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From: Ivan Voras <ivoras@freebsd.org>
Date: Sat, 20 Oct 2012 21:28:25 +0200
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Subject: Re: NFS server bottlenecks
To: Rick Macklem <rmacklem@uoguelph.ca>
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Cc: "freebsd-hackers@freebsd.org Hackers" <freebsd-hackers@freebsd.org>,
 Nikolay Denev <ndenev@gmail.com>
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On 20 October 2012 14:45, Rick Macklem <rmacklem@uoguelph.ca> wrote:
> Ivan Voras wrote:

>> I don't know how to interpret the rise in context switches; as this is
>> kernel code, I'd expect no context switches. I hope someone else can
>> explain.
>>
> Don't the mtx_lock() calls spin for a little while and then context
> switch if another thread still has it locked?

Yes, but are in-kernel context switches also counted? I was assuming
they are light-weight enough not to count.

> Hmm, I didn't look, but were there any tests using UDP mounts?
> (I would have thought that your patch would mainly affect UDP mounts,
>  since that is when my version still has the single LRU queue/mutex.

Another assumption - I thought UDP was the default.

>  As I think you know, my concern with your patch would be correctness
>  for UDP, not performance.)

Yes.