Date: Sun, 15 Aug 2004 09:57:57 +0200 From: Andrea Campi <andrea+freebsd_current@webcom.it> To: Peter Jeremy <PeterJeremy@optushome.com.au> Cc: current@freebsd.org Subject: Re: Summary of discussion of harvester/random locking and performance optimization Message-ID: <20040815075757.GA657@webcom.it> Resent-Message-ID: <20040821180516.GD690@webcom.it> In-Reply-To: <20040815074616.GJ423@cirb503493.alcatel.com.au> References: <Pine.NEB.3.96L.1040814105622.99198C-100000@fledge.watson.org> <20040815074616.GJ423@cirb503493.alcatel.com.au>
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On Sun, Aug 15, 2004 at 05:46:16PM +1000, Peter Jeremy wrote:
> >systems may not have a TSC, and insead read the system clock (ouch!). We
> >may want to investigate what approaches we can use to mitigate this,
> >especially if systems like soekris boxes don't have TSC.
>
> in efficiently supporting the i486. If the various low-end iA32 clones
> do support the TSC, there seems little point in changing the status quo.
Since nobody chimed in yet, my Soekris box has:
kern.timecounter.stepwarnings: 0
kern.timecounter.nbinuptime: 76822456
kern.timecounter.nnanouptime: 2
kern.timecounter.nmicrouptime: 2728
kern.timecounter.nbintime: 2659850
kern.timecounter.nnanotime: 596
kern.timecounter.nmicrotime: 2659254
kern.timecounter.ngetbinuptime: 15352306
kern.timecounter.ngetnanouptime: 3901
kern.timecounter.ngetmicrouptime: 278552
kern.timecounter.ngetbintime: 0
kern.timecounter.ngetnanotime: 0
kern.timecounter.ngetmicrotime: 15
kern.timecounter.nsetclock: 5
kern.timecounter.hardware: i8254
kern.timecounter.choice: ELAN(-2000) i8254(0) dummy(-1000000)
kern.timecounter.tick: 1
This is the ELAN-based model, which is a 486 class CPU. More powerful
models might or might not have the TSC. I haven't investigated the
cost/benefit of using ELAN timecounter instead of i8254.
Bye,
andrea
--
I believe the technical term is "Oops!"
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