Re: [Q]: Linux and real device drivers

Alan Cox (alan@lxorguk.ukuu.org.uk)
Wed, 22 Sep 1999 00:02:53 +0100 (BST)


> on a CPU while new IRQs come in on the other processor. It can be better for
> cache as well, since interrupts do less work and are therefore less
> disruptive of the instruction and data cache. This would help cache on both
> SMP and UP systems.

Oh joyous - you want to play pingpong with the cache across the irq and
task execution side. Other OS's actually schedule stuff aggressively onto
the same CPU to avoid that.

> When you structure things this way, it also tends to minimize the amount of
> driver code requiring that you disable interrupts. No data structures other
> than the semaphore that are accessed from interrupt, so you don't have to
> block interrupts when doing mutual exclusion.

Granted - its _very_ good for hard real time. It isnt so hot for throughput

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