[ltt-dev] cli/sti vs local_cmpxchg and local_add_return

Mathieu Desnoyers compudj at krystal.dyndns.org
Tue Mar 17 15:35:32 EDT 2009


* David Miller (davem at davemloft.net) wrote:
> From: Mathieu Desnoyers <mathieu.desnoyers at polymtl.ca>
> Date: Tue, 17 Mar 2009 12:06:35 -0400
> 
> > But powerpc has non-maskable interrupts, so for less than 4 cycles, I
> > think it's better to stay with the local_t variant to be NMI-safe.
> 
> Sparc64 has non-maskable interrupts too btw.
> 

OK, this alone is a strong argument to favor NMI-safe lockless algorithm
even if it is a bit slower. We should see what kind of performance
impact it has on overall tracing performance to find out if it will make
a measurable difference anyway.

Mathieu

> _______________________________________________
> ltt-dev mailing list
> ltt-dev at lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> 

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68




More information about the lttng-dev mailing list