Date: Thu, 27 Dec 2007 22:18:59 GMT From: Hans Petter Selasky <hselasky@FreeBSD.org> To: Perforce Change Reviews <perforce@FreeBSD.org> Subject: PERFORCE change 131808 for review Message-ID: <200712272218.lBRMIxVT024691@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=131808 Change 131808 by hselasky@hselasky_laptop001 on 2007/12/27 22:18:49 This is the first step towards a currently FreeBSD specific extension to the USB CDC Ethernet protocol. The extension will allow for super high IP transfer rates without the need to copy any data or per-IP-packet interrupts, just like an ordinary ethernet controller. Background: When I started reworking the USB ethernet drivers I noticed that the authors had in mind allocating and queueing multiple USB transfers at a time to boost performance. Unfortunatly that would not have increased any performance, because the USB Host Controller would have had to interrupt for every IP-packet anyway, which would have been the boottlneck. Now that I have implemented something I have called "multi sub-framing" it will finally become realistic to do exactly that, and in a very efficient way using only one USB transfer per direction! Affected files ... .. //depot/projects/usb/src/sys/dev/usb/usb_cdc.h#7 edit Differences ... ==== //depot/projects/usb/src/sys/dev/usb/usb_cdc.h#7 (text+ko) ==== @@ -188,4 +188,13 @@ #define UCDC_MDM_PARITY_ERR 0x20 #define UCDC_MDM_OVERRUN_ERR 0x40 +/* Multi Frame Ethernet Header */ +typedef struct { + uByte bSig0[2]; /* "MF" */ + uDWord dwFramesAhead; + uDWord dwFramesAheadInverse; +} __packed usb_cdc_mf_eth_header_t; + +#define CDC_MF_ETH_HEADER_SIZE 10 /* bytes */ + #endif /* _USB_CDC_H_ */
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