Forum Discussion

fmartos_30060's avatar
fmartos_30060
Icon for Nimbostratus rankNimbostratus
Jul 27, 2010

High CPU usage?

Hi,

 

 

one of our ASM biggest customer is worried about the performance of his new LTM + ASM machine. They own a pair of 6900 running 9.4.8.HF4 with LTM + ASM (full of licensed capabilities). And what they can see in performance graphics is almost (always) a baseline of 50% cpu usage for CPU00, CPU01 and CPU02 (CPU03 is 100% by TMM, that's normal). If we have a look at CPU usage with top we can see the following:

 

 

3 bd processes, 2 running in CPU 1 and 2 in CPU 2, using 12.2% CPU. TMM running in CPU 3 is using 25% of CPU (normal), mysqld is just using 01% of CPU... As I can see it, there is no justification for that 50% that is always shown in performance graphics.

 

 

The machine has a baseline of 3K HTTP connections with peaks of 5K. New connections has a baseline of 200 each second with peaks of 500. SSL transactions are 200 per second, with peaks of 300.

 

 

CPU usage graphics show 50% of constant usage with peaks of 70% (matching new connections and HTTP transactions peaks).

 

 

ASM CPU utilization graphics show 12% of constant CPU usage, with peaks of 20% (matching the other peaks).

 

 

As I can see it, maybe just system CPU usage (showed by top as 16-23% for the 3 CPU) is a little high, but the customer is not sure.

 

 

Any appreciation?

 

application delivery
design
performance
testing
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Jul 28, 2010
    Hi,

     

     

    I'd suggest opening a case with F5 Support. I'd be quite interested in hearing what they have to say on this as I've always found it difficult to get any concrete information on what ASM is doing with its CPU cycles and memory.

     

     

    If you get anything useful on this from F5 or otherwise, could you reply back?

     

     

    A small note: I believe the ASM CPU utilization graph doesn't show cumulative stats for ASM CPU usage--just the amount of CPU used by the BD process(es). Also, I think the top output should show a percentage of all CPU's. So if a single BD process is using 10% of all CPU per top, it's actually 40% of a single CPU as BD can't run across multiple CPUs (or CPU cores).

     

     

    Thanks, Aaron
  • fmartos_30060's avatar
    fmartos_30060
    Icon for Nimbostratus rankNimbostratus
    Jul 29, 2010
    Hi,

     

     

    I opened the case... Based on my experience, medium (25%) sustained CPU loads are not rare on devices using ASM, with not too high traffic loads. 50% looks something strange, although I think v.9.4.8 has something to do with that... I know in v.10.2 ASM performance has been greatly improved.

     

     

    I hope support would tell me where to look to solve this issue. I'll get back if I find a solution.