C11/C++11 weak memory benchmarks

Question

Can anyone point to benchmark results comparing performance of C11/C++11 code using relaxed atomic operations (particularly memory_order_release and memory_order_acquire, but also memory_order_consume and memory_order_relaxed) versus the default memory_order_seq_cst? All architectures are of interest. Thanks in advance.

Answer 1

I did a bit of benchmarking on ARMv7, see https://github.com/reinhrst/ARMBarriers for the report, the slides for my talk at EuroLLVM, and the seqlock code I used.

Short story: in the seqlock code, the Acquire/Release function was about 40% faster than the sequentially consistent version.