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src/third_party/zstd-1.2.0/contrib/linux-kernel/README.md
In zstdr: R Bindings to the 'Zstandard' Compression Library
Linux Kernel Patch
There are three pieces, the zstd_compress and zstd_decompress kernel modules, the BtrFS patch, and the SquashFS patch.
The patches are based off of the linux kernel master branch (version 4.10).
Zstd Kernel modules
- The header is in
include/linux/zstd.h.
- It is split up into
zstd_compress and zstd_decompress, which can be loaded independently.
- Source files are in
lib/zstd/.
lib/Kconfig and lib/Makefile need to be modified by applying lib/Kconfig.diff and lib/Makefile.diff respectively.test/UserlandTest.cpp contains tests for the patch in userland by mocking the kernel headers.
It can be run with the following commands:
cd test
make googletest
make UserlandTest
./UserlandTest
BtrFS
- The patch is located in
btrfs.diff.
- Additionally
fs/btrfs/zstd.c is provided as a source for convenience.
- The patch seems to be working, it doesn't crash the kernel, and compresses at speeds and ratios that are expected.
It could still use some more testing for fringe features, like printing options.
Benchmarks
Benchmarks run on a Ubuntu 14.04 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.
The kernel running was built from the master branch with the patch (version 4.10).
The compression benchmark is copying 10 copies of the
unzipped silesia corpus into a BtrFS
filesystem mounted with -o compress-force={none, lzo, zlib, zstd}.
The decompression benchmark is timing how long it takes to tar all 10 copies
into /dev/null.
The compression ratio is measured by comparing the output of df and du.
See btrfs-benchmark.sh for details.
| Algorithm | Compression ratio | Compression speed | Decompression speed |
|-----------|-------------------|-------------------|---------------------|
| None | 0.99 | 504 MB/s | 686 MB/s |
| lzo | 1.66 | 398 MB/s | 442 MB/s |
| zlib | 2.58 | 65 MB/s | 241 MB/s |
| zstd 1 | 2.57 | 260 MB/s | 383 MB/s |
| zstd 3 | 2.71 | 174 MB/s | 408 MB/s |
| zstd 6 | 2.87 | 70 MB/s | 398 MB/s |
| zstd 9 | 2.92 | 43 MB/s | 406 MB/s |
| zstd 12 | 2.93 | 21 MB/s | 408 MB/s |
| zstd 15 | 3.01 | 11 MB/s | 354 MB/s |
SquashFS
- The patch is located in
squashfs.diff
- Additionally
fs/squashfs/zstd_wrapper.c is provided as a source for convenience.
- The patch has been tested on a 4.10 kernel.
Benchmarks
Benchmarks run on a Ubuntu 14.04 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.
The kernel running was built from the master branch with the patch (version 4.10).
The compression benchmark is the file tree from the SquashFS archive found in the
Ubuntu 16.10 desktop image (ubuntu-16.10-desktop-amd64.iso).
The compression benchmark uses mksquashfs with the default block size (128 KB)
and various compression algorithms/compression levels.
xz and zstd are also benchmarked with 256 KB blocks.
The decompression benchmark is timing how long it takes to tar the file tree
into /dev/null.
See squashfs-benchmark.sh for details.
| Algorithm | Compression ratio | Compression speed | Decompression speed |
|----------------|-------------------|-------------------|---------------------|
| gzip | 2.92 | 15 MB/s | 128 MB/s |
| lzo | 2.64 | 9.5 MB/s | 217 MB/s |
| lz4 | 2.12 | 94 MB/s | 218 MB/s |
| xz | 3.43 | 5.5 MB/s | 35 MB/s |
| xz 256 KB | 3.53 | 5.4 MB/s | 40 MB/s |
| zstd 1 | 2.71 | 96 MB/s | 210 MB/s |
| zstd 5 | 2.93 | 69 MB/s | 198 MB/s |
| zstd 10 | 3.01 | 41 MB/s | 225 MB/s |
| zstd 15 | 3.13 | 11.4 MB/s | 224 MB/s |
| zstd 16 256 KB | 3.24 | 8.1 MB/s | 210 MB/s |
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Linux Kernel Patch
There are three pieces, the zstd_compress and zstd_decompress kernel modules, the BtrFS patch, and the SquashFS patch.
