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6e76668e41
Introduce LZ4 compression backend and make it available for selection.
LZ4 support is optional and requires user to set ZRAM_LZ4_COMPRESS config
option. The default compression backend is LZO.
TEST
(x86_64, core i5, 2 cores + 2 hyperthreading, zram disk size 1G,
ext4 file system, 3 compression streams)
iozone -t 3 -R -r 16K -s 60M -I +Z
Test LZO LZ4
----------------------------------------------
Initial write 1642744.62 1317005.09
Rewrite 2498980.88 1800645.16
Read 3957026.38 5877043.75
Re-read 3950997.38 5861847.00
Reverse Read 2937114.56 5047384.00
Stride read 2948163.19 4929587.38
Random read 3292692.69 4880793.62
Mixed workload 1545602.62 3502940.38
Random write 2448039.75 1758786.25
Pwrite 1670051.03 1338329.69
Pread 2530682.00 5097177.62
Fwrite 3232085.62 3275942.56
Fread 6306880.25 6645271.12
So on my system LZ4 is slower in write-only tests, while it performs
better in read-only and mixed (reads + writes) tests.
Official LZ4 benchmarks available here http://code.google.com/p/lz4/
(linux kernel uses revision r90).
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
48 lines
1.2 KiB
C
48 lines
1.2 KiB
C
/*
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* Copyright (C) 2014 Sergey Senozhatsky.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/lz4.h>
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#include "zcomp_lz4.h"
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static void *zcomp_lz4_create(void)
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{
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return kzalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
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}
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static void zcomp_lz4_destroy(void *private)
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{
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kfree(private);
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}
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static int zcomp_lz4_compress(const unsigned char *src, unsigned char *dst,
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size_t *dst_len, void *private)
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{
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/* return : Success if return 0 */
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return lz4_compress(src, PAGE_SIZE, dst, dst_len, private);
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}
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static int zcomp_lz4_decompress(const unsigned char *src, size_t src_len,
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unsigned char *dst)
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{
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size_t dst_len = PAGE_SIZE;
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/* return : Success if return 0 */
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return lz4_decompress_unknownoutputsize(src, src_len, dst, &dst_len);
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}
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struct zcomp_backend zcomp_lz4 = {
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.compress = zcomp_lz4_compress,
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.decompress = zcomp_lz4_decompress,
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.create = zcomp_lz4_create,
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.destroy = zcomp_lz4_destroy,
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.name = "lz4",
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};
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