Date: Tue, 13 Oct 2009 14:12:54 +0200 From: Ivan Voras <ivoras@freebsd.org> To: freebsd-stable@freebsd.org Subject: Re: Extreme console latency during disk IO (8.0-RC1, previous releases also affected according to others) Message-ID: <hb1qs0$qjd$1@ger.gmane.org> In-Reply-To: <CC16B639-7A75-4016-A8A8-5C59E9CD5E95@exscape.org> References: <E316139E-FFCF-432F-8DCE-62B120C38E55@exscape.org> <CC16B639-7A75-4016-A8A8-5C59E9CD5E95@exscape.org>
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Thomas Backman wrote: > I'm copying this over from the freebsd-performance list, as I'm looking > for a few more opinions - not on the problems *I* am having, but rather > to check whether the problem is universal or not, and if not, find a > possible common factor. > In other words: I want to hear about your experiences, *good or bad*! > > Here's the original thread (not from the beginning, though): > http://lists.freebsd.org/pipermail/freebsd-performance/2009-October/003843.html > > > Long story short, my version: when the disk is stressed hard enough, > console IO becomes COMPLETELY unbearable. 10+ seconds to switch between > windows in screen(1), running (or even typing) simple commands, etc. > This happens both via SSH and the serial console. Hmm, this looks familiar - I've noticed it before on the physical (VGA) console and I notice it all the time under VMWare. It sort of looks like disk IO really blocks network IO in this case - I use the VMs over ssh.
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