Messages in this thread | | | Subject | RE: [RFC PATCH 2/2] macvtap: TX zero copy between guest and host kernel | From | Shirley Ma <> | Date | Tue, 14 Sep 2010 19:40:52 -0700 |
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On Wed, 2010-09-15 at 09:50 +0800, Xin, Xiaohui wrote: > I think what David said is what we have thought before in mp device. > Since we are not sure the exact time the tx buffer was wrote though > DMA operation. > But the deadline is when the tx buffer was freed. So we only notify > the vhost stuff > about the write when tx buffer freed. But the deadline is maybe too > late for performance.
Have you tried it? If so what's the performance penalty you have seen by notifying vhost when tx buffer freed?
I am thinking to have a callback in skb destructor, vhost_add_used_and_signal gets updated when skb is actually freed, vhost vq & head need to be passed to the callback. This might requires vhost ring size is at least as big as the lower device driver.
Thanks Shirley
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