Date: Sat, 18 Sep 2010 14:27:43 +0300 From: Andriy Gapon <avg@freebsd.org> To: Robert Watson <rwatson@freebsd.org> Cc: freebsd-hackers@freebsd.org Subject: Re: zfs + uma Message-ID: <4C94A22F.1070608@freebsd.org> In-Reply-To: <alpine.BSF.2.00.1009181221560.86826@fledge.watson.org> References: <4C93236B.4050906@freebsd.org> <4C935F56.4030903@freebsd.org> <alpine.BSF.2.00.1009181221560.86826@fledge.watson.org>
next in thread | previous in thread | raw e-mail | index | archive | help
on 18/09/2010 14:23 Robert Watson said the following: > I've been keeping a vague eye out for this over the last few years, and haven't > spotted many problems in production machines I've inspected. You can use the > umastat tool in the tools tree to look at the distribution of memory over > buckets (etc) in UMA manually. It would be nice if it had some automated > statistics on fragmentation however. Short-lived fragmentation is likely, and > isn't an issue, so what you want is a tool that monitors over time and reports > on longer-lived fragmentation. > > The main fragmentation issue we've had in the past has been due to mbuf+cluster > caching, which prevented mbufs from being freed usefully in some cases. Jeff's > ongoing work on variable-sized mbufs would entirely eliminate that problem... Robert, just in case, this thread is not about fragmentation, it's about per-cpu buckets, number of items in them and size of the items. -- Andriy Gapon
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4C94A22F.1070608>