[linux] Add summaries to xxhash and zstd patches

This commit is contained in:
Nick Terrell 2017-06-21 15:19:54 -07:00
parent 34b0a0883a
commit f3ad4062ba
2 changed files with 241 additions and 11 deletions

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@ -1,3 +1,86 @@
From 36b990a005e68a30495e2b2981e30c5ce97a8591 Mon Sep 17 00:00:00 2001
From: Nick Terrell <terrelln@fb.com>
Date: Mon, 12 Jun 2017 12:13:48 -0700
Subject: [PATCH 1/4] lib: Add xxhash module
Adds xxhash kernel module with xxh32 and xxh64 hashes. xxhash is an
extremely fast non-cryptographic hash algorithm for checksumming.
The zstd compression and decompression modules added in the next patch
require xxhash. I extracted it out from zstd since it is useful on its
own. I copied the code from the upstream XXHash source repository and
translated it into kernel style. I ran benchmarks and tests in the kernel
and tests in userland.
I benchmarked xxhash as a special character device. I ran in four modes,
no-op, xxh32, xxh64, and crc32. The no-op mode simply copies the data to
kernel space and ignores it. The xxh32, xxh64, and crc32 modes compute
hashes on the copied data. I also ran it with four different buffer sizes.
The benchmark file is located in the upstream zstd source repository under
`contrib/linux-kernel/xxhash_test.c` [1].
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. I benchmarked using the file `filesystem.squashfs`
from `ubuntu-16.10-desktop-amd64.iso`, which is 1,536,217,088 B large.
Run the following commands for the benchmark:
modprobe xxhash_test
mknod xxhash_test c 245 0
time cp filesystem.squashfs xxhash_test
The time is reported by the time of the userland `cp`.
The GB/s is computed with
1,536,217,008 B / time(buffer size, hash)
which includes the time to copy from userland.
The Normalized GB/s is computed with
1,536,217,088 B / (time(buffer size, hash) - time(buffer size, none)).
| Buffer Size (B) | Hash | Time (s) | GB/s | Adjusted GB/s |
|-----------------|-------|----------|------|---------------|
| 1024 | none | 0.408 | 3.77 | - |
| 1024 | xxh32 | 0.649 | 2.37 | 6.37 |
| 1024 | xxh64 | 0.542 | 2.83 | 11.46 |
| 1024 | crc32 | 1.290 | 1.19 | 1.74 |
| 4096 | none | 0.380 | 4.04 | - |
| 4096 | xxh32 | 0.645 | 2.38 | 5.79 |
| 4096 | xxh64 | 0.500 | 3.07 | 12.80 |
| 4096 | crc32 | 1.168 | 1.32 | 1.95 |
| 8192 | none | 0.351 | 4.38 | - |
| 8192 | xxh32 | 0.614 | 2.50 | 5.84 |
| 8192 | xxh64 | 0.464 | 3.31 | 13.60 |
| 8192 | crc32 | 1.163 | 1.32 | 1.89 |
| 16384 | none | 0.346 | 4.43 | - |
| 16384 | xxh32 | 0.590 | 2.60 | 6.30 |
| 16384 | xxh64 | 0.466 | 3.30 | 12.80 |
| 16384 | crc32 | 1.183 | 1.30 | 1.84 |
Tested in userland using the test-suite in the zstd repo under
`contrib/linux-kernel/test/XXHashUserlandTest.cpp` [2] by mocking the
kernel functions. A line in each branch of every function in `xxhash.c`
was commented out to ensure that the test-suite fails. Additionally
tested while testing zstd and with SMHasher [3].
[1] https://phabricator.intern.facebook.com/P57526246
[2] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/test/XXHashUserlandTest.cpp
[3] https://github.com/aappleby/smhasher
zstd source repository: https://github.com/facebook/zstd
XXHash source repository: https://github.com/cyan4973/xxhash
Signed-off-by: Nick Terrell <terrelln@fb.com>
---
include/linux/xxhash.h | 236 +++++++++++++++++++++++
lib/Kconfig | 3 +
lib/Makefile | 1 +
lib/xxhash.c | 500 +++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 740 insertions(+)
create mode 100644 include/linux/xxhash.h
create mode 100644 lib/xxhash.c
diff --git a/include/linux/xxhash.h b/include/linux/xxhash.h
new file mode 100644
index 0000000..9e1f42c
@ -241,10 +324,10 @@ index 0000000..9e1f42c
+
+#endif /* XXHASH_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 0c8b78a..b6009d7 100644
index 260a80e..9db178f 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -184,6 +184,9 @@ config CRC8
@@ -185,6 +185,9 @@ config CRC8
when they need to do cyclic redundancy check according CRC8
algorithm. Module will be called crc8.
