This is the Fletcher4 algorithm implemented in pure C, but using
multiple counters using algorithms identical to those used for
SSE/NEON and AVX2.
This allows for faster execution on core with strong superscalar
capabilities but weak SIMD capabilities.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Romain Dolbeau <romain.dolbeau@atos.net>
Closes#5317
This is not useful on micro-architecture with a weak NEON
implementation (only 64 bits); the native version is slower &
the byteswap barely faster than scalar. On A53 or A57, it's
a small improvement on scalar but OK for byteswap.
Results from an A53 system:
0 0 0x01 -1 0 1499068294333000 1499101101878000
implementation native byteswap
scalar 1008227510 755880264
aarch64_neon 1198098720 1044818671
fastest aarch64_neon aarch64_neon
Results from a A57 system:
0 0 0x01 -1 0 4407214734807033 4407233933777404
implementation native byteswap
scalar 2302071241 1124873346
aarch64_neon 2542214946 2245570352
fastest aarch64_neon aarch64_neon
Reviewed-by: Gvozden Neskovic <neskovic@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Romain Dolbeau <romain.dolbeau@atos.net>
Closes#5248
Init, compute, and fini methods are changed to work on internal context object.
This is necessary because ABI does not guarantee that SIMD registers will be preserved
on function calls. This is technically the case in Linux kernel in between
`kfpu_begin()/kfpu_end()`, but it breaks user-space tests and some kernels that
don't require disabling preemption for using SIMD (osx).
Use scalar compute methods in-place for small buffers, and when the buffer size
does not meet SIMD size alignment.
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Combine incrementally computed fletcher4 checksums. Checksums are combined
a posteriori, allowing for parallel computation on chunks to be implemented if
required. The algorithm is general, and does not add changes in each SIMD
implementation.
New test in ztest verifies incremental fletcher computations.
Checksum combining matrix for two buffers `a` and `b`, where `Ca` and `Cb` are
respective fletcher4 checksums, `Cab` is combined checksum, `s` is size of buffer
`b` (divided by sizeof(uint32_t)) is:
Cab[A] = Cb[A] + Ca[A]
Cab[B] = Cb[B] + Ca[B] + s * Ca[A]
Cab[C] = Cb[C] + Ca[C] + s * Ca[B] + s(s+1)/2 * Ca[A]
Cab[D] = Cb[D] + Ca[D] + s * Ca[C] + s(s+1)/2 * Ca[B] + s(s+1)(s+2)/6 * Ca[A]
NOTE: this calculation overflows for larger buffers. Thus, internally, the calculation
is performed on 8MiB chunks.
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Garrett D'Amore <garrett@damore.org>
Ported by: Tony Hutter <hutter2@llnl.gov>
OpenZFS-issue: https://www.illumos.org/issues/4185
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/45818ee
Porting Notes:
This code is ported on top of the Illumos Crypto Framework code:
b5e030c8db
The list of porting changes includes:
- Copied module/icp/include/sha2/sha2.h directly from illumos
- Removed from module/icp/algs/sha2/sha2.c:
#pragma inline(SHA256Init, SHA384Init, SHA512Init)
- Added 'ctx' to lib/libzfs/libzfs_sendrecv.c:zio_checksum_SHA256() since
it now takes in an extra parameter.
- Added CTASSERT() to assert.h from for module/zfs/edonr_zfs.c
- Added skein & edonr to libicp/Makefile.am
- Added sha512.S. It was generated from sha512-x86_64.pl in Illumos.
- Updated ztest.c with new fletcher_4_*() args; used NULL for new CTX argument.
- In icp/algs/edonr/edonr_byteorder.h, Removed the #if defined(__linux) section
to not #include the non-existant endian.h.
- In skein_test.c, renane NULL to 0 in "no test vector" array entries to get
around a compiler warning.
- Fixup test files:
- Rename <sys/varargs.h> -> <varargs.h>, <strings.h> -> <string.h>,
- Remove <note.h> and define NOTE() as NOP.
- Define u_longlong_t
- Rename "#!/usr/bin/ksh" -> "#!/bin/ksh -p"
- Rename NULL to 0 in "no test vector" array entries to get around a
compiler warning.
- Remove "for isa in $($ISAINFO); do" stuff
- Add/update Makefiles
- Add some userspace headers like stdio.h/stdlib.h in places of
sys/types.h.
- EXPORT_SYMBOL *_Init/*_Update/*_Final... routines in ICP modules.
- Update scripts/zfs2zol-patch.sed
- include <sys/sha2.h> in sha2_impl.h
- Add sha2.h to include/sys/Makefile.am
- Add skein and edonr dirs to icp Makefile
- Add new checksums to zpool_get.cfg
- Move checksum switch block from zfs_secpolicy_setprop() to
zfs_check_settable()
- Fix -Wuninitialized error in edonr_byteorder.h on PPC
- Fix stack frame size errors on ARM32
- Don't unroll loops in Skein on 32-bit to save stack space
- Add memory barriers in sha2.c on 32-bit to save stack space
- Add filetest_001_pos.ksh checksum sanity test
- Add option to write psudorandom data in file_write utility
API Change: Module parameter set/get methods take const parameter in
Grsecurity kernel v4.7.1
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Signed-off-by: Jason Zaman <jason@perfinion.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4997Closes#5001
- Benchmark memory block is increased to 128kiB to reflect real block sizes more
accurately. Measurements include all three stages needed for checksum generation,
i.e. `init()/compute()/fini()`. The inner loop is repeated multiple times to offset
overhead of time function.
