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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Maxim Sobolev <sobomax@FreeBSD.org>
References: <200810270625.m9R6P2a8029701@svn.freebsd.org>
Date: Thu, 30 Oct 2008 13:20:34 +0100
In-Reply-To: <200810270625.m9R6P2a8029701@svn.freebsd.org> (Maxim Sobolev's
	message of "Mon, 27 Oct 2008 06:25:02 +0000 (UTC)")
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Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org,
	src-committers@freebsd.org
Subject: Re: svn commit: r184323 - head/sys/kern
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Maxim Sobolev <sobomax@FreeBSD.org> writes:
> Log:
>   Default HZ value (1,000) on i386/amd64 is not very virtual machine frie=
ndly.
>   Due to the nature of the beast it causes lot of unproductive overhead. =
This
>   is especially bad when running SMP kernel on VMWare with several virtual
>   processors - idle FreeBSD guest with SMP kernel takes 150% host CPU tim=
e on my
>   dual-core MacBook Pro when I am enabling two virtual CPUs, making even =
host
>   not very usable. Detect when we are running in the sandbox and reduce HZ
>   to 10 (can be adjusted via VM_HZ in the kernel config) in such cases. T=
his
>   brings host CPU usage of idle FreeBSD/SMP on two virtual processors down
>   to 10%.

What, too chicken to go whole hog and make the kernel tickless?  :)

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no