@ -255,10 +338,10 @@ index 0c8b78a..b6009d7 100644
bool
depends on AUDIT && !AUDIT_ARCH
diff --git a/lib/Makefile b/lib/Makefile
index 320ac46..e16f94a 100644
index 50144a3..5644bad 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -101,6 +101,7 @@ obj-$(CONFIG_CRC32_SELFTEST) += crc32test.o
@@ -93,6 +93,7 @@ obj-$(CONFIG_CRC32) += crc32.o
obj-$(CONFIG_CRC7) += crc7.o
obj-$(CONFIG_LIBCRC32C) += libcrc32c.o
obj-$(CONFIG_CRC8) += crc8.o
@ -772,3 +855,6 @@ index 0000000..dc94904
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("xxHash");
--
2.9.3

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@ -1,3 +1,145 @@
From 536a2c59c5bc58f526e69dd0a35b83d39508ae74 Mon Sep 17 00:00:00 2001
From: Nick Terrell <terrelln@fb.com>
Date: Wed, 21 Jun 2017 14:56:21 -0700
Subject: [PATCH 2/4] lib: Add zstd modules
Add zstd compression and decompression kernel modules.
zstd offers a wide varity of compression speed and quality trade-offs.
It can compress at speeds approaching lz4, and quality approaching lzma.
zstd decompressions at speeds more than twice as fast as zlib, and
decompression speed remains roughly the same across all compression levels.
The code was ported from the upstream zstd source repository. The
`linux/zstd.h` header was modified to match linux kernel style.
The cross-platform and allocation code was stripped out. Instead zstd
requires the caller to pass a preallocated workspace. The source files
were clang-formatted [1] to match the Linux Kernel style as much as
possible. Otherwise, the code was unmodified. We would like to avoid
as much further manual modification to the source code as possible, so it
will be easier to keep the kernel zstd up to date.
I benchmarked zstd compression as a special character device. I ran zstd
and zlib compression at several levels, as well as performing no
compression, which measure the time spent copying the data to kernel space.
Data is passed to the compresser 4096 B at a time. The benchmark file is
located in the upstream zstd source repository under
`contrib/linux-kernel/zstd_compress_test.c` [2].
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. I benchmarked using `silesia.tar` [3], which is
211,988,480 B large. Run the following commands for the benchmark:
sudo modprobe zstd_compress_test
sudo mknod zstd_compress_test c 245 0
sudo cp silesia.tar zstd_compress_test
The time is reported by the time of the userland `cp`.
The MB/s is computed with
1,536,217,008 B / time(buffer size, hash)
which includes the time to copy from userland.
The Adjusted MB/s is computed with
1,536,217,088 B / (time(buffer size, hash) - time(buffer size, none)).
The memory reported is the amount of memory the compressor requests.
| Method | Size (B) | Time (s) | Ratio | MB/s | Adj MB/s | Mem (MB) |
|----------|----------|----------|-------|---------|----------|----------|
| none | 11988480 | 0.100 | 1 | 2119.88 | - | - |
| zstd -1 | 73645762 | 1.044 | 2.878 | 203.05 | 224.56 | 1.23 |
| zstd -3 | 66988878 | 1.761 | 3.165 | 120.38 | 127.63 | 2.47 |
| zstd -5 | 65001259 | 2.563 | 3.261 | 82.71 | 86.07 | 2.86 |
| zstd -10 | 60165346 | 13.242 | 3.523 | 16.01 | 16.13 | 13.22 |
| zstd -15 | 58009756 | 47.601 | 3.654 | 4.45 | 4.46 | 21.61 |
| zstd -19 | 54014593 | 102.835 | 3.925 | 2.06 | 2.06 | 60.15 |
| zlib -1 | 77260026 | 2.895 | 2.744 | 73.23 | 75.85 | 0.27 |
| zlib -3 | 72972206 | 4.116 | 2.905 | 51.50 | 52.79 | 0.27 |
| zlib -6 | 68190360 | 9.633 | 3.109 | 22.01 | 22.24 | 0.27 |
| zlib -9 | 67613382 | 22.554 | 3.135 | 9.40 | 9.44 | 0.27 |
I benchmarked zstd decompression using the same method on the same machine.
The benchmark file is located in the upstream zstd repo under
`contrib/linux-kernel/zstd_decompress_test.c` [4]. The memory reported is
the amount of memory required to decompress data compressed with the given
compression level. If you know the maximum size of your input, you can
reduce the memory usage of decompression irrespective of the compression
level.
