Re: severely bad timekeeping

[Andre Skarzynski <andresk%mac.com@localhost>]

Hi,

I have a 7600/132 with G3 accelerator card, but I can't help w.r.t  
ntp problems. I am synching time using ntp and it appears to be  
working fine. About the CPU upgrade card, I have been using the  
following kernel settings with a Sonnet G3 400 Mhz 1Mb cache card and  
also with a Newertech G3 333 1Mb with success. I hope this helps.  
Some others have given some useful info on where to look for settings.

options         L2CR_CONFIG="(L2SIZ_1M|L2CLK_20|L2RAM_PIPELINE_BURST)"

dmesg output:
...
cpu0 at mainbus0: 750 (Revision 3.0), ID 0 (primary)
cpu0: HID0 8090c2a4<EMCP,DOZE,DPM,ICE,DCE,SPD,SGE,BTIC,BHT>,  
powersave: 1
cpu0: 400.00 MHz, no-parity 1MB WB L2 cache (PB SRAM) at 2:1 ratio
...

Kind Regards,

André

On 17 Apr 2009, at 05:53, der Mouse wrote:

> I've got a macppc machine running 4.0.1.  ntp doesn't work right, and
> I'm wondering whether this is a problem with my particular machine or
> with this kind of machine (FWVO "kind"), and whether there's  
> anything I
> can do to fix it.
>
> The machine started life as a 7600/132 - for example, that's what's
> printed on the case - but (I'm told) it's got a G3 upgrade in it.
> dmesg.boot describes the CPU thus (I am not comptent to say whether
> this means it really is a G3 or not, which is why I put it that way):
>
> cpu0 at mainbus0: 750 (Revision 2.2), ID 0 (primary)
> cpu0: HID0 8090c0a4<EMCP,DOZE,DPM,ICE,DCE,SGE,BTIC,BHT>, powersave: 1
> cpu0: 305.89 MHz L2 cache present but not enabled
>
> The time it keeps is wrong by almost a percent - it runs approximately
> half a second per minute slow.  ntp fails to sync under these
> circumstances (yes, I did check for an old ntp.drift file; this is
> being tested after destroying ntp.drift).  Killing ntpd and running
> ntpdate -b once a minute produces matching results (a correction of
> about .48 seconds each time around).
>
> Any ideas?  I can provide more details, if you can tell me where to
> find them....
>
> In passing, what would I need to do to figure out what L2CR_CONFIG
> settings I want for this CPU?  "L2 cache present but not enabled"
> sounds like a performance killer, and the macppc FAQ points to list
> mail indicating that setting L2CR_CONFIG is the right magic, but
> doesn't give much guidance on what to set it to.
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