Re: [PATCH 1/3] Separate IRQ-stacks from 4K-stacks option

[Timothy Miller]

Ingo Molnar wrote:

> it is not intended for servers, due to the overhead of redirection. It's
> for realtime workloads and for latency-sensitive audio desktop
> workloads. For servers and normal desktops the current IRQ and softirq
> model is pretty OK.


I commented previously about the preemption allowing the kernel to keep 
more resources busy.  So if you have 6 disk controllers and 4 NICs, the 
preemption can allow the kernel to keep more of them busier at the same 
time, while without preemption, one resource might get starved while 
non-preemptable code is servicing another.

This makes the overhead very much worth it.

Are there test results which demonstrate that this theory doesn't apply 
practically to real-world server loads?

I would expect a very busy server to be helped by this in a noticable 
way, but then I am often short-sighted.  :)

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