This is a collection of simple streaming kernels for teaching purposes. It is heavily inspired by John McCalpin's https://www.cs.virginia.edu/stream/.
It contains the following streaming kernels with corresponding data access pattern (Notation: S - store, L - load, WA - write allocate):
- init (S1, WA): Initilize an array. Store only.
- sum (L1): Vector reduction. Load only.
- copy (L1, S1, WA): Classic memcopy.
- update (L1, S1): Update a vector. Also load + store but without write allocate.
- triad (L2, S1, WA): Stream triad -
a = b + b * scalar
. - daxpy (L2, S1): Daxpy -
a = a + b * scalar
. - striad (L3, S1, WA): Schoenauer triad -
a = b + c * d
. - sdaxpy (L3, S1): Schoenauer triad without write allocate -
a = a + b * c
.
- Configure the toolchain to use in the
Makefile
:
TAG = GCC # Supported GCC, CLANG, ICC
- Review the flags for toolchain in the corresponding included file, e.g.
include_GCC.mk
. OpenMP is disabled per default, you can enable it by uncommenting the OpenMP flag:
OPENMP = -fopenmp
- Build with:
make
You can build multiple toolchains in the same directory, but notice that the Makefile is only acting on the one currently set.
Intermediate build results are located in the <TOOLCHAIN>
directory.
- Clean up with:
make clean
to clean intermediate build results.
make distclean
to clean intermediate build results and binary.
- (Optional) Generate assembler:
make asm
The assembler files will also be located in the <TOOLCHAIN>
directory.
To run the benchmark call:
./bwBench-<TOOLCHAIN>
The benchmark will output the results similar to the stream benchmark. Results are validated. For threaded execution it is recommended to control thread affinity.
We recommend to use likwid-pin for benchmarking:
likwid-pin -c 0-3 ./bwbench-GCC
Example output for threaded execution:
-------------------------------------------------------------
[pthread wrapper]
[pthread wrapper] MAIN -> 0
[pthread wrapper] PIN_MASK: 0->1 1->2 2->3
[pthread wrapper] SKIP MASK: 0x0
threadid 140271463495424 -> core 1 - OK
threadid 140271455102720 -> core 2 - OK
threadid 140271446710016 -> core 3 - OK
OpenMP enabled, running with 4 threads
-------------------------------------------------------------
Function Rate (MB/s) Avg time Min time Max time
Init: 14681.5000 0.0110 0.0109 0.0111
Sum: 20634.9290 0.0079 0.0078 0.0082
Copy: 18822.2827 0.0172 0.0170 0.0176
Update: 28135.9717 0.0115 0.0114 0.0117
Triad: 19263.0634 0.0253 0.0249 0.0268
Daxpy: 26718.1377 0.0182 0.0180 0.0187
STriad: 21229.4470 0.0305 0.0301 0.0313
SDaxpy: 26714.3897 0.0243 0.0240 0.0253
-------------------------------------------------------------
Solution Validates