Re: [monit] Quad Core Monitoring

[Scott Silva]

on 5-2-2008 2:10 PM Martin Pala spake the following:
> As mentioned ... monit watches the CPU resources of the whole system 
> (sum of all cores/CPUs), it's not possible to monitor particular core/CPU.
>
> Monitoring single core doesn't make sense i think, since on timesharing 
> system without mentioned resource management can any process run on any 
> CPU. Scheduler can switch the process/thread to any core. If your mysql 
> has multiple threads (almost certainly has), it's not running on one 
> core unless you use resource management to dedicate part of the HW.
>
> Why do you need to watch single core on SMP system? It's like watching 
> single DIMM usage ... your mysql process can be migrated to any core, if 
> you'll define the CPU usage as 25%, it corresponds to eating CPU 
> resources corresponding to one core on 4-core system.
>
>
> Martin
I see his point. If all four cores are running at say 40 or 50%, while 
perfectly valid usage on a busy system, it would trigger on the "25%" test and 
restart mysql for nothing.

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