Luke Gorrie

Relatedly: Nathan Owens pointed out to me via Twitter that the sexy Broadcom Tomahawk 32x100G switches only do line-rate with >= 250B packets. Seems to be confirmed on [ipspace.net](http://blog.ipspace.net/2015/12/broadcom-tomahawk-101.html).

Here are some public performance numbers from Mellanox: https://www.mellanox.com/blog/2016/06/performance-beyond-numbers-stephen-curry-style-server-io/ The headlines there are line-rate 64B with 25G NIC and 74.4 Mpps max on 100G. (I am told they have squeezed...

I tested the ConnectX-4 with every packet size 60..1500 and at both 3.5 GHz and 2.0 GHz.  Whaddayareckon?

Good question. It _looks_ like the size of each packet is effectively being rounded up to a multiple of 64. I wonder what would cause this? Suspects to eliminate: -...

### DMA/PCIe I would really like to extend our PMU support to also track "uncore" counters like PCIe/RAM/NUMA activity. This way we could include all of those values in the...

@fmadio Yes, this sounds like the most promising line of inquiry now: Can we explain the performance here, including the plateau every 64B, in terms of the way the memory...

@fmadio Great thoughts, keep 'em coming :). I added a couple of modeled lines based on your suggestions: - _Max 100GbE_ showing the theoretical maximum packet rate, based on the...

This is an absolutely fascinating problem. Can't put it down :). @fmadio Great info! So on the receive path the NIC uses "posted" (fire and forget) PCIe operations to write...

No and maybe, in that order ;-). This is transmit-only (packetblaster) and this root cause is not confirmed yet, just idea de jour. Some more details of the setup over...

The NIC probably has to use posted requests here - read request needs a reply to get the data - but maybe it needs to make twice as many requests...