Re: Locking comment on shrink_caches()

Ingo Molnar
2001-09-26T17:45:01Z

On Tue, 25 Sep 2001, David S. Miller wrote:

> I'm very curious as to what workloads are showing pagecache_lock as
> a bottleneck. We haven't noticed this particular bottleneck in most
> of the workloads we are running. Is there a good workload that shows
> this type of load?
>
> Again, I defer to Ingo for specifics, but essentially something
> like specweb99 where the whole dataset fits in memory.

it was SPECweb99 tests done in 32 GB RAM, 8 CPUs, where the pagecache was
nearly 30 GB big. We saw visible pagecache_lock contention on such
systems. Due to TUX's use of zerocopy, page lookups happen at a much
larger frequency and they are not intermixed with memory copies - in
contrast with workloads like dbench.

Ingo