Messages in this thread | | | Subject | Re: [RFC PATCH] introduce sys_membarrier(): process-wide memory barrier | From | Steven Rostedt <> | Date | Thu, 07 Jan 2010 09:27:38 -0500 |
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On Thu, 2010-01-07 at 01:19 -0500, Mathieu Desnoyers wrote:
> I see your point.
Actually you are missing the point ;-)
> > This would probably be good for machines with very large number of cpus > and without IPI broadcast support, running processes with only few > threads. I really start to think that we should have some way to compare > the number of threads belonging to a process and choose between the > broadcast IPI and the per-cpu IPI depending if we are over or under an > arbitrary threshold.
This has nothing to do with performance. It has to do with a thread should not interfere with a thread belonging to another process. We really don't care how long the sys_membarrier() takes (it's the slow path anyway). We do care that a critical RT task is being interrupted by some java thread sending thousands of IPIs.
-- Steve
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