A bunch of netmap fixes:

USERSPACE:
1. add support for devices with different number of rx and tx queues;

2. add better support for zero-copy operation, adding an extra field
   to the netmap ring to indicate how many buffers we have already processed
   but not yet released (with help from Eddie Kohler);

3. The two changes above unfortunately require an API change, so while
   at it add a version field and some spares to the ioctl() argument
   to help detect mismatches.

4. update the manual page for the two changes above;

5. update sample applications in tools/tools/netmap

KERNEL:

1. simplify the internal structures moving the global wait queues
   to the 'struct netmap_adapter';

2. simplify the functions that map kring<->nic ring indexes

3. normalize device-specific code, helps mainteinance;

4. start exploring the impact of micro-optimizations (prefetch etc.)
   in the ixgbe driver.
   Use 'legacy' descriptors on the tx ring and prefetch slots gives
   about 20% speedup at 900 MHz. Another 7-10% would come from removing
   the explict calls to bus_dmamap* in the core (they are effectively
   NOPs in this case, but it takes expensive load of the per-buffer
   dma maps to figure out that they are all NULL.

   Rx performance not investigated.

I am postponing the MFC so i can import a few more improvements
before merging.

1 files changed, 5 insertions, 4 deletions

diff --git a/sys/dev/e1000/if_em.c b/sys/dev/e1000/if_em.c
index 9495c79..8ab511d 100644
--- a/sys/dev/e1000/if_em.c
+++ b/sys/dev/e1000/if_em.c
@@ -3296,7 +3296,7 @@ em_setup_transmit_ring(struct tx_ring *txr)
 		}
 #ifdef DEV_NETMAP
 		if (slot) {
-			int si = netmap_tidx_n2k(na, txr->me, i);
+			int si = netmap_idx_n2k(&na->tx_rings[txr->me], i);
 			uint64_t paddr;
 			void *addr;
 
@@ -3759,7 +3759,7 @@ em_txeof(struct tx_ring *txr)
 		selwakeuppri(&na->tx_rings[txr->me].si, PI_NET);
 		EM_TX_UNLOCK(txr);
 		EM_CORE_LOCK(adapter);
-		selwakeuppri(&na->tx_rings[na->num_queues + 1].si, PI_NET);
+		selwakeuppri(&na->tx_si, PI_NET);
 		EM_CORE_UNLOCK(adapter);
 		EM_TX_LOCK(txr);
 		return (FALSE);
@@ -4051,7 +4051,7 @@ em_setup_receive_ring(struct rx_ring *rxr)
 		rxbuf = &rxr->rx_buffers[j];
 #ifdef DEV_NETMAP
 		if (slot) {
-			int si = netmap_ridx_n2k(na, rxr->me, j);
+			int si = netmap_idx_n2k(&na->rx_rings[rxr->me], j);
 			uint64_t paddr;
 			void *addr;
 
@@ -4370,10 +4370,11 @@ em_rxeof(struct rx_ring *rxr, int count, int *done)
 	if (ifp->if_capenable & IFCAP_NETMAP) {
 		struct netmap_adapter *na = NA(ifp);
 
+		na->rx_rings[rxr->me].nr_kflags |= NKR_PENDINTR;
 		selwakeuppri(&na->rx_rings[rxr->me].si, PI_NET);
 		EM_RX_UNLOCK(rxr);
 		EM_CORE_LOCK(adapter);
-		selwakeuppri(&na->rx_rings[na->num_queues + 1].si, PI_NET);
+		selwakeuppri(&na->rx_si, PI_NET);
 		EM_CORE_UNLOCK(adapter);
 		return (0);
 	}