> I'm assuming you have a UHCI hardware Host Controller; if so, have you > tried both the usb-uhci and uhci kernel drivers? One may be faster...
It's UHCI. I just tried uhci instead of usb-uhci and this didn't change speed of syncSubmit on the control pipe. > > >(probably 3 ms or less on average). It's quite important for applications > >that use control pipe a lot: I2C read is 4 syncSubmit calls so it'll take > >a second to get a telemetry packet of 20 bytes. I don't know how to use > >composite IRPs with asyncSubmit since you have to alternate reads and > >writes on the control pipe with program logic in the middle that depends > >on results of these reads (checking for I2C ready). > > yeah, that's not possible (now). The list has to be basically fixed-data. > I think it would be harder than it's worth to do dynamic-data submission, > where one data packet depends on the previous results...it's easier just > to let the user parse and submit another... > > as far as your time calculations, are you sure than 4 syncSubmits > (assuming they are 12ms) adds up to 1 second...? Isn't 4*12ms = 48ms? > I agree that if Windows is 3ms, 4*3ms = 12ms which is much better, but > still 50ms is pretty fast...at least, fast enough for now...? Does your > application see performance problems because of it? It's 48ms for one data byte over I2C and 48x20=960ms for a complete packet of 20 bytes that the app has to exchange with the device (I wrote "up to a second"). There are a couple of tricks to speed things up but it'll still be slow and will affect perforamnce of the system. The point I'm trying to make is that such things really matter when an application is using syncSubmit a lot and has certain latency requirements. It'll be great to speed things up if possible... I'll try the fix for the memory leak (published in another thread). > > Thanks! > Thank you! Boris > -- > Dan Streetman > [EMAIL PROTECTED] > --------------------- > 186,272 miles per second: > It isn't just a good idea, it's the law! > > > > ------------------------------------------------------- > This sf.net email is sponsored by: See the NEW Palm > Tungsten T handheld. Power & Color in a compact size! > http://ads.sourceforge.net/cgi-bin/redirect.pl?palm0001en > _______________________________________________ > javax-usb-devel mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/javax-usb-devel > ------------------------------------------------------- This sf.net email is sponsored by: See the NEW Palm Tungsten T handheld. Power & Color in a compact size! http://ads.sourceforge.net/cgi-bin/redirect.pl?palm0001en _______________________________________________ javax-usb-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/javax-usb-devel
