2 x quad-core system is slower that 2 x dual core on FreeBSD

Alexey Popov lol at chistydom.ru
Tue Nov 20 03:27:20 PST 2007


Kris Kennaway wrote:
>>>>>> CPU states:  9.5% user,  0.0% nice, 82.0% system,  0.5% 
>>>>>> interrupt,  8.0% idle
>>>>> A wild idea that might not help: try reducing kern.hz in 
>>>>> loader.conf to
>>>>> something like 100 and see if something significant changes.
>> Usually on PHP backends slow PHP code eats most of the CPU time. I 
>> have %user much bigger than %system in CPU states.
>> But now %system is much bigger than %user and I can conclude that on 
>> 8-core server FreeBSD consumes more CPU time than PHP.
> That is one possibility, but you still need to look at the actual 
> throughput on these machines before making conclusions about which is 
> performing better.  Can you please provide those numbers for 6.x, 7.x 
> with ULE and 4BSD on the 4-core and 8-core systems?
Ok, here's results of practical research. The following is approximate 
maximum qps that backends can survive with my workload:

7-STABLE quad ULE	20
7-STABLE quad 4BSD	17
6-STABLE quad		14
6-STABLE dual		21
Linux CentOS 5 quad	>50

With best regards,
Alexey Popov

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