Re: comments on Performance Counters for Linux (PCL)
From: Andi Kleen
Date: Fri May 29 2009 - 02:44:31 EST
> > Take Itanium, it has 4 priv levels and the PMU counters can monitor at
> > any priv levels or combination thereof?
> x86 has more priv rings too, but linux only uses 2, kernel (ring 0) and
> user (ring 2 iirc). Does ia64 expose more than 2 priv levels in linux?
In a hardware virtualized environment x86 Linux uses at least four.
And yes ia64 also exposes more I believe, e.g. it has the fancy
"system calls that run in user context"
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/