Re: [PATCH] Performance Improvement in CRC16 Calculations.
flat view
From: Joe Perches <joe@perches.com>
Date: 2018-08-10 19:24:45
Also in:
linux-crypto, linux-scsi, lkml
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.
quoted hunk ↗ jump to hunk
diff --git a/crypto/crct10dif_common.c b/crypto/crct10dif_common.c
[] trivia:
quoted hunk ↗ jump to hunk
+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.