From: Ingo M. <mi...@el...> - 2002-08-30 11:47:07
|
On Fri, 30 Aug 2002, Keith Whitwell wrote: > The radeon cards can send me back IRQ's at helpful points in the command > stream. I think I'd like to use these for most synchronization, however > some cleverness may be required to reduce the total number of irq's > generated. > > Is there a threshold say in irqs/second beyond which it makes more sense > to busy wait? what is the basic command completion notification method of the hardware? is it basically a pipeline (or ring) of commands and a status bit in some (mmap-shared) register, which is polled by userspace to see whether more commands can be posted? Or do you poll the commands directly? plus the hardware has the ability to also send a notification interrupt if the command queue gets empty? [or half empty - or some threshold?] and what is the typical latency of commands (as executed by the GX hw) - and what is the maximum latency of commands that can occur? also, most of the looping done here is not due to some other process taking the 'DRI lock', correct? Ingo |