Help with improving mysql performance on 6.2PRE

Chuck Swiger cswiger at
Fri Oct 13 11:49:09 PDT 2006

On Oct 13, 2006, at 11:26 AM, Eric Hodel wrote:
>>> Or did that change recently?
>> It's only on certain systems, apparently.
> Is there a list of systems where it is safe to use the TSC with  
> SMP?  Or some script we can run?

The problem of the TSC clocks getting out of sync affects pretty much  
all AMD X2 dual-core CPUs, as well as the older 32-bit Althon MP  
CPUs; the Intel Xeon and Core Duo CPUs seem to do a lot better,  
although older Intel CPUs have also been reported to show problems  
with the TSC.

Disabling the fancy power-management capabilities (SpeedStep,  
PowerNow, Cool-n-quiet) to prevent the system from adjusting the CPU  
clock frequencies seems to reduce the extent of the problem.   
However, if you want your system clock to work reliably, using the  
ACPI-safe or i8254 timecounters is going to do much better than using  
the faster-but-unreliable TSC method.


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