Hi Niklas, Às 4:25 PM de 12/12/2016, Niklas Cassel escreveu: > > > On 12/12/2016 11:19 AM, Joao Pinto wrote: >> Hi, >> >> Às 1:44 AM de 12/10/2016, Florian Fainelli escreveu: >>> Le 12/09/16 à 16:16, Andy Shevchenko a écrit : >>>> On Sat, Dec 10, 2016 at 12:52 AM, Florian Fainelli <f.faine...@gmail.com> >>>> wrote:
(snip...) >> >> @Rabin Vincent: Hi Rabin. Since Axis is more familiar with the synopsys/*qos* >> driver would it be possible for you to make an initial analysis of what has >> to >> be merged into Stmmac? This way the development would speed-up. > > I can answer that question. > > I've sent out 12 patches to the stmmac driver > (all patches are included in the current net-next tree), > with these patches the stmmac driver works properly on Axis hardware > (we use Synopsys GMAC 4.10a synthesized with multiple TX queues). > stmmac's DT binding has also been extended with properties that > existed in DWC EQoS's DT binding, such as no-pbl-x8, txpbl, rxpbl. > > Since we have no problem updating the DTB together with the kernel, > we will simply move to using the start using the stmmac driver, > with stmmac's DT binding. > > However, I've noticed that NVIDIA has extended the DWC EQoS DT binding, > I don't how easy it would be for them to switch to stmmac's DT binding. > (Adding Stephen Warren to CC.) > > The reset sequence that Lars Persson was worried about is not an issue > with the stmmac driver. Great! So you saying that stmmac works great with AXIS hardware and no need to merge specific code from AXIS' *qos* driver? > > > > > There are some performance problems with the stmmac driver though: > > When running iperf3 with 3 streams: > iperf3 -c 192.168.0.90 -P 3 -t 30 > iperf3 -c 192.168.0.90 -P 3 -t 30 -R > > I get really bad fairness between the streams. > > This appears to be an issue with how TX IRQ coalescing is implemented in > stmmac. > Disabling TX IRQ coalescing in the stmmac driver makes the problem go away. > We have a local patch that implements TX IRQ coalescing in the dwceqos driver, > and we don't see the same problem. > > Also netperf TCP_RR and UDP_RR gives really bad results compared to the > dwceqos driver (without IRQ coalescing). > 2000 transactions/sec vs 9000 transactions/sec. > Turning TX IRQ coalescing off and RX interrupt watchdog off in stmmac > gives the same performance. I guess it's a trade off, low CPU usage > vs low latency, so I don't know how important TCP_RR/UDP_RR really is. > > The best thing would be to get a good working TX IRQ coalesce > implementation with HR timers in stmmac. > Perhaps it should also be investigated if the RX interrupt watchdog > timeout should have a lower default value. > > > >> >> Thanks to all. >> >> Joao >
