95c517c09b
If we track how many buffers we've used, we can tell whether we really need to interrupt the Guest. This happens as a side effect of spurious notifications. Spurious notifications happen because it can take a while before the Host thread wakes up and sets the VRING_USED_F_NO_NOTIFY flag, and meanwhile the Guest can more notifications. A real fix would be to use wake counts, rather than a suppression flag, but the practical difference is generally in the noise: the interrupt is usually coalesced into a pending one anyway so we just save a system call which isn't clearly measurable. Secs Spurious IRQS 1G TCP Guest->Host: 3.93 58 1M normal pings: 100 72 1M 1k pings (-l 120): 57 492904 Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> |
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| .gitignore | ||
| extract | ||
| lguest.c | ||
| lguest.txt | ||
| Makefile | ||