Re: libusb performance on 8.1
On 28/01/2011, at 19:18, Hans Petter Selasky wrote: > There are some hard limits in the libusb source code. Just search for 16K in > decimal. In the kernel the limit is bigger and I guess you don't need to > change anything there. Ahh OK thanks, I was looking in the kernel. > >> Is it possible to change the amount that is buffered? This is a specialised >> application so a custom kernel is no problem. Even a hint in the right >> direction would be greatly appreciated :) > >> >>> You could also try an XHCI controller, because the BULK buffering is done >>> differently there. >> >> OK thanks, I'll try that too. > > --HPS > -- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C ___ freebsd-usb@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
Re: libusb performance on 8.1
On Friday 28 January 2011 09:42:57 Daniel O'Connor wrote: > On 28/01/2011, at 18:28, Hans Petter Selasky wrote: > > For this kind of applications ISOCHRONOUS transfers should be used. Then > > you can have a double buffer guard in the range 1-56ms, regardless of > > the buffer size the hardware uses. > > Hmm, OK, I will have a look at changing it, although it is a bit of a pain > because you can't stall an ISO EP and I'm using stall to indicate an > error. Hi, There are some hard limits in the libusb source code. Just search for 16K in decimal. In the kernel the limit is bigger and I guess you don't need to change anything there. > Is it possible to change the amount that is buffered? This is a specialised > application so a custom kernel is no problem. Even a hint in the right > direction would be greatly appreciated :) > > > You could also try an XHCI controller, because the BULK buffering is done > > differently there. > > OK thanks, I'll try that too. --HPS ___ freebsd-usb@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
Re: libusb performance on 8.1
On 28/01/2011, at 18:28, Hans Petter Selasky wrote: > For this kind of applications ISOCHRONOUS transfers should be used. Then you > can have a double buffer guard in the range 1-56ms, regardless of the buffer > size the hardware uses. Hmm, OK, I will have a look at changing it, although it is a bit of a pain because you can't stall an ISO EP and I'm using stall to indicate an error. Is it possible to change the amount that is buffered? This is a specialised application so a custom kernel is no problem. Even a hint in the right direction would be greatly appreciated :) > You could also try an XHCI controller, because the BULK buffering is done > differently there. OK thanks, I'll try that too. > >> I obviously don't need any more >> throughput, however my application is very sensitive to latency, as I am >> reading out of a fairly small FIFO and if it fills up my entire run has to >> be aborted. > > > > --HPS > -- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C ___ freebsd-usb@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
