freebsd-dev/sys/dev/netmap/if_lem_netmap.h
Luigi Rizzo 64ae02c365 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.
2012-02-27 19:05:01 +00:00

358 lines
9.9 KiB
C

/*
* Copyright (C) 2011 Matteo Landi, Luigi Rizzo. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* $FreeBSD$
* $Id: if_lem_netmap.h 10627 2012-02-23 19:37:15Z luigi $
*
* netmap support for "lem"
*
* For details on netmap support please see ixgbe_netmap.h
*/
#include <net/netmap.h>
#include <sys/selinfo.h>
#include <vm/vm.h>
#include <vm/pmap.h> /* vtophys ? */
#include <dev/netmap/netmap_kern.h>
static void
lem_netmap_lock_wrapper(struct ifnet *ifp, int what, u_int ringid)
{
struct adapter *adapter = ifp->if_softc;
/* only one ring here so ignore the ringid */
switch (what) {
case NETMAP_CORE_LOCK:
EM_CORE_LOCK(adapter);
break;
case NETMAP_CORE_UNLOCK:
EM_CORE_UNLOCK(adapter);
break;
case NETMAP_TX_LOCK:
EM_TX_LOCK(adapter);
break;
case NETMAP_TX_UNLOCK:
EM_TX_UNLOCK(adapter);
break;
case NETMAP_RX_LOCK:
EM_RX_LOCK(adapter);
break;
case NETMAP_RX_UNLOCK:
EM_RX_UNLOCK(adapter);
break;
}
}
/*
* Register/unregister
*/
static int
lem_netmap_reg(struct ifnet *ifp, int onoff)
{
struct adapter *adapter = ifp->if_softc;
struct netmap_adapter *na = NA(ifp);
int error = 0;
if (na == NULL)
return EINVAL;
lem_disable_intr(adapter);
/* Tell the stack that the interface is no longer active */
ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
#ifndef EM_LEGACY_IRQ // XXX do we need this ?
taskqueue_block(adapter->tq);
taskqueue_drain(adapter->tq, &adapter->rxtx_task);
taskqueue_drain(adapter->tq, &adapter->link_task);
#endif /* !EM_LEGCY_IRQ */
if (onoff) {
ifp->if_capenable |= IFCAP_NETMAP;
na->if_transmit = ifp->if_transmit;
ifp->if_transmit = netmap_start;
lem_init_locked(adapter);
if ((ifp->if_drv_flags & (IFF_DRV_RUNNING | IFF_DRV_OACTIVE)) == 0) {
error = ENOMEM;
goto fail;
}
} else {
fail:
/* return to non-netmap mode */
ifp->if_transmit = na->if_transmit;
ifp->if_capenable &= ~IFCAP_NETMAP;
lem_init_locked(adapter); /* also enable intr */
}
#ifndef EM_LEGACY_IRQ
taskqueue_unblock(adapter->tq); // XXX do we need this ?
#endif /* !EM_LEGCY_IRQ */
return (error);
}
/*
* Reconcile kernel and user view of the transmit ring.
*/
static int
lem_netmap_txsync(struct ifnet *ifp, u_int ring_nr, int do_lock)
{
struct adapter *adapter = ifp->if_softc;
struct netmap_adapter *na = NA(ifp);
struct netmap_kring *kring = &na->tx_rings[ring_nr];
struct netmap_ring *ring = kring->ring;
u_int j, k, l, n = 0, lim = kring->nkr_num_slots - 1;
/* generate an interrupt approximately every half ring */
int report_frequency = kring->nkr_num_slots >> 1;
/* take a copy of ring->cur now, and never read it again */
k = ring->cur;
if (k > lim)
return netmap_ring_reinit(kring);
if (do_lock)
EM_TX_LOCK(adapter);
bus_dmamap_sync(adapter->txdma.dma_tag, adapter->txdma.dma_map,
BUS_DMASYNC_POSTREAD);
/*
* Process new packets to send. j is the current index in the
* netmap ring, l is the corresponding index in the NIC ring.
*/
j = kring->nr_hwcur;
if (j != k) { /* we have new packets to send */
l = netmap_idx_k2n(kring, j);
for (n = 0; j != k; n++) {
/* slot is the current slot in the netmap ring */
struct netmap_slot *slot = &ring->slot[j];
/* curr is the current slot in the nic ring */
struct e1000_tx_desc *curr = &adapter->tx_desc_base[l];
struct em_buffer *txbuf = &adapter->tx_buffer_area[l];
int flags = ((slot->flags & NS_REPORT) ||
j == 0 || j == report_frequency) ?
E1000_TXD_CMD_RS : 0;
uint64_t paddr;
void *addr = PNMB(slot, &paddr);
u_int len = slot->len;
if (addr == netmap_buffer_base || len > NETMAP_BUF_SIZE) {
if (do_lock)
EM_TX_UNLOCK(adapter);
return netmap_ring_reinit(kring);
}
slot->flags &= ~NS_REPORT;
if (slot->flags & NS_BUF_CHANGED) {
/* buffer has changed, reload map */
netmap_reload_map(adapter->txtag, txbuf->map, addr);
curr->buffer_addr = htole64(paddr);
slot->flags &= ~NS_BUF_CHANGED;
}
curr->upper.data = 0;
curr->lower.data =
htole32( adapter->txd_cmd | len |
(E1000_TXD_CMD_EOP | flags) );
bus_dmamap_sync(adapter->txtag, txbuf->map,
BUS_DMASYNC_PREWRITE);
j = (j == lim) ? 0 : j + 1;
l = (l == lim) ? 0 : l + 1;
}
kring->nr_hwcur = k; /* the saved ring->cur */
kring->nr_hwavail -= n;
bus_dmamap_sync(adapter->txdma.dma_tag, adapter->txdma.dma_map,
BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
E1000_WRITE_REG(&adapter->hw, E1000_TDT(0), l);
}
if (n == 0 || kring->nr_hwavail < 1) {
int delta;
/* record completed transmissions using TDH */
l = E1000_READ_REG(&adapter->hw, E1000_TDH(0));
if (l >= kring->nkr_num_slots) { /* XXX can it happen ? */
D("bad TDH %d", l);
l -= kring->nkr_num_slots;
}
delta = l - adapter->next_tx_to_clean;
if (delta) {
/* some tx completed, increment hwavail. */
if (delta < 0)
delta += kring->nkr_num_slots;
adapter->next_tx_to_clean = l;
kring->nr_hwavail += delta;
}
}
/* update avail to what the kernel knows */
ring->avail = kring->nr_hwavail;
if (do_lock)
EM_TX_UNLOCK(adapter);
return 0;
}
/*
* Reconcile kernel and user view of the receive ring.
