Re: [PATCH 0/26] oprofile: Performance counter multiplexing

From: Andi Kleen
Date: Sun Mar 07 2010 - 22:51:52 EST

> the tests I run with oprofile do not indicate unreliable ring_buffer

Did you try it with callgraph mode? That seems to be worst.

> behavior. Maybe my use cases and loads are different. Can you describe
> a setup where this may happen for sure? What is the impact, do you

Seeing it on very busy 16 CPU and larger systems.

> have lost samples or inconsistent buffer data? Is the data loss in

There are a lot of lost samples, callgraphs are incomplete etc.

> kernel or user space? Also, I am not aware that the ring_buffer is

Not sure.

ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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