hi, On Tue, Jun 14, 2011 at 06:06:16PM +0800, Bob Liu wrote: > > On Tue, Jun 14, 2011 at 05:52:23PM +0800, Aaron Wu wrote: > >> On Tue, Jun 14, 2011 at 5:39 PM, Felipe Balbi <balbi@xxxxxx> wrote: > >> > Hi, > >> > > >> > On Tue, Jun 14, 2011 at 05:34:09PM +0800, Aaron Wu wrote: > >> >> Since the wifi card we are using is of the USB interface. We tried on > >> >> two diffrent USB controllers, looks like the ISP1362 works OK and > >> >> problems happens only on MUSB controller. For both USB controllers we > >> >> are using the same kernel version and USB wifi card. > >> > > >> > Yeah, USB host has quite some performance issues to be fixed. To start > >> > with, it uses only DMA Mode0, which is bound to packet boundaries. BTW, > >> > which embedded platform are you using ? Which SoC ? > >> > > >> > >> Hi balbi, > >> Thanks for the quick reply. Our concern is the priority capability, > >> current problems is, the network data packge should have been > >> prioritized in the IPV4 stack itself, by IP_TOS option as mentioned, > >> we are just curious why the priority looks like to have something to > >> do with the USB controller, I mean by experiment the prioritization > >> works well on some USB controllers like that on a X86 PC and ISP1362, > >> but does not work on MUSB. > >> > >> We are using PIO mode on Blackfin. Performance is not our concern at > >> this moment, actually the MUSB has better throughput performance than > >> the ISP1362, but the prioritization works on 1362. On the 1362 > >> controller, the second iperf session(high priority) always take up a > >> large bandwidth while the other two low priority session get only a > >> little in the test as expected. On MUSB, we see no priority for the > >> second session, it drops greatly as if it has the same low priority as > >> the first and third session. > > > > Well, I can't answer that question, specially since it's on Blackfin. > > > > Maybe Mike can help > > I have looked into that problem and have no idea. So i asked Aaron to > email to maillist for some help. > > Is anyone can help verify this problem on other musb platform? Thanks. yeah, but if the problem isn't throughput, I don't see how MUSB could be to blame here. The network priority should have been handled by IP layer and the controller shouldn't matter, right ? -- balbi
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