On 04/03/2012 08:24 PM, Jan Kiszka wrote: > > > >>> > >>> A performance note: delivering an interrupt needs to search all vcpus > >>> for an APIC ID match. The previous plan was to cache (or pre-calculate) > >>> this lookup in the irq routing table. Now it looks like we'll need a > >>> separate cache for this. > >> > >> As this is non-existent until today, we don't regress here. And it can > >> still be added on top later on, transparently. > > > > Yes, it's just a note, not an objection. The cache lookup will be > > slower than the gsi lookup (hash table vs. array) but still O(1) vs. the > > current O(n). > > If you are concerned about performance in this path, wouldn't a DMA > interface for MSI injection be counterproductive? Yes, it would. The lack of coalescing reporting support is also problematic. I just mentioned this idea as food for thought. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain. -- 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