- Fastest implementation selects native and byteswap methods independently in
benchmark. To support this new function pointers `init_byteswap()/fini_byteswap()`
are introduced.
- Implementation mutex lock is replaced by atomic variable.
- To save time, benchmark is not executed in userspace. Instead, highest supported
implementation is used for fastest. Default userspace selector is still 'cycle'.
- `fletcher_4_native/byteswap()` methods use incremental methods to finish
calculation if data size is not multiple of vector stride (currently 64B).
- Added `fletcher_4_native_varsize()` special purpose method for use when buffer size
is not known in advance. The method does not enforce 4B alignment on buffer size, and
will ignore last (size % 4) bytes of the data buffer.
- Benchmark `kstat` is changed to match the one of vdev_raidz. It now shows
throughput for all supported implementations (in B/s), native and byteswap,
as well as the code [fastest] is running.
Example of `fletcher_4_bench` running on `Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz`:
implementation native byteswap
scalar 4768120823 3426105750
sse2 7947841777 4318964249
ssse3 7951922722 6112191941
avx2 13269714358 11043200912
fastest avx2 avx2
Example of `fletcher_4_bench` running on `Intel(R) Xeon Phi(TM) CPU 7210 @ 1.30GHz`:
implementation native byteswap
scalar 1291115967 1031555336
sse2 2539571138 1280970926
ssse3 2537778746 1080016762
avx2 4950749767 1078493449
avx512f 9581379998 4010029046
fastest avx512f avx512f
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4952
This fix resolves warnings reported during compiling of user-space
libraries with different gcc optimization levels.
Tested with gcc versions: 4.9.2 (Debian), and 6.1.1 (Fedora).
The patch enables use of following opt levels: O0, O1, O2, O3, Og, Os, Ofast.
List of warnings:
[GCC 4.9.2 -Os]
libzfs_sendrecv.c:3726:26: error: 'clp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
[GCC 4.9.2 -Og]
fs_fletcher.c:323:26: error: 'idx' may be used uninitialized in this function [-Werror=maybe-uninitialized]
dsl_dataset.c:1290:12: error: 'atp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
[GCC 4.9.2 -Ofast]
u8_textprep.c:1310:9: error: 'tc[3ul]' may be used uninitialized in this function [-Werror=maybe-uninitialized]
u8_textprep.c:177:23: error: 'u8t[0ul]' may be used uninitialized in this function [-Werror=maybe-uninitialized]
dsl_dataset.c:2089:37: error: ‘hds’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
dsl_dataset.c:3216:2: error: ‘ds’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
dsl_dataset.c:1591:2: error: ‘ds’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
dsl_dataset.c:3341:2: error: ‘ds’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
vdev_raidz.c:1153:8: error: 'dcount[2]' may be used uninitialized in this function [-Werror=maybe-uninitialized]
vdev_raidz.c:1167:17: error: 'dst[2]' may be used uninitialized in this function [-Werror=maybe-uninitialized]
kernel.c:1005:2: error: ‘resid’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
libzfs_dataset.c:2826:8: error: ‘val’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
libzfs_dataset.c:3056:35: error: ‘val’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
libzfs_dataset.c:1584:13: error: ‘val’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
libzfs_dataset.c:3056:35: error: ‘val’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
libzfs_dataset.c:1792:66: error: ‘val’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
libzfs_dataset.c:3986:35: error: ‘val’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
[GCC 6.1.1]
Resolved in PR #4907
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4937
Builds off of 1eeb4562 (Implementation of AVX2 optimized Fletcher-4)
This commit adds another implementation of the Fletcher-4 algorithm.
It is automatically selected at module load if it benchmarks higher
than all other available implementations.
The module benchmark was also amended to analyze the performance of
the byteswap-ed version of Fletcher-4, as well as the non-byteswaped
version. The average performance of the two is used to select the
the fastest implementation available on the host system.
Adds a pair of fields to an existing zcommon module parameter:
- zfs_fletcher_4_impl (str)
"sse2" - new SSE2 implementation if available
"ssse3" - new SSSE3 implementation if available
Signed-off-by: Tyler J. Stachecki <stachecki.tyler@gmail.com>
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4789
The fletcher_4_native() and fletcher_4_byteswap() functions may only
safely use the vectorized implementations when the buffer is 128-bit
aligned. This is because both the AVX2 and SSE implementations process
four 32-bit words per iterations. Fallback to the scalar implementation
which only processes a single 32-bit word for unaligned buffers.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Issue #4330
New functionality:
- Preserves existing scalar implementation.
- Adds AVX2 optimized Fletcher-4 computation.
- Fastest routines selected on module load (benchmark).
- Test case for Fletcher-4 added to ztest.
New zcommon module parameters:
- zfs_fletcher_4_impl (str): selects the implementation to use.
"fastest" - use the fastest version available
"cycle" - cycle trough all available impl for ztest
"scalar" - use the original version
"avx2" - new AVX2 implementation if available
Performance comparison (Intel i7 CPU, 1MB data buffers):
- Scalar: 4216 MB/s
- AVX2: 14499 MB/s
See contents of `/sys/module/zcommon/parameters/zfs_fletcher_4_impl`
to get list of supported values. If an implementation is not supported
on the system, it will not be shown. Currently selected option is
enclosed in `[]`.
Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4330
Romain Dolbeau
Gvozden Neskovic
Tony Hutter
Tyler J. Stachecki
Brian Behlendorf
Jinshan Xiong