On Thu, Feb 28, 2002 at 01:00:59AM +0100, Oliver Neukum wrote: > On Thursday 28 February 2002 00:29, Greg KH wrote: > > On Thu, Feb 28, 2002 at 12:18:41AM +0100, Oliver Neukum wrote: > > > Why ? > > > If the pool is formed by allocating the memory for urbs in chunks > > > the positive effect on TLB and cache is there whether the allocation > > > in the drivers is dynamic or not. > > > In fact, could we use the slab cache as is ? > > > > We could. But the point I was trying to make is that USB drivers only > > create urbs very infrequently (on device insertion), so any speed > > benefits are quite limited (we don't really care about speed when > > initializing a device.) > > I must disagree partially. > The effect on TLB usage is the same whether the allocation > is dynamic or not. Furthermore we should plan for usb2.0 > devices where it might be become noticeable.
I agree. > AFAIK a Pentium class CPU has 16 entries for large pages. > This means that we can cache TLB entries for 64MB. > For my machine this makes a miss probability of 3/4 > with randomly distributed urbs. > If we can't use large pages things become nasty. > USB on a 486 ? Think USB on uCLinux (it's true) :) greg k-h _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