*/
static int
lem_netmap_rxsync(struct ifnet *ifp, u_int ring_nr, int do_lock)
{
struct adapter *adapter = ifp->if_softc;
struct netmap_adapter *na = NA(ifp);
struct netmap_kring *kring = &na->rx_rings[ring_nr];
struct netmap_ring *ring = kring->ring;
int j, l, n, lim = kring->nkr_num_slots - 1;
int force_update = do_lock || kring->nr_kflags & NKR_PENDINTR;
u_int k = ring->cur, resvd = ring->reserved;
if (k > lim)
return netmap_ring_reinit(kring);
if (do_lock)
EM_RX_LOCK(adapter);
/* XXX check sync modes */
bus_dmamap_sync(adapter->rxdma.dma_tag, adapter->rxdma.dma_map,
BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
/*
* Import newly received packets into the netmap ring.
* j is an index in the netmap ring, l in the NIC ring.
*/
l = adapter->next_rx_desc_to_check;
j = netmap_idx_n2k(kring, l);
if (netmap_no_pendintr || force_update) {
for (n = 0; ; n++) {
struct e1000_rx_desc *curr = &adapter->rx_desc_base[l];
uint32_t staterr = le32toh(curr->status);
int len;
if ((staterr & E1000_RXD_STAT_DD) == 0)
break;
len = le16toh(curr->length) - 4; // CRC
if (len < 0) {
D("bogus pkt size at %d", j);
len = 0;
}
ring->slot[j].len = len;
bus_dmamap_sync(adapter->rxtag,
adapter->rx_buffer_area[l].map,
BUS_DMASYNC_POSTREAD);
j = (j == lim) ? 0 : j + 1;
l = (l == lim) ? 0 : l + 1;
}
if (n) { /* update the state variables */
adapter->next_rx_desc_to_check = l;
kring->nr_hwavail += n;
}
kring->nr_kflags &= ~NKR_PENDINTR;
}
/* skip past packets that userspace has released */
j = kring->nr_hwcur; /* netmap ring index */
if (resvd > 0) {
if (resvd + ring->avail >= lim + 1) {
D("XXX invalid reserve/avail %d %d", resvd, ring->avail);
ring->reserved = resvd = 0; // XXX panic...
}
k = (k >= resvd) ? k - resvd : k + lim + 1 - resvd;
}
if (j != k) { /* userspace has released some packets. */
l = netmap_idx_k2n(kring, j); /* NIC ring index */
for (n = 0; j != k; n++) {
struct netmap_slot *slot = &ring->slot[j];
struct e1000_rx_desc *curr = &adapter->rx_desc_base[l];
struct em_buffer *rxbuf = &adapter->rx_buffer_area[l];
uint64_t paddr;
void *addr = PNMB(slot, &paddr);
if (addr == netmap_buffer_base) { /* bad buf */
if (do_lock)
EM_RX_UNLOCK(adapter);
return netmap_ring_reinit(kring);
}
if (slot->flags & NS_BUF_CHANGED) {
/* buffer has changed, reload map */
netmap_reload_map(adapter->rxtag, rxbuf->map, addr);
curr->buffer_addr = htole64(paddr);
slot->flags &= ~NS_BUF_CHANGED;
}
curr->status = 0;
bus_dmamap_sync(adapter->rxtag, rxbuf->map,
BUS_DMASYNC_PREREAD);
j = (j == lim) ? 0 : j + 1;
l = (l == lim) ? 0 : l + 1;
}
kring->nr_hwavail -= n;
kring->nr_hwcur = k;
bus_dmamap_sync(adapter->rxdma.dma_tag, adapter->rxdma.dma_map,
BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
/*
* IMPORTANT: we must leave one free slot in the ring,
* so move l back by one unit
*/
l = (l == 0) ? lim : l - 1;
E1000_WRITE_REG(&adapter->hw, E1000_RDT(0), l);
}
/* tell userspace that there are new packets */
ring->avail = kring->nr_hwavail - resvd;
if (do_lock)
EM_RX_UNLOCK(adapter);
return 0;
}
static void
lem_netmap_attach(struct adapter *adapter)
{
struct netmap_adapter na;
bzero(&na, sizeof(na));
na.ifp = adapter->ifp;
na.separate_locks = 1;
na.num_tx_desc = adapter->num_tx_desc;
na.num_rx_desc = adapter->num_rx_desc;
na.nm_txsync = lem_netmap_txsync;
na.nm_rxsync = lem_netmap_rxsync;
na.nm_lock = lem_netmap_lock_wrapper;
na.nm_register = lem_netmap_reg;
netmap_attach(&na, 1);
}
/* end of file */