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

[Bill Davidsen]

Ingo Molnar wrote:
> * Lee Revell <rlrevell@xxxxxxxxxxx> wrote:
>
>
> > Yes, on a server you would probably disable threading for the disk and
> > network IRQs (the VP patch lets you set this via /proc).  This feature
> > effectively gives you IPLs on Linux, albeit only two of them. [...]
>
>
> nono, this has no relation to IPLs. IPLs are a pretty crude hack to
> implement exclusion on a very (and too) broad level. IRQ threading is a
> way to serialize hardirq contexts into a process context and to make
> them schedulable and preemptable. It basically 'flattens out' all the
> hardirq nesting (and parallelism) that may happen on a default kernel
> and together with softirq 'flattening' it creates a deterministic
> execution environment.
>
> 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.

Okay, I'll be the one to ask... what overload of the IPL acronym are you 
using here? I asked google and several jargon files, and they all say 
that IPL (initial program load) is IBMspeak for cold boot. Somehow I 
don't think that's what you mean here.

--
   -bill davidsen (davidsen@xxxxxxx)
"The secret to procrastination is to put things off until the
 last possible moment - but no longer"  -me
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