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MFC r281764, r282563: Disable RX/TX queues notifications when not needed.

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This reduces CPU load and doubles iperf throughput, reaching 2-3Gbit/s.

Sponsored by:	iXsystems, Inc.
This commit is contained in:
mav 2015-05-13 10:18:44 +00:00
parent 645e8cf00d
commit f24af427aa
1 changed files with 14 additions and 13 deletions
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27
usr.sbin/bhyve/pci_virtio_net.c
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@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$");
#include <sys/select.h>
#include <sys/uio.h>
#include <sys/ioctl.h>
#include <machine/atomic.h>
#include <net/ethernet.h>
#include <errno.h>
@ -393,6 +394,7 @@ pci_vtnet_ping_rxq(void *vsc, struct vqueue_info *vq)
*/
if (sc->vsc_rx_ready == 0) {
sc->vsc_rx_ready = 1;
vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY;
}
}
@ -438,6 +440,7 @@ pci_vtnet_ping_txq(void *vsc, struct vqueue_info *vq)
/* Signal the tx thread for processing */
pthread_mutex_lock(&sc->tx_mtx);
vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY;
if (sc->tx_in_progress == 0)
pthread_cond_signal(&sc->tx_cond);
pthread_mutex_unlock(&sc->tx_mtx);
@ -451,7 +454,7 @@ pci_vtnet_tx_thread(void *param)
{
struct pci_vtnet_softc *sc = param;
struct vqueue_info *vq;
int have_work, error;
int error;
vq = &sc->vsc_queues[VTNET_TXQ];
@ -465,19 +468,17 @@ pci_vtnet_tx_thread(void *param)
for (;;) {
/* note - tx mutex is locked here */
do {
if (sc->resetting)
have_work = 0;
else
have_work = vq_has_descs(vq);
while (sc->resetting || !vq_has_descs(vq)) {
vq->vq_used->vu_flags &= ~VRING_USED_F_NO_NOTIFY;
mb();
if (!sc->resetting && vq_has_descs(vq))
break;
if (!have_work) {
sc->tx_in_progress = 0;
error = pthread_cond_wait(&sc->tx_cond,
&sc->tx_mtx);
assert(error == 0);
}
} while (!have_work);
sc->tx_in_progress = 0;
error = pthread_cond_wait(&sc->tx_cond, &sc->tx_mtx);
assert(error == 0);
}
vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY;
sc->tx_in_progress = 1;
pthread_mutex_unlock(&sc->tx_mtx);