On Sun, Dec 28, 2014 at 1:48 PM, Beniamino Galvani <b.galv...@gmail.com> wrote: > On Sun, Dec 28, 2014 at 08:25:40AM -0800, Dave Taht wrote: >> On Sun, Dec 28, 2014 at 6:57 AM, Beniamino Galvani <b.galv...@gmail.com> >> wrote: >> > Add support for Byte Queue Limits to the STMicro MAC driver. >> >> Thank you! >> >> > Tested on a Amlogic S805 Cortex-A5 board, where the use of BQL >> > slightly decreases the ping latency from ~10ms to ~3ms when the >> > 100Mbps link is saturated by TCP streams. No difference is >> > observed at 1Gbps. >> >> I see the plural. With TSQ in place it is hard (without something like >> the rrul test driving multiple streams) to drive a driver to >> saturation with small numbers of flows. This was with pfifo_fast, not >> sch_fq, at 100mbit? > > Hi Dave, > > yes, this was with pfifo_fast and I used 4 iperf TCP streams. The total > throughput didn't seem to increase adding more streams.
>> >> Can this board actually drive a full gigabit in the first place? Until >> now most of the low end arm boards I have seen only came with >> a 100mbit mac, and the gig ones lacking offloads seemed to peak >> out at about 600mbit. > > I measured a throughput of 650mbit in rx and 600mbit in tx. You might want to try the rrul test which tests both directions and latency at the same time. In my case I have been trying to find a low-cost chip that could do soft rate limiting (htb) + fq_codel at up to 300mbit/sec, as that is about the peak speed we will be getting from cable modems, and these are horribly overbuffered, at these speeds too, with 1.2sec of bidirectional latency observed at 120mbit/12mbit. I'm open to crazy ideas like trying to find a use for the gpu, etc, to get there. > >> >> Under my christmas tree landed a quad core A5 (odroid-c1), also an >> xgene and zedboard - both of the latter are a-needing BQL, >> and I haven't booted the udroid yet. Hopefully it is the >> same driver you just improved. > > I'm using the odroid-c1 too, with this tree based on the recent > Amlogic mainline work: > > https://github.com/bengal/linux/tree/meson8b Oh, cool, thx! > Unfortunately at the moment the support for the board is very basic > (for example, SMP is not working yet) but it's enough to do some NIC > tests. Good to know. Have you looked at xmit_more yet? http://lwn.net/Articles/615238/ > Beniamino -- Dave Täht http://www.bufferbloat.net/projects/bloat/wiki/Upcoming_Talks -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/