On Fri, 2 Mar 2007, Nick Piggin wrote: > > You do not have to deal with TLB entries if you do buffered I/O. > > Where does the data come from?
>From the I/O controller and from the application. > > We currently have problems with the kernel limits of 128 SG > > entries but the fundamental issue is that we can only do 2 Meg of I/O in > > one go given the default limits of the block layer. Typically the number > > of hardware SG entrie is also limited. We never will be able to put a > > Seems like changing the default limits would be the easiest way to > fix it then? This would only be a temporary fix pushing the limits to the double or so? > As far as hardware limits go, I don't think you need to scale that > number linearly with the amount of memory you have, or even with the > IO throughput. You should reach a point where your command overhead > is amortised sufficiently, and the controller will be pipelining the > commands. Amortized? The controller still would have to hunt down the 4kb page pieces that we have to feed him right now. Result: Huge scatter gather lists that may themselves create issues with higher page order. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
