Re:Improving Linux networking performance
by donavanm on Friday January 23, 2015 @06:20PM
(#8938007)
Pretty much everything has supported 9k jumbos for over a decade. The internets mostly 1.5k MTU, but you normally arent doing multi gigabit streams over public connectivity. The other argument is TSO. Your kernels probably writing a 64K "packet" to the NIC driver. When segmentation etc is handled by the hardware why do you care about the MSS? On the network device side the SerDes are the issue. And were already running parallel lanes there; 40 is 4x 10 lanes and 100 is 4x 25 lanes. Why not 10x 100 in a couple years?
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Re:Improving Linux networking performance
by nitrogen on Friday January 23, 2015 @11:39PM
(#8938845)
When segmentation etc is handled by the hardware why do you care about the MSS?
Because of Ethernet's mandatory minimum inter-packet spacing.
Re:Improving Linux networking performance
by donavanm on Saturday January 24, 2015 @12:59AM
(#8938942)
Ok... So looking at IFG as 96 bits or 12 bytes of "overhead" thats 0.8% or 0.13% for 1.5k and 9k frames. Why do I care about 0.67% of throughput? And pretty much all silicon in over a decade does line rate at 1k anyways. Or if its latency a hypothetical higher clocked lane would be something like 1ns instead of ~3ns per frame? Thats the difference between 2 clock cycles and 6 cycles of latency.
So what is your shorter/faster ifg buying in practice.