numam-dpdk/drivers/net/virtio/virtqueue.c
Joyce Kong ea5207c158 virtio: use one way barrier for split vring used index
In case VIRTIO_F_ORDER_PLATFORM(36) is not negotiated, then the frontend
and backend are assumed to be implemented in software, that is they can
run on identical CPUs in an SMP configuration.
Thus a weak form of memory barriers like rte_smp_r/wmb, other than
rte_cio_r/wmb, is sufficient for this case(vq->hw->weak_barriers == 1)
and yields better performance.
For the above case, this patch helps yielding even better performance
by replacing the two-way barriers with C11 one-way barriers for used
index in split ring.

Signed-off-by: Joyce Kong <joyce.kong@arm.com>
Reviewed-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
2020-05-05 15:54:26 +02:00

216 lines
5.0 KiB
C

/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2010-2015 Intel Corporation
*/
#include <stdint.h>
#include <rte_mbuf.h>
#include "virtqueue.h"
#include "virtio_logs.h"
#include "virtio_pci.h"
#include "virtio_rxtx_simple.h"
/*
* Two types of mbuf to be cleaned:
* 1) mbuf that has been consumed by backend but not used by virtio.
* 2) mbuf that hasn't been consued by backend.
*/
struct rte_mbuf *
virtqueue_detach_unused(struct virtqueue *vq)
{
struct rte_mbuf *cookie;
struct virtio_hw *hw;
uint16_t start, end;
int type, idx;
if (vq == NULL)
return NULL;
hw = vq->hw;
type = virtio_get_queue_type(hw, vq->vq_queue_index);
start = vq->vq_avail_idx & (vq->vq_nentries - 1);
end = (vq->vq_avail_idx + vq->vq_free_cnt) & (vq->vq_nentries - 1);
for (idx = 0; idx < vq->vq_nentries; idx++) {
if (hw->use_vec_rx && !vtpci_packed_queue(hw) &&
type == VTNET_RQ) {
if (start <= end && idx >= start && idx < end)
continue;
if (start > end && (idx >= start || idx < end))
continue;
cookie = vq->sw_ring[idx];
if (cookie != NULL) {
vq->sw_ring[idx] = NULL;
return cookie;
}
} else {
cookie = vq->vq_descx[idx].cookie;
if (cookie != NULL) {
vq->vq_descx[idx].cookie = NULL;
return cookie;
}
}
}
return NULL;
}
/* Flush used descs */
static void
virtqueue_rxvq_flush_packed(struct virtqueue *vq)
{
struct vq_desc_extra *dxp;
uint16_t i;
struct vring_packed_desc *descs = vq->vq_packed.ring.desc;
int cnt = 0;
i = vq->vq_used_cons_idx;
while (desc_is_used(&descs[i], vq) && cnt++ < vq->vq_nentries) {
dxp = &vq->vq_descx[descs[i].id];
if (dxp->cookie != NULL) {
rte_pktmbuf_free(dxp->cookie);
dxp->cookie = NULL;
}
vq->vq_free_cnt++;
vq->vq_used_cons_idx++;
if (vq->vq_used_cons_idx >= vq->vq_nentries) {
vq->vq_used_cons_idx -= vq->vq_nentries;
vq->vq_packed.used_wrap_counter ^= 1;
}
i = vq->vq_used_cons_idx;
}
}
/* Flush the elements in the used ring. */
static void
virtqueue_rxvq_flush_split(struct virtqueue *vq)
{
struct virtnet_rx *rxq = &vq->rxq;
struct virtio_hw *hw = vq->hw;
