Re: [PATCH] Preemption Latency Measurement Tool

Robert Love
2001-09-20T02:56:20Z

On Wed, 2001-09-19 at 21:13, David Lang wrote:
> also how useful is the latency info once swapping starts? if you have
> something that gets swapped out it will have horrible latency and skew the
> results (or at the very least you won't know if the problem is disk IO or
> fixable problems)

Its not that bad because the patch measures latency across points where
preemption was enabled and disabled -- the various kernel locking
mechanisms.

Thus either page fault holds a lock and it is a legimate latency
recorded over that specific lock, or it doesn't in which case its not an
issue.

--
Robert M. Love
rml at ufl.edu
rml at tech9.net