RE: My vote against eepro* removal

From: Lee Revell
Date: Fri Jan 20 2006 - 19:44:15 EST


On Fri, 2006-01-20 at 11:19 +0100, kus Kusche Klaus wrote:
> For a non-full preemption kernel, your patch moves the 500 us
> piece of code from kernel to thread context, so it really
> improves things. But is 500 us something to worry about in a
> non-full preemption kernel?

Yes, absolutely. Once exit_mmap (a latency regression which was
introduced in 2.6.14) and rt_run_flush/rt_garbage_collect (which have
always been problematic) are fixed, 500usecs will stick out like a sore
thumb even on a regular PREEMPT kernel.

Also, you should be able to capture this latency in /proc/latency trace
by configuring an -rt kernel with PREEMPT_DESKTOP and hard/softirq
preemption disabled.

Lee

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