[dan-robertson]

Why is the rtt measured here on canon lake so asymmetric? I would have expected symmetry along the leading diagonal.

[yvdriess]

Speculation, but could it be because of a ring topology?

[jeffbee]

And why is core 0 magical on that machine?

[jcranmer]

IIRC, core 0 is the one that tends to service processor interrupts, which may mean that the data is unusually noisy in a way that tends to underestimate the RTT latency time.

[jeffbee]

There’s a similar weird artifact at index 64.

[innocenat]

Core 64 is the hyper-threaded pair of core 0.

[jeffbee]

Not on that machine. That would only be true on a 128-thread system, but this one has 96 threads.