Hi, On Tue, Jun 14, 2011 at 06:20:38PM +0800, Aaron Wu wrote: > >> >> 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 ? > > Yes, it's not about performance. We think the same as you do, it > should be something handled by the IP layer and the controller does > not matter. But expriment shows ISP1362 and X86 PC works, we are > curious how this could happen, wired. Appraciate very much if someone > can shed some light. could you try offlining all cores from the x86 PC except one ? That'll make you closer to the blackfin UP setup. Then see how it behaves. -- balbi
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