The patches are based off of the linux kernel master branch (version 4.10).
Zstd Kernel modules
- The header is in
include/linux/zstd.h. - It is split up into
zstd_compressandzstd_decompress, which can be loaded independently. - Source files are in
lib/zstd/. lib/Kconfigandlib/Makefileneed to be modified by applyinglib/Kconfig.diffandlib/Makefile.diffrespectively.test/UserlandTest.cppcontains tests for the patch in userland by mocking the kernel headers. It can be run with the following commands:cd test make googletest make UserlandTest ./UserlandTest
BtrFS
- The patch is located in
btrfs.diff. - Additionally
fs/btrfs/zstd.cis provided as a source for convenience. - The patch seems to be working, it doesn't crash the kernel, and compresses at speeds and ratios that are expected. It could still use some more testing for fringe features, like printing options.
Benchmarks
Benchmarks run on a Ubuntu 14.04 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. The kernel running was built from the master branch with the patch (version 4.10).
The compression benchmark is copying 10 copies of the
unzipped silesia corpus into a BtrFS
filesystem mounted with -o compress-force={none, lzo, zlib, zstd}.
The decompression benchmark is timing how long it takes to tar all 10 copies
into /dev/null.
The compression ratio is measured by comparing the output of df and du.
See btrfs-benchmark.sh for details.
| Algorithm | Compression ratio | Compression speed | Decompression speed | |-----------|-------------------|-------------------|---------------------| | None | 0.99 | 504 MB/s | 686 MB/s | | lzo | 1.66 | 398 MB/s | 442 MB/s | | zlib | 2.58 | 65 MB/s | 241 MB/s | | zstd 1 | 2.57 | 260 MB/s | 383 MB/s | | zstd 3 | 2.71 | 174 MB/s | 408 MB/s | | zstd 6 | 2.87 | 70 MB/s | 398 MB/s | | zstd 9 | 2.92 | 43 MB/s | 406 MB/s | | zstd 12 | 2.93 | 21 MB/s | 408 MB/s | | zstd 15 | 3.01 | 11 MB/s | 354 MB/s |
SquashFS
- The patch is located in
squashfs.diff - Additionally
fs/squashfs/zstd_wrapper.cis provided as a source for convenience. - The patch has been tested on a 4.10 kernel.
Benchmarks
Benchmarks run on a Ubuntu 14.04 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. The kernel running was built from the master branch with the patch (version 4.10).
The compression benchmark is the file tree from the SquashFS archive found in the
Ubuntu 16.10 desktop image (ubuntu-16.10-desktop-amd64.iso).
The compression benchmark uses mksquashfs with the default block size (128 KB)
and various compression algorithms/compression levels.
xz and zstd are also benchmarked with 256 KB blocks.
The decompression benchmark is timing how long it takes to tar the file tree
into /dev/null.
See squashfs-benchmark.sh for details.
| Algorithm | Compression ratio | Compression speed | Decompression speed | |----------------|-------------------|-------------------|---------------------| | gzip | 2.92 | 15 MB/s | 128 MB/s | | lzo | 2.64 | 9.5 MB/s | 217 MB/s | | lz4 | 2.12 | 94 MB/s | 218 MB/s | | xz | 3.43 | 5.5 MB/s | 35 MB/s | | xz 256 KB | 3.53 | 5.4 MB/s | 40 MB/s | | zstd 1 | 2.71 | 96 MB/s | 210 MB/s | | zstd 5 | 2.93 | 69 MB/s | 198 MB/s | | zstd 10 | 3.01 | 41 MB/s | 225 MB/s | | zstd 15 | 3.13 | 11.4 MB/s | 224 MB/s | | zstd 16 256 KB | 3.24 | 8.1 MB/s | 210 MB/s |
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Note that we can't provide technical support on individual packages. You should contact the package authors for that.
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