Help with improving mysql performance on 6.2PRE

Eric Hodel drbrain at
Sat Oct 14 23:10:53 PDT 2006

On Oct 13, 2006, at 1:13 PM, Kris Kennaway wrote:
> On Fri, Oct 13, 2006 at 11:49:04AM -0700, Chuck Swiger wrote:
>> 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.
> Beyond that, just see if it works ;-)

How "safe" is it to switch timecounters?  I don't have a spare  
machine to test on...

 From my readings on switching the TSC over the past several months I  
think that if it doesn't work I'll see is ntpd adjusting my system  
clock more often (or falling out of sync).  I don't know if this will  
corrupt mysql while its running though (which is my fear).

FWIW I have a "Dual Core AMD Opteron(tm) Processor 270".

Eric Hodel - drbrain at -
This implementation is HODEL-HASH-9600 compliant

More information about the freebsd-performance mailing list