multithreading - OpenCL program running on CPU -

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i want compare performance of single-core cpu , multi-core cpu. wrote program , let iterate 1000 times on single-core cpu see running time. in multi-core case, used opencl launch kernel code same inside iteration in first case.

considered multi-core run 8 concurrent threads, theoretically, running time of multi-core case should above t(single-core)/8. results t(multi-core) 1/20 of t(single-core).

i wonder why happen? did opencl compiler optimization multi-core cpu ?

if single core code scalar, chances opencl runtime used sse or avx , multiplier.


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