Date: Thu, 4 Oct 2007 14:32:39 +0200 (CEST) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-stable@FreeBSD.ORG, matrix@itlegion.ru Subject: Re: Quation about HZ kernel option Message-ID: <200710041232.l94CWd6W056143@lurza.secnetix.de> In-Reply-To: <02d401c805cb$abf59ec0$0c00a8c0@Artem>
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Artem Kuchin <> wrote: > What value of HZ option would you recommend > for a hosting (web) server with a lot of processes > (about 900) and polling off (as decided from previous > discussion polling is useless in > this situation). In that case, I would recommend not to override the default at all (which is 1000). > What parts of kernel does this option affect? What > depends on it? The value of HZ specifies the minimum timing quantum of the kernel. It affects the granularity of the scheduler and all timing-related functions (nanosleep(2) and others), and the accuracy of dummynet and polling. I'm sure there are more things. Basically, the kernel cannot handle time slices smaller than 1/HZ seconds, for any purpose. Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M. Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung: secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün- chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd One Unix to rule them all, One Resolver to find them, One IP to bring them all and in the zone to bind them.home | help
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