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Linux kernel source tree
65d1f5507e
In addition to keeping the kernel's copy of zstd up to date, this update was requested by Intel to expose upstream's APIs that allow QAT to accelerate the LZ match finding stage of Zstd. This patch is imported from the upstream tag v1.5.7-kernel [0], which is signed with upstream's signing key EF8FE99528B52FFD [1]. It was imported from upstream using this command: export ZSTD=/path/to/repo/zstd/ export LINUX=/path/to/repo/linux/ cd "$ZSTD/contrib/linux-kernel" git checkout v1.5.7-kernel make import LINUX="$LINUX" This patch has been tested on x86-64, and has been boot tested with a zstd compressed kernel & initramfs on i386 and aarch64. I benchmarked the patch on x86-64 with gcc-14.2.1 on an Intel i9-9900K by measruing the performance of compressed filesystem reads and writes. Component, Level, Size delta, C. time delta, D. time delta Btrfs , 1, +0.00%, -6.1%, +1.4% Btrfs , 3, +0.00%, -9.8%, +3.0% Btrfs , 5, +0.00%, +1.7%, +1.4% Btrfs , 7, +0.00%, -1.9%, +2.7% Btrfs , 9, +0.00%, -3.4%, +3.7% Btrfs , 15, +0.00%, -0.3%, +3.6% SquashFS , 1, +0.00%, N/A, +1.9% The major changes that impact the kernel use cases for each version are: v1.5.7: https://github.com/facebook/zstd/releases/tag/v1.5.7 * Add zstd_compress_sequences_and_literals() for use by Intel's QAT driver to implement Zstd compression acceleration in the kernel. * Fix an underflow bug in 32-bit builds that can cause data corruption when processing more than 4GB of data with a single `ZSTD_CCtx` object, when an input crosses the 4GB boundry. I don't believe this impacts any current kernel use cases, because the `ZSTD_CCtx` is typically reconstructed between compressions. * Levels 1-4 see 5-10% compression speed improvements for inputs smaller than 128KB. v1.5.6: https://github.com/facebook/zstd/releases/tag/v1.5.6 * Improved compression ratio for the highest compression levels. I don't expect these see much use however, due to their slow speeds. v1.5.5: https://github.com/facebook/zstd/releases/tag/v1.5.5 * Fix a rare corruption bug that can trigger on levels 13 and above. * Improve compression speed of levels 5-11 on incompressible data. v1.5.4: https://github.com/facebook/zstd/releases/tag/v1.5.4 * Improve copmression speed of levels 5-11 on ARM. * Improve dictionary compression speed. Signed-off-by: Nick Terrell <terrelln@fb.com> |
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| kernel | ||
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| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.