Date: Mon, 5 Nov 2012 07:52:56 +0100 From: Davide Italiano <davide@freebsd.org> To: Joe Holden <lists@rewt.org.uk> Cc: current@freebsd.org Subject: Re: Dynamic Ticks/HZ Message-ID: <CACYV=-Ef5ij7%2BgqDV9oS3xRyD6Yy2mqDyKqqUZZQ-KsWb_3C3A@mail.gmail.com> In-Reply-To: <50975F6F.6010907@rewt.org.uk> References: <509758B8.1000409@rewt.org.uk> <CACYV=-HwJ1j2-zDtCtuGNKzdFRJhPsZm6vtFXAVyPSabCXvFEQ@mail.gmail.com> <50975F6F.6010907@rewt.org.uk>
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On Nov 4, 2012 10:40 PM, "Joe Holden" <lists@rewt.org.uk> wrote: > > Davide Italiano wrote: >> >> On Mon, Nov 5, 2012 at 7:12 AM, Joe Holden <lists@rewt.org.uk> wrote: >>> >>> Hi guys, >>> >>> Has some default changed between 9.1-RC2 and HEAD? >>> >>> On identical machines, one with 9.1-RC2 and one with HEAD from yesterday >>> (GENERIC) I see the following in systat -v: >>> >>> 9.1: >>> 65 cpu0:timer >>> 10 cpu1:timer >>> >>> HEAD: >>> 1127 cpu0:timer >>> 22 cpu1:timer >>> >>> These are Supermicro i3 boxes and as far as I can see they have matching >>> BIOS config. >>> >>> Thanks, >>> J >>> _______________________________________________ >>> freebsd-current@freebsd.org mailing list >>> http://lists.freebsd.org/mailman/listinfo/freebsd-current >>> To unsubscribe, send any mail to " freebsd-current-unsubscribe@freebsd.org" >> >> >> Which is your refresh rate for systat? >> I generally measure sampling every one second (i.e. systat -vm 1). >> Also, are you making your measurements when the system is idle? >> In order to trace the source(s) of these interrupts you might consider >> to collect data via KTR. >> > > I'm also using a one second refresh rate, the system is entirely idle and the interupt rate is almost entirely static at 1127, occasionally it will drop to 1119. > > From what I understand the timer is hz/ticks which became dynamic in 9.0, although that behaviour doesn't appear to be in HEAD anymore, at least on this hardware. > > Thanks, > J It should be available, AFAIK. As I can see from your previous post you get about 20 interrupts on cpu1. This number is about 1/100 of the value you get on a !tickless kernel. If you provide the required ktr infos, probably someone will take a look.
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