* Brandeburg, Jesse | 2023-12-05 18:58:37 [+0000]:
Hey Jesse
We thought it might be a useful start to figure out a good set of benchmarks to demonstrate "power vs networking" problems. I have a couple in mind right away. One is "system is sleeping but I'm trying to run a latency sensitive workload and the latency sucks" Two is "system is sleeping and my single-threaded bulk throughput benchmark (netperf/iperf2/neper/etc) shows a lot of retransmits and / or receiver drops"
The first is a good - but rather unreasonable, isn't it? RT guys setting max_cstate to 1 or so to guarantee a low latency, deterministic RT behavior. I think that if low latency is the ultimate goal, compromises must inevitably be made in the PM domain.
The second it don't get (e.g.): - CPU is in idle state C10 - NIC wakeup and interrupt CPU interrupt controller - CPU C10 -> C0 - softirq and packet will be processed until delivered to netperf/iperf2/neper
Where do the retransmits/drops occur here? Sure C10 -> C0 takes some wakeup penalty, but no drop.
Jesse, I wonder if the benchmarks lead to much? Can we use them to make measurements that are comparable? What do you want to achieve with the benchmarks? Sorry for asking these questions! ;-)
hgn