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2017-09-08squashfs: Add zstd supportSean Purcell
Add zstd compression and decompression support to SquashFS. zstd is a great fit for SquashFS because it can compress at ratios approaching xz, while decompressing twice as fast as zlib. For SquashFS in particular, it can decompress as fast as lzo and lz4. It also has the flexibility to turn down the compression ratio for faster compression times. The compression benchmark is run on the file tree from the SquashFS archive found in ubuntu-16.10-desktop-amd64.iso [1]. It uses `mksquashfs` with the default block size (128 KB) and and various compression algorithms/levels. xz and zstd are also benchmarked with 256 KB blocks. The decompression benchmark times how long it takes to `tar` the file tree into `/dev/null`. See the benchmark file in the upstream zstd source repository located under `contrib/linux-kernel/squashfs-benchmark.sh` [2] for details. I ran the benchmarks on a Ubuntu 14.04 VM with 2 cores and 4 GiB of RAM. The VM is running on a MacBook Pro with a 3.1 GHz Intel Core i7 processor, 16 GB of RAM, and a SSD. | Method | Ratio | Compression MB/s | Decompression MB/s | |----------------|-------|------------------|--------------------| | gzip | 2.92 | 15 | 128 | | lzo | 2.64 | 9.5 | 217 | | lz4 | 2.12 | 94 | 218 | | xz | 3.43 | 5.5 | 35 | | xz 256 KB | 3.53 | 5.4 | 40 | | zstd 1 | 2.71 | 96 | 210 | | zstd 5 | 2.93 | 69 | 198 | | zstd 10 | 3.01 | 41 | 225 | | zstd 15 | 3.13 | 11.4 | 224 | | zstd 16 256 KB | 3.24 | 8.1 | 210 | This patch was written by Sean Purcell <me@seanp.xyz>, but I will be taking over the submission process. [1] http://releases.ubuntu.com/16.10/ [2] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/squashfs-benchmark.sh zstd source repository: https://github.com/facebook/zstd Signed-off-by: Sean Purcell <me@seanp.xyz> Signed-off-by: Nick Terrell <terrelln@fb.com> Signed-off-by: Chris Mason <clm@fb.com> Acked-by: Phillip Lougher <phillip@squashfs.org.uk>
2014-11-27Squashfs: Add LZ4 compression configuration optionPhillip Lougher
Add the glue code, and also update the documentation. Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
2013-11-20Squashfs: Directly decompress into the page cache for file dataPhillip Lougher
This introduces an implementation of squashfs_readpage_block() that directly decompresses into the page cache. This uses the previously added page handler abstraction to push down the necessary kmap_atomic/kunmap_atomic operations on the page cache buffers into the decompressors. This enables direct copying into the page cache without using the slow kmap/kunmap calls. The code detects when multiple threads are racing in squashfs_readpage() to decompress the same block, and avoids this regression by falling back to using an intermediate buffer. This patch enhances the performance of Squashfs significantly when multiple processes are accessing the filesystem simultaneously because it not only reduces memcopying, but it more importantly eliminates the lock contention on the intermediate buffer. Using single-thread decompression. dd if=file1 of=/dev/null bs=4096 & dd if=file2 of=/dev/null bs=4096 & dd if=file3 of=/dev/null bs=4096 & dd if=file4 of=/dev/null bs=4096 Before: 629145600 bytes (629 MB) copied, 45.8046 s, 13.7 MB/s After: 629145600 bytes (629 MB) copied, 9.29414 s, 67.7 MB/s Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reviewed-by: Minchan Kim <minchan@kernel.org>
2013-11-20Squashfs: add multi-threaded decompression using percpu variablePhillip Lougher
Add a multi-threaded decompression implementation which uses percpu variables. Using percpu variables has advantages and disadvantages over implementations which do not use percpu variables. Advantages: * the nature of percpu variables ensures decompression is load-balanced across the multiple cores. * simplicity. Disadvantages: it limits decompression to one thread per core. Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
2013-11-20squashfs: Enhance parallel I/OMinchan Kim
Now squashfs have used for only one stream buffer for decompression so it hurts parallel read performance so this patch supports multiple decompressor to enhance performance parallel I/O. Four 1G file dd read on KVM machine which has 2 CPU and 4G memory. dd if=test/test1.dat of=/dev/null & dd if=test/test2.dat of=/dev/null & dd if=test/test3.dat of=/dev/null & dd if=test/test4.dat of=/dev/null & old : 1m39s -> new : 9s * From v1 * Change comp_strm with decomp_strm - Phillip * Change/add comments - Phillip Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
2011-11-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-nextLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next: Squashfs: Add an option to set dev block size to 4K
2011-11-02Squashfs: Add an option to set dev block size to 4KPhillip Lougher
This commit adds an option to set the device block size used to 4K. By default Squashfs sets the device block size (sb_min_blocksize) to 1K or the smallest block size supported by the block device (if larger). This, because blocks are packed together and unaligned in Squashfs, should reduce latency. This, however, gives poor performance on MTD NAND devices where the optimal I/O size is 4K (even though the devices can support smaller block sizes). Using a 4K device block size may also improve overall I/O performance for some file access patterns (e.g. sequential accesses of files in filesystem order) on all media. Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
2011-09-27doc: fix broken referencesPaul Bolle
There are numerous broken references to Documentation files (in other Documentation files, in comments, etc.). These broken references are caused by typo's in the references, and by renames or removals of the Documentation files. Some broken references are simply odd. Fix these broken references, sometimes by dropping the irrelevant text they were part of. Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-07-22Squashfs: Make ZLIB compression support optionalPhillip Lougher
Squashfs now supports XZ and LZO compression in addition to ZLIB. As such it no longer makes sense to always include ZLIB support. In particular embedded systems may only use LZO or XZ compression, and the ability to exclude ZLIB support will reduce kernel size. Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
2011-05-10treewide: fix a few typos in commentsJustin P. Mattock
- kenrel -> kernel - whetehr -> whether - ttt -> tt - sss -> ss Signed-off-by: Justin P. Mattock <justinmattock@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-02-28Squashfs: Update Kconfig help text to include xz compressionPhillip Lougher
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2011-01-13Squashfs: get rid of default n in KconfigPhillip Lougher
As pointed out by Geert Uytterhoeven, "default n" is the default, no reason to specify it. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2011-01-13Squashfs: Add XZ compression configuration optionPhillip Lougher
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2010-08-05Squashfs: update Kconfig and documentation for LZOPhillip Lougher
Update compression types supported and add some help text for the LZO Kconfig option. Also add missing "default n" line and make some trivial whitespace cleanups too. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2010-08-05Squashfs: Add LZO compression supportChan Jeong
Signed-off-by: Chan Jeong <chan.jeong@lge.com> Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2010-05-31Squashfs: Make XATTR config name consistent with other file systemsPhillip Lougher
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2010-05-17squashfs: add xattr support configure optionPhillip Lougher
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2009-01-22fs/Kconfig: move squashfs outAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>