"Michael S. Tsirkin" <mst@xxxxxxxxxx> writes: > On Tue, Feb 10, 2015 at 12:02:37PM +1030, Rusty Russell wrote: >> Jason Wang <jasowang@xxxxxxxxxx> writes: >> > This patch enables the interrupt coalescing setting through ethtool. >> >> The problem is that there's nothing network specific about interrupt >> coalescing. I can see other devices wanting exactly the same thing, >> which means we'd deprecate this in the next virtio standard. >> >> I think the right answer is to extend like we did with >> vring_used_event(), eg: >> >> 1) Add a new feature VIRTIO_F_RING_COALESCE. >> 2) Add another a 32-bit field after vring_used_event(), eg: >> #define vring_used_delay(vr) (*(u32 *)((vr)->avail->ring[(vr)->num + 2])) >> >> This loses the ability to coalesce by number of frames, but we can still >> do number of sg entries, as we do now with used_event, and we could >> change virtqueue_enable_cb_delayed() to take a precise number if we >> wanted. > > But do we expect delay to be update dynamically? > If not, why not stick it in config space? Hmm, we could update it dynamically (and will, in the case of ethtool). But it won't be common, so we could append a field to virtio_pci_common_cfg for PCI. I think MMIO and CCW would be easy to extend too, but CC'd to check. >> My feeling is that this should be a v1.0-only feature though >> (eg. feature bit 33). > > Yes, e.g. we can't extend config space for legacy virtio pci. Thanks, Rusty. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
