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4 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Nick Terrell
|
98988fc8e9 |
zstd: import upstream v1.5.5
Import upstream zstd v1.5.5 to expose upstream's QAT integration.
Import from upstream commit 58b3ef79 [0]. This is one commit before the
tag v1.5.5-kernel [1], which is signed with upstream's signing key. The
next patch in the series imports from v1.5.5-kernel, and is included in
the series, rather than just importing directly from v1.5.5-kernel,
because it is a non-trivial patch applied to improve the kernel's
decompression speed. This commit contains 3 backported patches on top of
v1.5.5: Two from the Linux copy of zstd, and one from upstream's `dev`
branch.
In addition to keeping the kernel's copy of zstd up to date, this update
was requested by Intel to expose upstream zstd's external match provider
API to the kernel, which allows QAT to accelerate the LZ match finding
stage.
This commit was generated by:
export ZSTD=/path/to/repo/zstd/
export LINUX=/path/to/repo/linux/
cd "$ZSTD/contrib/linux-kernel"
git checkout v1.5.5-kernel~
make import LINUX="$LINUX"
I tested and benchmarked this commit on x86-64 with gcc-13.2.1 on an
Intel i9-9900K by running my benchmark scripts that benchmark zstd's
performance in btrfs and squashfs compressed filesystems. This commit
improves compression speed, especially for higher compression levels,
and regresses decompression speed. But the decompression speed
regression is addressed by the next patch in the series.
Component, Level, C. time delta, size delta, D. time delta
Btrfs , 1, -1.9%, +0.0%, +9.5%
Btrfs , 3, -5.6%, +0.0%, +7.4%
Btrfs , 5, -4.9%, +0.0%, +5.0%
Btrfs , 7, -5.7%, +0.0%, +5.2%
Btrfs , 9, -5.7%, +0.0%, +4.0%
Squashfs , 1, N/A, 0.0%, +11.6%
I also boot tested with a zstd compressed kernel on i386 and aarch64.
Link:
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Nick Terrell
|
2aa14b1ab2 |
zstd: import usptream v1.5.2
Updates the kernel's zstd library to v1.5.2, the latest zstd release. The upstream tag it is updated to is `v1.5.2-kernel`, which contains several cherry-picked commits on top of the v1.5.2 release which are required for the kernel update. I will create this tag once the PR is ready to merge, until then reference the temporary upstream branch `v1.5.2-kernel-cherrypicks`. I plan to submit this patch as part of the v6.2 merge window. I've done basic build testing & testing on x86-64, i386, and aarch64. I'm merging these patches into my `zstd-next` branch, which is pulled into `linux-next` for further testing. I've benchmarked BtrFS with zstd compression on a x86-64 machine, and saw these results. Decompression speed is a small win across the board. The lower compression levels 1-4 see both compression speed and compression ratio wins. The higher compression levels see a small compression speed loss and about neutral ratio. I expect the lower compression levels to be used much more heavily than the high compression levels, so this should be a net win. Level CTime DTime Ratio 1 -2.95% -1.1% -0.7% 3 -3.5% -1.2% -0.5% 5 +3.7% -1.0% +0.0% 7 +3.2% -0.9% +0.0% 9 -4.3% -0.8% +0.1% Signed-off-by: Nick Terrell <terrelln@fb.com> |
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Nick Terrell
|
ae8d67b211 |
lib: zstd: Fix unused variable warning
The variable `litLengthSum` is only used by an `assert()`, so when asserts are disabled the compiler doesn't see any usage and warns. This issue is already fixed upstream by PR #2838 [0]. It was reported by the Kernel test robot in [1]. Another approach would be to change zstd's disabled `assert()` definition to use the argument in a disabled branch, instead of ignoring the argument. I've avoided this approach because there are some small changes necessary to get zstd to build, and I would want to thoroughly re-test for performance, since that is slightly changing the code in every function in zstd. It seems like a trivial change, but some functions are pretty sensitive to small changes. However, I think it is a valid approach that I would like to see upstream take, so I've opened Issue #2868 to attempt this upstream. Lastly, I've chosen not to use __maybe_unused because all code in lib/zstd/ must eventually be upstreamed. Upstream zstd can't use __maybe_unused because it isn't portable across all compilers. [0] https://github.com/facebook/zstd/pull/2838 [1] https://lore.kernel.org/linux-mm/202111120312.833wII4i-lkp@intel.com/T/ [2] https://github.com/facebook/zstd/issues/2868 Link: https://lore.kernel.org/r/20211117014949.1169186-2-nickrterrell@gmail.com/ Link: https://lore.kernel.org/r/20211117201459.1194876-2-nickrterrell@gmail.com/ Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Nick Terrell <terrelln@fb.com> |
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Nick Terrell
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e0c1b49f5b |
lib: zstd: Upgrade to latest upstream zstd version 1.4.10
Upgrade to the latest upstream zstd version 1.4.10. This patch is 100% generated from upstream zstd commit 20821a46f412 [0]. This patch is very large because it is transitioning from the custom kernel zstd to using upstream directly. The new zstd follows upstreams file structure which is different. Future update patches will be much smaller because they will only contain the changes from one upstream zstd release. As an aid for review I've created a commit [1] that shows the diff between upstream zstd as-is (which doesn't compile), and the zstd code imported in this patch. The verion of zstd in this patch is generated from upstream with changes applied by automation to replace upstreams libc dependencies, remove unnecessary portability macros, replace `/**` comments with `/*` comments, and use the kernel's xxhash instead of bundling it. The benefits of this patch are as follows: 1. Using upstream directly with automated script to generate kernel code. This allows us to update the kernel every upstream release, so the kernel gets the latest bug fixes and performance improvements, and doesn't get 3 years out of date again. The automation and the translated code are tested every upstream commit to ensure it continues to work. 2. Upgrades from a custom zstd based on 1.3.1 to 1.4.10, getting 3 years of performance improvements and bug fixes. On x86_64 I've measured 15% faster BtrFS and SquashFS decompression+read speeds, 35% faster kernel decompression, and 30% faster ZRAM decompression+read speeds. 3. Zstd-1.4.10 supports negative compression levels, which allow zstd to match or subsume lzo's performance. 4. Maintains the same kernel-specific wrapper API, so no callers have to be modified with zstd version updates. One concern that was brought up was stack usage. Upstream zstd had already removed most of its heavy stack usage functions, but I just removed the last functions that allocate arrays on the stack. I've measured the high water mark for both compression and decompression before and after this patch. Decompression is approximately neutral, using about 1.2KB of stack space. Compression levels up to 3 regressed from 1.4KB -> 1.6KB, and higher compression levels regressed from 1.5KB -> 2KB. We've added unit tests upstream to prevent further regression. I believe that this is a reasonable increase, and if it does end up causing problems, this commit can be cleanly reverted, because it only touches zstd. I chose the bulk update instead of replaying upstream commits because there have been ~3500 upstream commits since the 1.3.1 release, zstd wasn't ready to be used in the kernel as-is before a month ago, and not all upstream zstd commits build. The bulk update preserves bisectablity because bugs can be bisected to the zstd version update. At that point the update can be reverted, and we can work with upstream to find and fix the bug. Note that upstream zstd release 1.4.10 doesn't exist yet. I have cut a staging branch at 20821a46f412 [0] and will apply any changes requested to the staging branch. Once we're ready to merge this update I will cut a zstd release at the commit we merge, so we have a known zstd release in the kernel. The implementation of the kernel API is contained in zstd_compress_module.c and zstd_decompress_module.c. [0] |