On Fri, Sep 11, 2015 at 02:37:38PM -0400, Waiman Long wrote: > In an overcommitted guest where some vCPUs have to be halted to make > forward progress in other areas, it is highly likely that a vCPU later > in the spinlock queue will be spinning while the ones earlier in the > queue would have been halted. The spinning in the later vCPUs is then > just a waste of precious CPU cycles because they are not going to > get the lock soon as the earlier ones have to be woken up and take > their turn to get the lock. > > This patch implements an adaptive spinning mechanism where the vCPU > will call pv_wait() if the following conditions are true: > > 1) the vCPU has not been halted before; > 2) the previous vCPU is not running.
Why 1? For the mutex adaptive stuff we only care about the lock holder running, right? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
