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Date: Wed, 25 Feb 2015 18:36:26 -0500
From: Garrett Wollman <wollman@csail.mit.edu>
To: Alfred Perlstein <alfred@freebsd.org>
Subject: Re: Implementing backpressure in the NFS server
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<<On Wed, 25 Feb 2015 18:29:45 -0500, Alfred Perlstein <alfred@freebsd.org> said:

> I think your other suggestions are fine, however the problem is that:
> 1) they seem complex for an edge case
> 2) turning them on may tank performance for no good reason if the 
> heuristic is met but we're not in the bad situation

I'm OK with trading off performance for one user against availability
for the other 800.

I'm pleased to hear that FreeNAS was fine with 256 threads as the
default; I'm going to try running with that to see if we encounter any
other scaling issues as a result.  (Our servers are all 12-core,
24-thread systems with buckets of memory, and I remember increasing
the thread count as high as 128 previously, but I also remember having
to back it down to 64 for some reason.)

-GAWollman