Current RVV x280 target depends on vlen=512-bits for Level 3 operations.
Commit adds generic target that supports vlen=128-bits.
New target uses the same scalable kernels as x280 for Level 1&2 operations, and autogenerated kernels for Level 3 operations.
Functional correctness of Level 3 operations tested on vlen=128-bits using QEMU v8.1.1 for ctests and BLAS-Tester.
* fix multiple numerical stability and corner case issues
* add a script to generate arbitrary gemm kernel shapes
* add a generic zvl256b target to demonstrate large gemm kernel unrolls
This adds an SVE implementation to sdot/ddot when available, falling back to the previous Advanced SIMD kernel where there's no SVE implementation for the kernel.
All the targets were essentially treating `dot_thunderx2t99.c` as the Advanced SIMD implementation so I've renamed it to better fit with the feature detection.
Removing y avoids cache effects (if y is the size of the L1 cache, the
main array x is removed from it).
Moving init and timing out of the loop makes the scal benchmark behave like
the gemm benchmark, and allows higher accuracy for smaller test cases since
the loop overhead is much smaller than the timing overhead.
Example:
OPENBLAS_LOOPS=10000 ./dscal.goto 1024 8192 1024
on AMD Zen2 (7532) with 32k (4k doubles) L1 cache per core.
Before
From : 1024 To : 8192 Step = 1024 Inc_x = 1 Inc_y = 1 Loops = 10000
SIZE Flops
1024 : 5627.08 MFlops 0.000000 sec
2048 : 5907.34 MFlops 0.000000 sec
3072 : 5553.30 MFlops 0.000001 sec
4096 : 5446.38 MFlops 0.000001 sec
5120 : 5504.61 MFlops 0.000001 sec
6144 : 5501.80 MFlops 0.000001 sec
7168 : 5547.43 MFlops 0.000001 sec
8192 : 5548.46 MFlops 0.000001 sec
After
From : 1024 To : 8192 Step = 1024 Inc_x = 1 Inc_y = 1 Loops = 10000
SIZE Flops
1024 : 6310.28 MFlops 0.000000 sec
2048 : 6396.29 MFlops 0.000000 sec
3072 : 6439.14 MFlops 0.000000 sec
4096 : 6327.14 MFlops 0.000001 sec
5120 : 5628.24 MFlops 0.000001 sec
6144 : 5616.41 MFlops 0.000001 sec
7168 : 5553.13 MFlops 0.000001 sec
8192 : 5600.88 MFlops 0.000001 sec
We can see the L1->L2 switchover point is now where it should be, and the
number of flops for L1 is more accurate.
The existing kernel was issuing extra instructions to organise the arguments into the same registers they would usually be in and similarly to put the result into the appropriate register.
This has an impact on smaller sized dots and seemed like a quick fix
Octavian Maghiar
Martin Kroeker
ZhengSh
Heller Zheng
Zhang Xianyi
Zhang Xianyi
Sergei Lewis
Chris Sidebottom
Bart Oldeman