Date: Thu, 31 Jan 2002 17:36:10 -0500 (EST) From: "Storms of Perfection" <gary@outloud.org> To: <thierry@herbelot.com> Cc: <replicator@ngs.ru>, <hackers@FreeBSD.ORG> Subject: Re: Clock Granularity (kernel option HZ) Message-ID: <3197.208.141.46.249.1012516570.squirrel@test.outloud.org> In-Reply-To: <3C59C198.78EDFEA9@herbelot.com> References: <3C59C198.78EDFEA9@herbelot.com>
next in thread | previous in thread | raw e-mail | index | archive | help
I'm going to benchmark different network senarious with different options to see what I can get, and what works best. If someone wants to help me out, I could maybe write up a article about it? > I've used a large collection of PCs running somewhat real-time network > analysis with a HZ set at 5000Hz with absolutely no ill effects (this > was with P-III-450's) > > using HZ=10000 was outside of the possibilities of the machines. > > one big gain is with timing, which will be better (I myself used NTP to > have a coherent timing on the collection of PC's, with an > inter-correlation better than 1 ms) > > TfH > > Eugene Panchenko wrote: >> >> Hello! >> >> 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 Gary Stanley Network Security Engineer PRECISIONet/Webjockey, Inc. (877) 595-8570 Tickle us, do we not laugh? Prick us, do we not bleed? Wrong us, shall we not revenge?" (Merchant of Venice II i 56-63, paraphrase) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3197.208.141.46.249.1012516570.squirrel>