Alan Cox writes: > > On Sun, 15 Nov 1998, Olaf Meyer wrote: > > > > > I'm modfying the WaveLAN ethernet device driver in order > > > to get some Quality of Service guarantees. To this end > > > I have to control the timing when packets get transmitted. > > > I therefore cannot transmit packets when net_bh wants > > > to transmit them. > > The first question of course is _why_ is he putting QoS guarantees at > the device level not higher up as 2.1.x does Well, I'm doing it at the device level, because we want to get pretty tight bounds on latency and therefore want to eliminate collisions at the device level by implementing some kind of token bus scheme ontop of the CSMA/CA protocol. We also probably do not want to use it directly with TCP/IP but rather with some protocols we'll develop on our own. The 10ms software timer resolution are not going to be enough, so we're currently also using the UTIME patch from the University of Kansas (see http://hegel.ittc.ukans.edu/projects/utime ), which increases the software timer resolution to the microsecond range without increasing the overhead significantly. I would be glad to have some pointers to the QoS stuff which is new with the 2.1 kernels, to see if iy might be usefull for us :-) Are there more docs available besides the documentation in the source files in net/sched? Thanks, Olaf - To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to [EMAIL PROTECTED]
