13 Replies Latest reply on Sep 21, 2015 5:17 AM by Carlos_A

    Questions regarding QAT

    lbeliveau Green Belt



      I have installed and configured a Colleto Creek PCI card (DH 8955) in SR-IOV mode.


      I was able to run the sample applications within virtual machine over kvm and it works fine.


      Following are two questions that I’m trying to figure out.  Hopefully someone can help me.


      1) It appears that it is not possible to configure the number of VFs on those devices (this is possible for Niantic NICs).  How does the multiple hardware engines are shared between virtual machines ?  Is there a queuing mechanism that allow some kind of quality of service ?  Does the maximum throughput that can achieve a virtual machine is dependent on the number of VFs used by other virtual machines ?


      2) A somewhat related question, it seems that in SR-IOV guest mode, the guest is responsible to configure it’s access to the hardware accelerator (see /etc/ dh895xcc_qa_dev0.conf).  Is there a way for the host to restrict the access to the hardware for a given virtual machine (most likely by means of the VFs) ?  In a multi-tenant environment, it might be desirable to provide deterministic throughput/delay to a given virtual machine when concurrent virtual machines are sharing the same device.


      Thanks a lot !


      Best regards,