Date: Fri, 1 Feb 2002 23:35:56 +0200 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: Storms of Perfection <gary@outloud.org> Cc: replicator@ngs.ru, hackers@freebsd.org Subject: Re: Clock Granularity (kernel option HZ) Message-ID: <20020201213556.GC5412@hades.hell.gr> In-Reply-To: <2651.208.141.46.249.1012504967.squirrel@test.outloud.org> References: <web-8711515@intranet.ru> <2651.208.141.46.249.1012504967.squirrel@test.outloud.org>
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I've been running for quite some time a 5.0-CURRENT box with HZ=1000 set to it's kernel configuration. Apart from a faster blinking rate of the syscons cursor, I haven't seen much difference. This is my own personal workstation though, and it's almost never loaded too much :-/ - Giorgos On 2002-01-31 14:22, Storms of Perfection wrote: > I am intrested in this as well. > > > I've seen various postings on the Net where people reported > > network-related and overall performance improvements caused > > by settig HZ kernel option to 1000 (for example), that is, > > reducing a tick size to 1ms for their FreeBSD and Linux > > systems. However, several problems seem to arise, such as > > some device drivers do not include HZ in calculating their > > timeout value, but simply assume HZ to be 100, and also some > > utility programs such as top or ps take timing information > > from the kernel in ticks, also assuming 10ms ticks, however, > > most of these saying were related to Linux. How safe it is > > to bump up HZ to, say, 1000 in FreeBSD (I use 4.5-STABLE)? > > What pitfals will I encounter (drivers, top/ps)? Is there > > are going to be [promised] performance increase? Do I > > really need it? Thank you. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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