Re: FreeBSD-11.0-CURRENT on ARM: performance and load average

From: Maxim V FIlimonov <che_at_bein.link>
Date: Sun, 21 Sep 2014 01:04:27 +0400
On Saturday 20 September 2014 13:24:08 Ian Lepore wrote:
> Since it's happening only on that hardware, there's a good chance the
> problem is in the allwinner a10/a20 clock driver, not in the general
> eventtimer code.  In fact, looking at the code it appears that a
> divide-by-16 is being set in the hardware, but not accounted for when
> setting the frequency of the eventtimer.
> 
> Hmm, it should affect the timecounter too, in which case you'd see
> time-of-day advancing 16x too fast.  If ntpd is running it would need to
> step the clock pretty frequently, which would show up in syslog.
> 

I'm running FreeBSD-current on the board right now, the time is just fine.

> I don't have hardware to test on, please see if the attached patch makes
> a difference.
> 
 
Well, it did: with the patch applied, the time ran about 60 times as fast as 
it should have. I didn't notice any changes with load average, though: maybe 
it's because I forgot to turn that sysctl setting I set before back to 0.

wbr, Maxim Filimonov
che_at_bein.link
Received on Sat Sep 20 2014 - 19:04:32 UTC

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