Messages in this thread | | | Date | Fri, 27 Feb 2004 08:14:45 +0100 | From | Arjan van de Ven <> | Subject | Re: Why no interrupt priorities? |
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On Thu, Feb 26, 2004 at 02:21:34PM -0800, Mark Gross wrote: > > hardware IRQ priorities are useless for the linux model. In linux, the > > hardirq runs *very* briefly and then lets the softirq context do the > > longer taking work. hardware irq priorities then don't matter really > > because the hardirq's are hardly ever interrupted really, and when they > > are they cause a performance *loss* due to cache trashing. The latency > > added by waiting briefly is going to be really really short for any sane > > hardware. > > Keep in mind the context is Linux running on non-sane hardware, sloooow CPUs,
50Mhz is already really really fast in this context.
> latency sensitive small io buffers etc. Losing system wide throughput to have > the hardware codec not be starved is a happy trade off to make.
The point I tried to make was that it would INCREASE latency. Unless you have misdesigned device drivers, which is something that is fixable :) [unhandled content-type:application/pgp-signature] | |