On 11/07/12 13:51, Raghavendra K T wrote: >>>> Almost all s390 kernels use diag9c (directed yield to a given guest cpu) for spinlocks, though. >>> >>> Perhaps x86 should copy this. >> >> See arch/s390/lib/spinlock.c >> The basic idea is using several heuristics: >> - loop for a given amount of loops >> - check if the lock holder is currently scheduled by the hypervisor >> (smp_vcpu_scheduled, which uses the sigp sense running instruction) >> Dont know if such thing is available for x86. It must be a lot cheaper >> than a guest exit to be useful > > Unfortunately we do not have information on lock-holder. That would be an independent patch and requires guest changes. -- 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
