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IanGrant_329505's avatar
IanGrant_329505
Icon for Nimbostratus rankNimbostratus
Jan 15, 2018

Identifying cause of high CPU

Hi,

 

We're seeing a large increase in CPU on our version 10.2.4 LTM devices. When we look at top on the boxes tmm is the cause and it's significantly higher on one of the core's - 60% on 1 as opposed to 20% on 0 - than the other. If there any way of identifying what's causing increase? This rise has coincided with an increase in throughput. Is there anyway of identifying which irule for ssl offload (as an example) are using the most cpu?

 

BIG-IP
devops
LTM

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  • Carl_Brothers's avatar
    Carl_Brothers
    Icon for Employee rankEmployee
    Jan 15, 2018

    Ian, Some more info on CMP can be found here and there are some commands to see if there are any virtuals that have CMP disabled. - https://support.f5.com/csp/article/K7751

     

    When traffic increases, you will likely see an impact from additional SSL and compression being done on the platform. If there is not a compression or enterprise license on the older platform then the Compression is likely not being done in the chips designed for that, so that is eating CPU cycles.

     

    Also SSL is moving to more modern ciphers which the older platforms cannot do in hardware, so it may not matter if you have an advanced SSL throughput license that would unlock the SSL Hardware on the platform.

     

    If your system is still under a valid support contract, please consider upgrading as this code base is approaching its sixth birthday and is no longer supported. EOTS(End of Technical Support) for 10.2.4 was 31 Dec 2016.

     

    To see what versions of code are compatible with your platform check out this article and try to get to a version that still has some time on the support clock - https://support.f5.com/csp/article/K9412

     

    If you have never done an upgrade before, or even if you have, I encourage all to read this document that covers the upgrade procedure. - https://support.f5.com/csp/article/K84554955

     

    HTH,

     

    Carl B.

     

  • IanGrant_329505's avatar
    IanGrant_329505
    Icon for Nimbostratus rankNimbostratus
    Jan 15, 2018

    Hi Carl,

     

    I've ran the cmp mode show command on our virtual servers and all are reporting using cmp.

     

    I've checked the cipher used for one of the busiest virtual servers with using a client SSL profile and according to the documentation for a 6400 running 10.2.4, this should use hardware acceleration.

     

    Unfortunately our servers are no longer in support. We are in the process of upgrading these to Viprions, but unfortunately this isn't a trivial task.

     

    Regards Ian