Attempting to try out "asynchronous probes" and the current runtime...

[Spirakis, Charles]

Thanks, I'll take a look.

I was planning on looking at oprofile's timing mechanism in general to
see about using a hardware timer instead which would also work for smp
machines. Was hoping to try this as the "easier" test case first, but it
may not have been as easy as I thought :)

-- charles
 

> -----Original Message-----
> From: systemtap-owner@sources.redhat.com 
> [mailto:systemtap-owner@sources.redhat.com] On Behalf Of William Cohen
> Sent: Monday, July 11, 2005 8:28 AM
> To: Spirakis, Charles
> Cc: systemtap@sources.redhat.com
> Subject: Re: Attempting to try out "asynchronous probes" and 
> the current runtime...
> 
> Spirakis, Charles wrote:
> > All --
> > 
> > I'm playing around with an "asynchronous probe" concept and the 
> > current runtime using simple os timers (code is below). Anyone have 
> > experience with task_pt_regs() function? As you can see, 
> I'm trying to 
> > grab the "current" pt_regs in the home of seeing the eip at 
> the time 
> > of the timer interrupt, but the data I get is not what I'd hoped.
> > 
> > This is running on a Pentium M laptop with the mm2 kernel, 
> > CONFIG_PREEMPT_NONE=y, other preemption configs are not set.
> > 
> > -- charles
> 
> You might take a look at the fall back timer interrupt 
> mechanism in OProfile to see how it works. In particular look 
> at the linux/driver/oprofile/timer_int.c.
> 
> I noticed there are a couple things that were i386 specific 
> in the example, use of regs->eip and task_pt_regs.
> 
> 
> -Will
>