struct vring_used_elem *uep;
struct vq_desc_extra *dxp;
uint16_t used_idx, desc_idx;
uint16_t nb_used, i;
nb_used = virtqueue_nused(vq);
for (i = 0; i < nb_used; i++) {
used_idx = vq->vq_used_cons_idx & (vq->vq_nentries - 1);
uep = &vq->vq_split.ring.used->ring[used_idx];
if (hw->use_vec_rx) {
desc_idx = used_idx;
rte_pktmbuf_free(vq->sw_ring[desc_idx]);
vq->vq_free_cnt++;
} else if (hw->use_inorder_rx) {
desc_idx = (uint16_t)uep->id;
dxp = &vq->vq_descx[desc_idx];
if (dxp->cookie != NULL) {
rte_pktmbuf_free(dxp->cookie);
dxp->cookie = NULL;
}
vq_ring_free_inorder(vq, desc_idx, 1);
} else {
desc_idx = (uint16_t)uep->id;
dxp = &vq->vq_descx[desc_idx];
if (dxp->cookie != NULL) {
rte_pktmbuf_free(dxp->cookie);
dxp->cookie = NULL;
}
vq_ring_free_chain(vq, desc_idx);
}
vq->vq_used_cons_idx++;
}
if (hw->use_vec_rx) {
while (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
virtio_rxq_rearm_vec(rxq);
if (virtqueue_kick_prepare(vq))
virtqueue_notify(vq);
}
}
}
/* Flush the elements in the used ring. */
void
virtqueue_rxvq_flush(struct virtqueue *vq)
{
struct virtio_hw *hw = vq->hw;
if (vtpci_packed_queue(hw))
virtqueue_rxvq_flush_packed(vq);
else
virtqueue_rxvq_flush_split(vq);
}
int
virtqueue_rxvq_reset_packed(struct virtqueue *vq)
{
int size = vq->vq_nentries;
struct vq_desc_extra *dxp;
struct virtnet_rx *rxvq;
uint16_t desc_idx;
vq->vq_used_cons_idx = 0;
vq->vq_desc_head_idx = 0;
vq->vq_avail_idx = 0;
vq->vq_desc_tail_idx = (uint16_t)(vq->vq_nentries - 1);
vq->vq_free_cnt = vq->vq_nentries;
vq->vq_packed.used_wrap_counter = 1;
vq->vq_packed.cached_flags = VRING_PACKED_DESC_F_AVAIL;
vq->vq_packed.event_flags_shadow = 0;
vq->vq_packed.cached_flags |= VRING_DESC_F_WRITE;
rxvq = &vq->rxq;
memset(rxvq->mz->addr, 0, rxvq->mz->len);
for (desc_idx = 0; desc_idx < vq->vq_nentries; desc_idx++) {
dxp = &vq->vq_descx[desc_idx];
if (dxp->cookie != NULL) {
rte_pktmbuf_free(dxp->cookie);
dxp->cookie = NULL;
}
}
vring_desc_init_packed(vq, size);
return 0;
}
int
virtqueue_txvq_reset_packed(struct virtqueue *vq)
{
int size = vq->vq_nentries;
struct vq_desc_extra *dxp;
struct virtnet_tx *txvq;
uint16_t desc_idx;
vq->vq_used_cons_idx = 0;
vq->vq_desc_head_idx = 0;
vq->vq_avail_idx = 0;
vq->vq_desc_tail_idx = (uint16_t)(vq->vq_nentries - 1);
vq->vq_free_cnt = vq->vq_nentries;
vq->vq_packed.used_wrap_counter = 1;
vq->vq_packed.cached_flags = VRING_PACKED_DESC_F_AVAIL;
vq->vq_packed.event_flags_shadow = 0;
txvq = &vq->txq;
memset(txvq->mz->addr, 0, txvq->mz->len);
memset(txvq->virtio_net_hdr_mz->addr, 0,
txvq->virtio_net_hdr_mz->len);
for (desc_idx = 0; desc_idx < vq->vq_nentries; desc_idx++) {
dxp = &vq->vq_descx[desc_idx];
if (dxp->cookie != NULL) {
rte_pktmbuf_free(dxp->cookie);
dxp->cookie = NULL;
}
}
vring_desc_init_packed(vq, size);
return 0;
}