On Tue, Sep 15, 2015 at 03:04:58PM -0400, Alan Stern wrote: > On Tue, 15 Sep 2015, Felipe Balbi wrote: > > > Instead of allowing a range of 2 to 4 requests, > > let's allow the user choose up to 32 requests > > as that will give us a better chance of keeping > > controller busy. > > > > We still maintain default of 2 so users shouldn't > > be affected. > > Was this change inspired by testing? What were the test results? yeah, this one yeah. With the changes to dwc3 above, I have a much better chance of keeping the controller's queue busy with a deeper usb_request queue length. That means that we will be avoid XferComplete and a subsequent XferNotReady which translates directly to less NAK/NYET handshakes in the bus. Also less POLLs. I can send you sniffer traces if you want, but you'd have to make an account with Total phase to download the Data Center SW to be able to read it. -- balbi
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