| Method | Time (s) | MB/s | Adjusted MB/s | Memory (MB) |
|----------|----------|---------|---------------|-------------|
| none | 0.025 | 8479.54 | - | - |
| zstd -1 | 0.358 | 592.15 | 636.60 | 0.84 |
| zstd -3 | 0.396 | 535.32 | 571.40 | 1.46 |
| zstd -5 | 0.396 | 535.32 | 571.40 | 1.46 |
| zstd -10 | 0.374 | 566.81 | 607.42 | 2.51 |
| zstd -15 | 0.379 | 559.34 | 598.84 | 4.61 |
| zstd -19 | 0.412 | 514.54 | 547.77 | 8.80 |
| zlib -1 | 0.940 | 225.52 | 231.68 | 0.04 |
| zlib -3 | 0.883 | 240.08 | 247.07 | 0.04 |
| zlib -6 | 0.844 | 251.17 | 258.84 | 0.04 |
| zlib -9 | 0.837 | 253.27 | 287.64 | 0.04 |
Tested in userland using the test-suite in the zstd repo under
`contrib/linux-kernel/test/UserlandTest.cpp` [5] by mocking the kernel
functions. Fuzz tested using libfuzzer [6] with the fuzz harnesses under
`contrib/linux-kernel/test/{RoundTripCrash.c,DecompressCrash.c}` [7] [8]
with ASAN, UBSAN, and MSAN. Additionaly, it was tested while testing the
BtrFS and SquashFS patches coming next.
[1] https://clang.llvm.org/docs/ClangFormat.html
[2] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/zstd_compress_test.c
[3] http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia
[4] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/zstd_decompress_test.c
[5] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/test/UserlandTest.cpp
[6] http://llvm.org/docs/LibFuzzer.html
[7] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/test/RoundTripCrash.c
[8] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/test/DecompressCrash.c
zstd source repository: https://github.com/facebook/zstd
Signed-off-by: Nick Terrell <terrelln@fb.com>
---
include/linux/zstd.h | 1157 +++++++++++++++
lib/Kconfig | 8 +
lib/Makefile | 2 +
lib/zstd/Makefile | 18 +
lib/zstd/bitstream.h | 374 +++++
lib/zstd/compress.c | 3468 +++++++++++++++++++++++++++++++++++++++++++++
lib/zstd/decompress.c | 2514 ++++++++++++++++++++++++++++++++
lib/zstd/entropy_common.c | 244 ++++
lib/zstd/error_private.h | 53 +
lib/zstd/fse.h | 584 ++++++++
lib/zstd/fse_compress.c | 857 +++++++++++
lib/zstd/fse_decompress.c | 313 ++++
lib/zstd/huf.h | 203 +++
lib/zstd/huf_compress.c | 731 ++++++++++
lib/zstd/huf_decompress.c | 920 ++++++++++++
lib/zstd/mem.h | 151 ++
lib/zstd/zstd_common.c | 75 +
lib/zstd/zstd_internal.h | 269 ++++
lib/zstd/zstd_opt.h | 1014 +++++++++++++
19 files changed, 12955 insertions(+)
create mode 100644 include/linux/zstd.h
create mode 100644 lib/zstd/Makefile
create mode 100644 lib/zstd/bitstream.h
create mode 100644 lib/zstd/compress.c
create mode 100644 lib/zstd/decompress.c
create mode 100644 lib/zstd/entropy_common.c
create mode 100644 lib/zstd/error_private.h
create mode 100644 lib/zstd/fse.h
create mode 100644 lib/zstd/fse_compress.c
create mode 100644 lib/zstd/fse_decompress.c
create mode 100644 lib/zstd/huf.h
create mode 100644 lib/zstd/huf_compress.c
create mode 100644 lib/zstd/huf_decompress.c
create mode 100644 lib/zstd/mem.h
create mode 100644 lib/zstd/zstd_common.c
create mode 100644 lib/zstd/zstd_internal.h
create mode 100644 lib/zstd/zstd_opt.h
diff --git a/include/linux/zstd.h b/include/linux/zstd.h
new file mode 100644
index 0000000..249575e
@ -1162,10 +1304,10 @@ index 0000000..249575e
+
+#endif /* ZSTD_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index b6009d7..f00ddab 100644
index 9db178f..8deab4f 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -241,6 +241,14 @@ config LZ4HC_COMPRESS
@@ -242,6 +242,14 @@ config LZ4HC_COMPRESS
config LZ4_DECOMPRESS
tristate
@ -1181,10 +1323,10 @@ index b6009d7..f00ddab 100644
#
diff --git a/lib/Makefile b/lib/Makefile
index e16f94a..0cfd529 100644
index 5644bad..aa630d4 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -115,6 +115,8 @@ obj-$(CONFIG_LZO_DECOMPRESS) += lzo/
@@ -107,6 +107,8 @@ obj-$(CONFIG_LZO_DECOMPRESS) += lzo/
obj-$(CONFIG_LZ4_COMPRESS) += lz4/
obj-$(CONFIG_LZ4HC_COMPRESS) += lz4/
obj-$(CONFIG_LZ4_DECOMPRESS) += lz4/
@ -13077,3 +13219,5 @@ index 0000000..55e1b4c
+}
+
+#endif /* ZSTD_OPT_H_91842398743 */
--
2.9.3