Thanks for trying this out Dave! > With byte queue limits at mtu*3 + the SFQ qdisc, latency under load > can be hammered > down below 6ms when running at a 100Mbit line rate. No CBQ needed. > I'm hoping that we didn't have to set the BQL max_limit. I would guess that this might indicate some periodic spikes in interrupt latency (BQL will increase limit aggressively in that case). You might want to try adjusting the hold_time to a lower value. Also, disabling TSO might lower the limit.
Without lowering the max_limit, what values so you see for limit and inflight? If you set min_limit to a really big number (effectively turn of BQL), what does inflight grow to? > Anyway, script could use improvement, and I'm busily patching BQL into > the ag71xx driver as I write. > Cool, I look forward to those results! > Sorry it's taken me so long to get to this since your bufferbloat > talks at linux plumbers. APPLAUSE. > It's looking like BQL + SFQ is an effective means of improving > fairness and reducing latency on drivers > that can support it. Even if they have large tx rings that the > hardware demands. > Great. I actually got back to looking at this a little last week. AFAICT the overhead of BQL is < 1% CPU and throughput (still need more testing to verify that). There are some (very) minor performance improvements that might be possible, but I don't have any major modifications pending at this point. _______________________________________________ Bloat mailing list [email protected] https://lists.bufferbloat.net/listinfo/bloat
