Re: [PATCH v2 4/6] KVM-GST: KVM Steal time registration

From: Avi Kivity
Date: Sun Jan 30 2011 - 08:16:42 EST

On 01/28/2011 09:52 PM, Glauber Costa wrote:
Register steal time within KVM. Everytime we sample the steal time
information, we update a local variable that tells what was the
last time read. We then account the difference.

static void kvm_guest_cpu_offline(void *dummy)
+ native_write_msr(MSR_KVM_STEAL_TIME, 0, 0);

Don't use the native_ versions, they override the pvops implementation. It doesn't matter for kvm, but we're not supposed to know this.

+ /*
+ * using nanoseconds introduces noise, which accumulates easily
+ * leading to big steal time values. We want, however, to keep the
+ * interface nanosecond-based for future-proofness. The hypervisor may
+ * adopt a similar strategy, but we can't rely on that.
+ */
+ delta /= NSEC_PER_MSEC;
+ delta *= NSEC_PER_MSEC;

You're working around this problem both in the guest and host. So even if we fix it in one, it will still be broken in the other.

+ return delta;

error compiling committee.c: too many arguments to function

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