EPT-D CPU feature gives excellent Terminal Server performance in VM

Noticed that performance of virtual terminal servers was poor running on HP DL580 G5 servers (4 x 3GHz Intel CPUs, bought May 2008) with ESX 3.5/vSphere 4.0.

Noticed that Performance was excellent when running on Dell R710 with 2 x Intel X5560 (Nehalem) CPUs. Turns out that this is less to do with XenServer and more to do with the EPT-D function present in the X5560 CPUs. The XenApp optimisation setting for VMs within XenServer is effectively a software implementation of this EPT-D function. AMD have an equivalent feature called RVI.

See Virtual Reality Check Phase II for more info.

Thus I would say that for acceptable virtual Terminal Server performance (i.e. not noticably different from running on physical servers) you really need this CPU feature present.

This entry was posted in Hardware, vSphere, XenApp, XenServer. Bookmark the permalink.

2 Responses to EPT-D CPU feature gives excellent Terminal Server performance in VM

  1. rcmtech says:

    I should point out that I’ve not tested AMDs RVI feature, so whilst it is apparently equivalent I’ve not seen it in action myself. Would be interesting to hear from anyone who has tried it.

  2. rcmtech says:

    Just found these two (very similar) PDFs that explain how EPT and RVI work, and give details on the performance improvements VMWare experienced.
    http://www.vmware.com/pdf/Perf_ESX_Intel-EPT-eval.pdf
    http://www.vmware.com/pdf/RVI_performance.pdf

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s