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authorDavid Sterba <dsterba@suse.com>2023-04-04 01:06:02 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-07-27 09:44:37 +0300
commitae51eb90bcca2f8a9e4b76fe35cc76df0d915621 (patch)
tree82788800aedd91331a44d9c4401bc0a8d7124b36
parent322377cc909defcca9451487484845e7e1d20d1b (diff)
downloadlinux-ae51eb90bcca2f8a9e4b76fe35cc76df0d915621.tar.xz
btrfs: add xxhash to fast checksum implementations
[ Upstream commit efcfcbc6a36195c42d98e0ee697baba36da94dc8 ] The implementation of XXHASH is now CPU only but still fast enough to be considered for the synchronous checksumming, like non-generic crc32c. A userspace benchmark comparing it to various implementations (patched hash-speedtest from btrfs-progs): Block size: 4096 Iterations: 1000000 Implementation: builtin Units: CPU cycles NULL-NOP: cycles: 73384294, cycles/i 73 NULL-MEMCPY: cycles: 228033868, cycles/i 228, 61664.320 MiB/s CRC32C-ref: cycles: 24758559416, cycles/i 24758, 567.950 MiB/s CRC32C-NI: cycles: 1194350470, cycles/i 1194, 11773.433 MiB/s CRC32C-ADLERSW: cycles: 6150186216, cycles/i 6150, 2286.372 MiB/s CRC32C-ADLERHW: cycles: 626979180, cycles/i 626, 22427.453 MiB/s CRC32C-PCL: cycles: 466746732, cycles/i 466, 30126.699 MiB/s XXHASH: cycles: 860656400, cycles/i 860, 16338.188 MiB/s Comparing purely software implementation (ref), current outdated accelerated using crc32q instruction (NI), optimized implementations by M. Adler (https://stackoverflow.com/questions/17645167/implementing-sse-4-2s-crc32c-in-software/17646775#17646775) and the best one that was taken from kernel using the PCLMULQDQ instruction (PCL). Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--fs/btrfs/disk-io.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5a114cad988a..608b939a4d28 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2256,6 +2256,9 @@ static int btrfs_init_csum_hash(struct btrfs_fs_info *fs_info, u16 csum_type)
if (!strstr(crypto_shash_driver_name(csum_shash), "generic"))
set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
break;
+ case BTRFS_CSUM_TYPE_XXHASH:
+ set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
+ break;
default:
break;
}