Homework: Spin Lock Alternatives

Submit two items to the the submission web site:

Submit your own question about the paper (e.g., what you find most confusing about the paper or the paper's general context/problem) before lecture (1pm). You cannot use the question below. To the extent possible, during lecture we will try to answer questions submitted the evening before.
Submit your answer for the question below before the beginning of the lecture

Answer the following question: The ticket lock is slightly different than the spinlock in xv6. Assuming an invalidation-based coherence scheme as described in the paper, does a ticket lock introduce less inter-CPU communication than a xv6 spinlock?