Re: mlnx_tune does not detect the BIOS I/O non-posted prefetch settings?

Hi,

First of all, I'm glad to hear you are using mlnx_tune and I hope you find it at least a little bit helpful.

For the issue above, I agree the behavior isn't perfect but I would like to explain a few points:

1. For most (if not all) OS, it is next to impossible to query for the I/O non-posted prefetch value. This is why I choose to prompt the user of a possible issue (note the 'might' in the message).
2. The issue with I/O non-posted prefetch is only relevant when trying to run traffic at rates higher than 150Gb/s (bidirectional). This is only relevant for EDR, FDR (dualport over x16 PCI), 100GbE and 40/50/56GbE (dualport over x16 PCI). This is why the warning only shows for x16 devices. It is simply impossible to get high enough rate with shorter PCI width.

I hope this answers your concern. If not, I would be happy to hear your feedback and improve mlnx_tune.