On 04/09/2015 03:01 AM, Peter Zijlstra wrote: > On Wed, Apr 08, 2015 at 02:32:19PM -0400, Waiman Long wrote: >> For a virtual guest with the qspinlock patch, a simple unfair byte lock >> will be used if PV spinlock is not configured in or the hypervisor >> isn't either KVM or Xen. The byte lock works fine with small guest >> of just a few vCPUs. On a much larger guest, however, byte lock can >> have serious performance problem. > > Who cares? There are some people out there running guests with dozens of vCPUs. If the code exists to make those setups run better, is there a good reason not to use it? Having said that, only KVM and Xen seem to support very large guests, and PV spinlock is available there. I believe both VMware and Hyperv have a 32 VCPU limit, anyway. -- All rights reversed -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
