On 04/09/2015 10:13 AM, Peter Zijlstra wrote: > On Thu, Apr 09, 2015 at 09:16:24AM -0400, Rik van Riel wrote: >> 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? > > Well use paravirt, !paravirt stuff sucks performance wise anyhow. > > The question really is: is the added complexity worth the maintenance > burden. And I'm just not convinced !paravirt virt is a performance > critical target. Fair enough. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
