UCT/IB: Use relaxed ordering for Intel Emerald Rapids CPUs #10955
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What?
Register memory with relaxed ordering flag on Intel Emerald Rapids.
Why?
Without
IBV_ACCESS_RELAXED_ORDERING, traffic can take different PCIe path with BW ~16GB/s instead of >40GB/s.Workaround without this PR:
UCX_IB_PCI_RELAXED_ORDERING=yCheck CPU:
ucx_info -s | grep CPUInternal: 5572179