Date: Tue, 12 Jun 2012 11:11:36 +0200 (CEST) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-stable@FreeBSD.ORG, momchil@xaxo.eu Subject: Re: ULE Scheduler Message-ID: <201206120911.q5C9BaGj097969@lurza.secnetix.de> In-Reply-To: <86sje17jnx.wl%momchil@xaxo.eu>
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?????? ?????? <momchil@xaxo.eu> wrote: > I compiled the same kernel with the 4BSD scheduler today and it seems > that the processes jump accross cores too. What exactly is the problem that you're seeing? Do you have performance problems? If so, then they're probably *not* caused by processes "jumping across cores". Have you read Daniel Kalchev's reply in this thread? He explained very well why that's not a problem usually. Also note that top(1) only shows one snapshot every second or two. It does not show you the hundreds (or thousands) of thread switches that happen every second. In fact, top(1) shows a very misleading picture because it creates the wrong impression that your CPU-bound processes are almost the only ones being scheduled on your cores. Most of the time, people looking at top(1) see problems that don't exist. Another example is the amount of "free" memory displayed by top that is often misinterpreted. I suggest you just keep the standard scheduler (i.e. ULE). If you don't have a performance problem (i.e. a problem that you can measure by other means than top), then don't try to fix it. Chances are you make things worse. 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 "The scanf() function is a large and complex beast that often does something almost but not quite entirely unlike what you desired." -- Chris Torek
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