Re: [RFC PATCH 0/6] Convert all tasklets to workqueues

From: Steven Rostedt
Date: Thu Jun 28 2007 - 11:54:50 EST



On Thu, 28 Jun 2007, Alexey Kuznetsov wrote:
> > the context-switch argument i'll believe if i see numbers. You'll
> > probably need in excess of tens of thousands of irqs/sec to even be able
> > to measure its overhead. (workqueues are driven by nice kernel threads
> > so there's no TLB overhead, etc.)
>
> It was authors of the patch who were supposed to give some numbers,
> at least one or two, just to prove the concept. :-)

The problem is that we don't have the hardware that uses tasklets in
critical ways. My original patch series had a debug print in every
function (tasklet_schedule and friends). I got a few scattered prints on
all my boxes but no flooding of prints. So I can't show that this will
hurt, because on my boxes it does not.

>
> You could set realtime prioriry by default, not a poor nice -5.
> If some network adapters were killed just because I run some task
> with nice --22, it would be just ridiculous.

This is my fault to the patch series. I compelety forgot to up the prio.
My next series will include a change where the tasklet work queue will run
at something like prio FIFO 98 (or maybe 99?)

This is a bit embarrassing that I forgot to do this, since I'm a
real-time developer ;-)

-- Steve

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