[CentOS] Re: Tyan Thunder K8SE S2892 Report / here: Tyan S4882

[Kay Diederichs]

Kirk Bocek wrote:
...
> However, the boot messages showed:
> 
> 	warning: many lost ticks.
> 	Your time source seems to be instable or some driver is hogging 	
> interrupts
> 
> and several repeating messages:
> 
> 	powernow-k8: error - out of sync...
> 
> Also, /proc/cpuinfo showed each cpu as running at about 1004Mhz with
> about 900 bogomips. Not what I expected.
> 
> I decided to press ahead and added a couple of drives the the 3Ware,
> created a unit, formatted it and began benchmarking the array. The
> "powernow" messages continued to occur and then the 3Ware driver started
> issuing error messages. Eventually the system crashed and stopped
> responding.
> 
> Googling on the powernow error message let me know that the kernel
> wizards had started to fix some powernow bugs starting with about kernel
> 2.6.10. Of course the stock CentOS 4.1 kernel is 2.6.9-11.
> 
> So I downloaded, compiled and installed kernel 2.6.12.3. On rebooting,
> the error messages went away and the 3Ware worked without complaint. Now
> /proc/cpuinfo showed each cpu running at 2009.267 Mhz with 4014.08
> bogomips. Ah, much better! In addition, the system came up in with NUMA
> enabled. Looks like the Red Hat kernel had it turned off by default.
...
> Comments and corrections are encouraged.
> 
> Kirk Bocek

This is what I get with the standard (2.6.9-11ELsmp) kernel on a quad-opteron 
(2.6GHz) Tyan S4882 - actually the Tyan TX46 ( 
http://www.tyan.com/products/html/tx46b4882.html ):

powernow-k8: Found 4 AMD Athlon 64 / Opteron processors (version 1.00.09b)
powernow-k8:    0 : fid 0x12 (2600 MHz), vid 0x6 (1400 mV)
powernow-k8:    1 : fid 0x10 (2400 MHz), vid 0x8 (1350 mV)
powernow-k8:    2 : fid 0xe (2200 MHz), vid 0xa (1300 mV)
powernow-k8:    3 : fid 0xc (2000 MHz), vid 0xc (1250 mV)
powernow-k8:    4 : fid 0xa (1800 MHz), vid 0xe (1200 mV)
powernow-k8:    5 : fid 0x2 (1000 MHz), vid 0x12 (1100 mV)
powernow-k8: cpu_init done, current fid 0x12, vid 0x6
powernow-k8:    0 : fid 0x12 (2600 MHz), vid 0x6 (1400 mV)
powernow-k8:    1 : fid 0x10 (2400 MHz), vid 0x8 (1350 mV)
powernow-k8:    2 : fid 0xe (2200 MHz), vid 0xa (1300 mV)
powernow-k8:    3 : fid 0xc (2000 MHz), vid 0xc (1250 mV)
powernow-k8:    4 : fid 0xa (1800 MHz), vid 0xe (1200 mV)
powernow-k8:    5 : fid 0x2 (1000 MHz), vid 0x12 (1100 mV)
powernow-k8: cpu_init done, current fid 0x12, vid 0x6
powernow-k8:    0 : fid 0x12 (2600 MHz), vid 0x6 (1400 mV)
powernow-k8:    1 : fid 0x10 (2400 MHz), vid 0x8 (1350 mV)
powernow-k8:    2 : fid 0xe (2200 MHz), vid 0xa (1300 mV)
powernow-k8:    3 : fid 0xc (2000 MHz), vid 0xc (1250 mV)
powernow-k8:    4 : fid 0xa (1800 MHz), vid 0xe (1200 mV)
powernow-k8:    5 : fid 0x2 (1000 MHz), vid 0x12 (1100 mV)
powernow-k8: cpu_init done, current fid 0x12, vid 0x6
powernow-k8:    0 : fid 0x12 (2600 MHz), vid 0x6 (1400 mV)
powernow-k8:    1 : fid 0x10 (2400 MHz), vid 0x8 (1350 mV)
powernow-k8:    2 : fid 0xe (2200 MHz), vid 0xa (1300 mV)
powernow-k8:    3 : fid 0xc (2000 MHz), vid 0xc (1250 mV)
powernow-k8:    4 : fid 0xa (1800 MHz), vid 0xe (1200 mV)
powernow-k8:    5 : fid 0x2 (1000 MHz), vid 0x12 (1100 mV)
powernow-k8: cpu_init done, current fid 0x12, vid 0x6
ACPI: (supports S0 S1 S4 S5)

which clearly shows that the kernel detects the powernow features nicely.
Actually powernow adjusts the CPU speed dynamically according to the 
requirements - an idle server runs all CPUs at 1000MHz; whereas at higher loads 
the speed goes up to 2600MHz automagically (I grepped MHz in /proc/cpuinfo).

All of this is no different when using the 2.6.12 kernel. I have not found a 
single problem with the system.

One question of my own: I am pretty much confused by the multitude of BIOS 
options which influence the handling of the memory: memory hole remapping, SRAT 
table and such. Is there anybody who can say definitely what works best on the 
standard RH kernel? I tried a number of possibilities but did not find any 
differences in lmbench benchmarks. The existence of "NUMA" is only reported by 
the 2.6.12 kernel, not by the RH one. Currently running with memory remapping 
"SOFTWARE", SRAT table "DISABLED" and everything else at "AUTO".

Kay