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Date: Tue, 21 Sep 2010 09:20:00 +0300
From: Andriy Gapon <avg@freebsd.org>
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To: Jeff Roberson <jroberson@jroberson.net>
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Cc: Andre Oppermann <andre@freebsd.org>, Jeff Roberson <jeff@freebsd.org>,
	Robert Watson <rwatson@freebsd.org>, freebsd-hackers@freebsd.org
Subject: Re: zfs + uma
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on 19/09/2010 11:42 Andriy Gapon said the following:
> on 19/09/2010 11:27 Jeff Roberson said the following:
>> I don't like this because even with very large buffers you can still have high
>> enough turnover to require per-cpu caching.  Kip specifically added UMA support
>> to address this issue in zfs.  If you have allocations which don't require
>> per-cpu caching and are very large why even use UMA?
> 
> Good point.
> Right now I am running with 4 items/bucket limit for items larger than 32KB.

But I also have two counter-points actually :)
1. Uniformity.  E.g. you can handle all ZFS I/O buffers via the same mechanism
regardless of buffer size.
2. (Open)Solaris does that for a while and it seems to suit them well.  Not
saying that they are perfect, or the best, or an example to follow, but still
that means quite a bit (for me).

-- 
Andriy Gapon