RHEL 6 CPU load

[Blake Hudson]

- wrote the following on 11/20/2013 12:30 PM:
>> Depending on your OS and Bind settings, Bind may be performing IPv6/AAAA
>> queries in parallel to IPv4/A queries. If IPv6 is disabled on your RHEL5
>> server I suspect they may only be performing IPv4/A queries during
>> recursion. You might check if this is, at least in part, responsible for the
>> additional load.
>>
> I just compiled a version of bind on the RHEL 6 system with ipv6
> disabled and the results were the same.
>
>> You didn't provide the same CPU information about your RHEL 5 builds as you
>> did for your RHEL6 system, so I just responded about the information you did
>> provide. Are these 24/32 core systems? Do the same number of named child
>> processes run on both the RHEL5 and RHEL6 systems? I'm going to assume that
>> you've already examined query load on the servers and found them similar.
> The other system only has 16 CPUs but named runs at a third of the CPU
> that the RHEL 6 box does.
>
> RHEL 5:
> version: 9.9.4-P1 () <id:07aaf1ef>
> CPUs found: 16
> worker threads: 16
> UDP listeners per interface: 16
> number of zones: 169
> debug level: 0
> xfers running: 0
> xfers deferred: 0
> soa queries in progress: 0
> query logging is ON
> recursive clients: 30/9900/10000
> tcp clients: 0/100
> server is up and running
>

What about the information from top? When comparing RHEL5 and RHEL6 
systems, I would compare the total CPU usage of the server (out of 100% 
not 2400% or 1600%).

Since the hardware is different, comparing a 16 named threads on a 16 
core box at ???MHz against a 24 core box with 24 named threads at ???MHz 
may not necessarily be valid. If the CPUs are running at the same 
frequency (look at what speed they are actually running at vs the max 
speed... see /proc/cpuinfo ) then you can probably account for the 16 vs 
24 core difference pretty easily. If the CPUs run at more than 
negligibly different frequencies you will have to factor that into any 
comparison or make the frequencies the same to make a 1:1 good comparison.

--Blake