Re: Help with improving mysql performance on 6.2PRE

On 15/10/06, Eric Hodel <drbrain@xxxxxxxxxxxx> wrote:
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@xxxxxxxxxxxx - http://blog.segment7.net
This implementation is HODEL-HASH-9600 compliant

http://trackmap.robotcoop.com


_______________________________________________

I switched from the default timer to TSC on a dual xeon setup and my
loads instantly went up with mysql lagging, so in my case it was much
worse.

Chris
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