but the CRC16 calculation prevents > folks from utilizing the throughput of such devices. To speed up this calculation and expose > the block device throughput, we slice the old single byte for loop into a 16 byte for loop, > with a larger CRC table to match. The result has shown 5x performance improvements on various > big endian and little endian systems running the 4.18.0 kernel version.
Thanks.
This seems a sensible tradeoff for the 4k text size increase.
> diff --git a/crypto/crct10dif_common.c b/crypto/crct10dif_common.c
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trivia:
> +static const __u16 t10_dif_crc_table[16][256] = { > + { > + 0x0000u, 0x8BB7u, 0x9CD9u, 0x176Eu, 0xB205u, 0x39B2u, 0x2EDCu, 0xA56Bu,
All the 'u's are unnecessary visual noise.
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