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>
34 lines
1,012 B
Text
34 lines
1,012 B
Text
config ZRAM
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tristate "Compressed RAM block device support"
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depends on BLOCK && SYSFS && ZSMALLOC
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select LZO_COMPRESS
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select LZO_DECOMPRESS
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default n
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help
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Creates virtual block devices called /dev/zramX (X = 0, 1, ...).
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Pages written to these disks are compressed and stored in memory
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itself. These disks allow very fast I/O and compression provides
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good amounts of memory savings.
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It has several use cases, for example: /tmp storage, use as swap
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disks and maybe many more.
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See zram.txt for more information.
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config ZRAM_LZ4_COMPRESS
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bool "Enable LZ4 algorithm support"
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depends on ZRAM
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select LZ4_COMPRESS
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select LZ4_DECOMPRESS
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default n
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help
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This option enables LZ4 compression algorithm support. Compression
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algorithm can be changed using `comp_algorithm' device attribute.
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config ZRAM_DEBUG
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bool "Compressed RAM block device debug support"
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depends on ZRAM
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default n
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help
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This option adds additional debugging code to the compressed
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RAM block device driver.
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