<div dir="ltr"><div class="im" style="font-family:arial,sans-serif;font-size:13px"><span style="color:rgb(34,34,34);font-family:arial;font-size:small">Hi,</span></div><div class="im" style="font-family:arial,sans-serif;font-size:13px">

<span style="color:rgb(34,34,34);font-family:arial;font-size:small"><br></span></div><div class="im"><font color="#222222">The use cases fro CPU pinning are exactly like discussed above: (1) lowering guest scheduling latencies and (2) improving networking latencies by pinning the SR-IOV IRQ's to specific cores. There is also a third use case, (3) avoiding long latencies with spinlocks.</font></div>

<div class="im" style="font-family:arial,sans-serif;font-size:13px"><br></div><div class="im" style="font-family:arial,sans-serif;font-size:13px"><span style="color:rgb(34,34,34);font-family:arial;font-size:small">> On Wed, Nov 13, 2013 at 8:20 PM, Jiang, Yunhong </span><span dir="ltr" style="color:rgb(34,34,34);font-family:arial;font-size:small"><<a href="mailto:yunhong.jiang@intel.com" target="_blank">yunhong.jiang@intel.com</a>></span><span style="color:rgb(34,34,34);font-family:arial;font-size:small"> wrote:</span><br style="color:rgb(34,34,34);font-family:arial;font-size:small">

<blockquote class="gmail_quote" style="color:rgb(34,34,34);font-family:arial;font-size:small;margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class="">

</div></blockquote></div><div class="im" style="font-family:arial,sans-serif;font-size:13px"><br></div><div class="im" style="font-family:arial,sans-serif;font-size:13px">>> Similarly, once you start talking about doing SR-IOV networking I/O<br>

>> passthrough into a guest (for SDN/NFV stuff) for optimum efficiency it<br>>> is beneficial to be able to steer interrupts on the physical host to the<br>>> specific cpus on which the guest will be running.  This implies some<br>

>> form of pinning.<br><br></div><span style="font-family:arial,sans-serif;font-size:13px">> Still, I think hypervisor should achieve this, instead of openstack.</span><br><div class="gmail_extra"><br>How would this work? As a solution, this would be much better since then OpenStack would have much less low-level work to do. </div>

<div class="gmail_extra"><br></div><div class="gmail_extra">-Tapio </div><div class="gmail_extra"><br></div></div>