Date: Fri, 30 Jan 2009 16:31:29 +0100 From: Julian Stecklina <js@alien8.de> To: freebsd-xen@freebsd.org Subject: Re: kern.hz = 10 Message-ID: <8763jwkdym.fsf@tabernacle.localnet> References: <87ocxp1tym.fsf@tabernacle.localnet> <1233285247.24925.4.camel@phoenix.blechhirn.net> <871vul1nqk.fsf@tabernacle.localnet> <9bbcef730901300214s19c91071vf9241cd7cd40ba57@mail.gmail.com>
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Ivan Voras <ivoras@freebsd.org> writes: > 2009/1/30 Julian Stecklina <js@alien8.de>: >> Mister Olli <mister.olli@googlemail.com> writes: >> >>> Hi, >>> >>> I've never experimented with the kern.hz variable, but on all >>> configuration examples for 8-CURRENT if always seen 'kern.hz=100'. >>> >>>>From where did you get your configuration? >> >> I use the default config (albeit renamed to BLITZXEN) from 8-CURRENT. > > Due to bad performance of high HZ in VMs, in 8-CURRENT it is > explicitly reduced to 10 if the kernel is running under any kind of > virtual environment. This is a somewhat theoretical number and > probably needs tuning. Probably. > If you're interested in trying it out, you can increase it by adding > "kern.hz=xxx" to /boot/loader.conf and seeing what is the actual > performance influence of high HZ under Xen. I am going to do that once the timing stuff is figured out. No point in making benchmarks when the clock is confused. :) I cannot repeat it enough: Still great to see FreeBSD on Xen! Regards, -- Julian Stecklina Well, take it from an old hand: the only reason it would be easier to program in C is that you can't easily express complex problems in C, so you don't. - Erik Naggum (in comp.lang.lisp)
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