Date: Fri, 30 Jan 2009 13:52:47 +0100 From: Mister Olli <mister.olli@googlemail.com> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-xen@freebsd.org, Julian Stecklina <js@alien8.de> Subject: Re: kern.hz = 10 Message-ID: <1233319967.24925.19.camel@phoenix.blechhirn.net> In-Reply-To: <9bbcef730901300214s19c91071vf9241cd7cd40ba57@mail.gmail.com> References: <87ocxp1tym.fsf@tabernacle.localnet> <1233285247.24925.4.camel@phoenix.blechhirn.net> <871vul1nqk.fsf@tabernacle.localnet> <9bbcef730901300214s19c91071vf9241cd7cd40ba57@mail.gmail.com>
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Hi, > 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. Oh I didn't knew that. *SORRY* > 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've run on 100HZ quite some time now and did have the impression that 8-CURRENT is slow. It's even faster on copy processes as 7 under VMware on a host machine which is 3 years younger... .. Mr. Olli
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