Rusty Russell
2015-Feb-10 01:32 UTC
[PATCH RFC v5 net-next 4/6] virtio-net: add basic interrupt coalescing support
Jason Wang <jasowang at redhat.com> 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. My feeling is that this should be a v1.0-only feature though (eg. feature bit 33). Cheers, Rusty.> Cc: Rusty Russell <rusty at rustcorp.com.au> > Cc: Michael S. Tsirkin <mst at redhat.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/net/virtio_net.c | 67 +++++++++++++++++++++++++++++++++++++++++ > include/uapi/linux/virtio_net.h | 12 ++++++++ > 2 files changed, 79 insertions(+) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index cc5f5de..2b958fb 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -145,6 +145,11 @@ struct virtnet_info { > > /* Budget for polling tx completion */ > u32 tx_work_limit; > + > + __u32 rx_coalesce_usecs; > + __u32 rx_max_coalesced_frames; > + __u32 tx_coalesce_usecs; > + __u32 tx_max_coalesced_frames; > }; > > struct padded_vnet_hdr { > @@ -1404,12 +1409,73 @@ static void virtnet_get_channels(struct net_device *dev, > channels->other_count = 0; > } > > +static int virtnet_set_coalesce(struct net_device *dev, > + struct ethtool_coalesce *ec) > +{ > + struct virtnet_info *vi = netdev_priv(dev); > + struct scatterlist sg; > + struct virtio_net_ctrl_coalesce c; > + > + if (!vi->has_cvq || > + !virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_COALESCE)) > + return -EOPNOTSUPP; > + if (vi->rx_coalesce_usecs != ec->rx_coalesce_usecs || > + vi->rx_max_coalesced_frames != ec->rx_max_coalesced_frames) { > + c.coalesce_usecs = ec->rx_coalesce_usecs; > + c.max_coalesced_frames = ec->rx_max_coalesced_frames; > + sg_init_one(&sg, &c, sizeof(c)); > + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_COALESCE, > + VIRTIO_NET_CTRL_COALESCE_RX_SET, > + &sg)) { > + dev_warn(&dev->dev, "Fail to set rx coalescing\n"); > + return -EINVAL; > + } > + vi->rx_coalesce_usecs = ec->rx_coalesce_usecs; > + vi->rx_max_coalesced_frames = ec->rx_max_coalesced_frames; > + } > + > + if (vi->tx_coalesce_usecs != ec->tx_coalesce_usecs || > + vi->tx_max_coalesced_frames != ec->tx_max_coalesced_frames) { > + c.coalesce_usecs = ec->tx_coalesce_usecs; > + c.max_coalesced_frames = ec->tx_max_coalesced_frames; > + sg_init_one(&sg, &c, sizeof(c)); > + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_COALESCE, > + VIRTIO_NET_CTRL_COALESCE_TX_SET, > + &sg)) { > + dev_warn(&dev->dev, "Fail to set tx coalescing\n"); > + return -EINVAL; > + } > + vi->tx_coalesce_usecs = ec->tx_coalesce_usecs; > + vi->tx_max_coalesced_frames = ec->tx_max_coalesced_frames; > + } > + > + vi->tx_work_limit = ec->tx_max_coalesced_frames_irq; > + > + return 0; > +} > + > +static int virtnet_get_coalesce(struct net_device *dev, > + struct ethtool_coalesce *ec) > +{ > + struct virtnet_info *vi = netdev_priv(dev); > + > + ec->rx_coalesce_usecs = vi->rx_coalesce_usecs; > + ec->rx_max_coalesced_frames = vi->rx_max_coalesced_frames; > + ec->tx_coalesce_usecs = vi->tx_coalesce_usecs; > + ec->tx_max_coalesced_frames = vi->tx_max_coalesced_frames; > + ec->tx_max_coalesced_frames_irq = vi->tx_work_limit; > + > + return 0; > +} > + > static const struct ethtool_ops virtnet_ethtool_ops = { > .get_drvinfo = virtnet_get_drvinfo, > .get_link = ethtool_op_get_link, > .get_ringparam = virtnet_get_ringparam, > .set_channels = virtnet_set_channels, > .get_channels = virtnet_get_channels, > + .set_coalesce = virtnet_set_coalesce, > + .get_coalesce = virtnet_get_coalesce, > }; > > #define MIN_MTU 68 > @@ -2048,6 +2114,7 @@ static unsigned int features[] = { > VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, > VIRTIO_NET_F_CTRL_MAC_ADDR, > VIRTIO_F_ANY_LAYOUT, > + VIRTIO_NET_F_CTRL_COALESCE, > }; > > static struct virtio_driver virtio_net_driver = { > diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h > index b5f1677..332009d 100644 > --- a/include/uapi/linux/virtio_net.h > +++ b/include/uapi/linux/virtio_net.h > @@ -34,6 +34,7 @@ > /* The feature bitmap for virtio net */ > #define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */ > #define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */ > +#define VIRTIO_NET_F_CTRL_COALESCE 3 /* Set coalescing */ > #define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */ > #define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */ > #define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */ > @@ -202,4 +203,15 @@ struct virtio_net_ctrl_mq { > #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN 1 > #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX 0x8000 > > +struct virtio_net_ctrl_coalesce { > + __u32 coalesce_usecs; > + __u32 max_coalesced_frames; > +}; > + > +#define VIRTIO_NET_CTRL_COALESCE 6 > + #define VIRTIO_NET_CTRL_COALESCE_TX_SET 0 > + #define VIRTIO_NET_CTRL_COALESCE_TX_GET 1 > + #define VIRTIO_NET_CTRL_COALESCE_RX_SET 2 > + #define VIRTIO_NET_CTRL_COALESCE_RX_GET 3 > + > #endif /* _LINUX_VIRTIO_NET_H */ > -- > 1.8.3.1
Jason Wang
2015-Feb-10 06:51 UTC
[PATCH RFC v5 net-next 4/6] virtio-net: add basic interrupt coalescing support
On Tue, Feb 10, 2015 at 9:32 AM, Rusty Russell <rusty at rustcorp.com.au> wrote:> Jason Wang <jasowang at redhat.com> 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]))Yes. This looks better and we don't even need device specific configuration method.> > 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.Can we give a device specific meaning for this? For virtio-net, we want to expose the coalescing settings through ethtool (tx-frames). And it was usually used with a timer, so probably another field after vring_used_delay() for this timer interval to trigger the interrupt if no new used buffers come after this interval.> > > My feeling is that this should be a v1.0-only feature though > (eg. feature bit 33).Yes it should.> > Cheers, > Rusty. > >> Cc: Rusty Russell <rusty at rustcorp.com.au> >> Cc: Michael S. Tsirkin <mst at redhat.com> >> Signed-off-by: Jason Wang <jasowang at redhat.com> >> --- >> drivers/net/virtio_net.c | 67 >> +++++++++++++++++++++++++++++++++++++++++ >> include/uapi/linux/virtio_net.h | 12 ++++++++ >> 2 files changed, 79 insertions(+) >> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index cc5f5de..2b958fb 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -145,6 +145,11 @@ struct virtnet_info { >> >> /* Budget for polling tx completion */ >> u32 tx_work_limit; >> + >> + __u32 rx_coalesce_usecs; >> + __u32 rx_max_coalesced_frames; >> + __u32 tx_coalesce_usecs; >> + __u32 tx_max_coalesced_frames; >> }; >> >> struct padded_vnet_hdr { >> @@ -1404,12 +1409,73 @@ static void virtnet_get_channels(struct >> net_device *dev, >> channels->other_count = 0; >> } >> >> +static int virtnet_set_coalesce(struct net_device *dev, >> + struct ethtool_coalesce *ec) >> +{ >> + struct virtnet_info *vi = netdev_priv(dev); >> + struct scatterlist sg; >> + struct virtio_net_ctrl_coalesce c; >> + >> + if (!vi->has_cvq || >> + !virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_COALESCE)) >> + return -EOPNOTSUPP; >> + if (vi->rx_coalesce_usecs != ec->rx_coalesce_usecs || >> + vi->rx_max_coalesced_frames != ec->rx_max_coalesced_frames) { >> + c.coalesce_usecs = ec->rx_coalesce_usecs; >> + c.max_coalesced_frames = ec->rx_max_coalesced_frames; >> + sg_init_one(&sg, &c, sizeof(c)); >> + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_COALESCE, >> + VIRTIO_NET_CTRL_COALESCE_RX_SET, >> + &sg)) { >> + dev_warn(&dev->dev, "Fail to set rx coalescing\n"); >> + return -EINVAL; >> + } >> + vi->rx_coalesce_usecs = ec->rx_coalesce_usecs; >> + vi->rx_max_coalesced_frames = ec->rx_max_coalesced_frames; >> + } >> + >> + if (vi->tx_coalesce_usecs != ec->tx_coalesce_usecs || >> + vi->tx_max_coalesced_frames != ec->tx_max_coalesced_frames) { >> + c.coalesce_usecs = ec->tx_coalesce_usecs; >> + c.max_coalesced_frames = ec->tx_max_coalesced_frames; >> + sg_init_one(&sg, &c, sizeof(c)); >> + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_COALESCE, >> + VIRTIO_NET_CTRL_COALESCE_TX_SET, >> + &sg)) { >> + dev_warn(&dev->dev, "Fail to set tx coalescing\n"); >> + return -EINVAL; >> + } >> + vi->tx_coalesce_usecs = ec->tx_coalesce_usecs; >> + vi->tx_max_coalesced_frames = ec->tx_max_coalesced_frames; >> + } >> + >> + vi->tx_work_limit = ec->tx_max_coalesced_frames_irq; >> + >> + return 0; >> +} >> + >> +static int virtnet_get_coalesce(struct net_device *dev, >> + struct ethtool_coalesce *ec) >> +{ >> + struct virtnet_info *vi = netdev_priv(dev); >> + >> + ec->rx_coalesce_usecs = vi->rx_coalesce_usecs; >> + ec->rx_max_coalesced_frames = vi->rx_max_coalesced_frames; >> + ec->tx_coalesce_usecs = vi->tx_coalesce_usecs; >> + ec->tx_max_coalesced_frames = vi->tx_max_coalesced_frames; >> + ec->tx_max_coalesced_frames_irq = vi->tx_work_limit; >> + >> + return 0; >> +} >> + >> static const struct ethtool_ops virtnet_ethtool_ops = { >> .get_drvinfo = virtnet_get_drvinfo, >> .get_link = ethtool_op_get_link, >> .get_ringparam = virtnet_get_ringparam, >> .set_channels = virtnet_set_channels, >> .get_channels = virtnet_get_channels, >> + .set_coalesce = virtnet_set_coalesce, >> + .get_coalesce = virtnet_get_coalesce, >> }; >> >> #define MIN_MTU 68 >> @@ -2048,6 +2114,7 @@ static unsigned int features[] = { >> VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, >> VIRTIO_NET_F_CTRL_MAC_ADDR, >> VIRTIO_F_ANY_LAYOUT, >> + VIRTIO_NET_F_CTRL_COALESCE, >> }; >> >> static struct virtio_driver virtio_net_driver = { >> diff --git a/include/uapi/linux/virtio_net.h >> b/include/uapi/linux/virtio_net.h >> index b5f1677..332009d 100644 >> --- a/include/uapi/linux/virtio_net.h >> +++ b/include/uapi/linux/virtio_net.h >> @@ -34,6 +34,7 @@ >> /* The feature bitmap for virtio net */ >> #define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */ >> #define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial >> csum */ >> +#define VIRTIO_NET_F_CTRL_COALESCE 3 /* Set coalescing */ >> #define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */ >> #define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */ >> #define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */ >> @@ -202,4 +203,15 @@ struct virtio_net_ctrl_mq { >> #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN 1 >> #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX 0x8000 >> >> +struct virtio_net_ctrl_coalesce { >> + __u32 coalesce_usecs; >> + __u32 max_coalesced_frames; >> +}; >> + >> +#define VIRTIO_NET_CTRL_COALESCE 6 >> + #define VIRTIO_NET_CTRL_COALESCE_TX_SET 0 >> + #define VIRTIO_NET_CTRL_COALESCE_TX_GET 1 >> + #define VIRTIO_NET_CTRL_COALESCE_RX_SET 2 >> + #define VIRTIO_NET_CTRL_COALESCE_RX_GET 3 >> + >> #endif /* _LINUX_VIRTIO_NET_H */ >> -- >> 1.8.3.1 > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
Michael S. Tsirkin
2015-Feb-10 10:25 UTC
[PATCH RFC v5 net-next 4/6] virtio-net: add basic interrupt coalescing support
On Tue, Feb 10, 2015 at 06:59:30AM +0008, Jason Wang wrote:> > > On Tue, Feb 10, 2015 at 9:32 AM, Rusty Russell <rusty at rustcorp.com.au> > wrote: > >Jason Wang <jasowang at redhat.com> 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])) > > Yes. This looks better and we don't even need device specific configuration > method. > > > > >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. > > Can we give a device specific meaning for this? For virtio-net, we want to > expose the coalescing settings through ethtool (tx-frames). And it was > usually used with a timer, so probably another field after > vring_used_delay() for this timer interval to trigger the interrupt if no > new used buffers come after this interval.I think what Rusty has in mind is precisely sticking the delay in vring_used_delay.> > > > > >My feeling is that this should be a v1.0-only feature though > >(eg. feature bit 33). > > Yes it should. > > > > >Cheers, > >Rusty. > > > >> Cc: Rusty Russell <rusty at rustcorp.com.au> > >> Cc: Michael S. Tsirkin <mst at redhat.com> > >> Signed-off-by: Jason Wang <jasowang at redhat.com> > >> --- > >> drivers/net/virtio_net.c | 67 > >>+++++++++++++++++++++++++++++++++++++++++ > >> include/uapi/linux/virtio_net.h | 12 ++++++++ > >> 2 files changed, 79 insertions(+) > >> > >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > >> index cc5f5de..2b958fb 100644 > >> --- a/drivers/net/virtio_net.c > >> +++ b/drivers/net/virtio_net.c > >> @@ -145,6 +145,11 @@ struct virtnet_info { > >> /* Budget for polling tx completion */ > >> u32 tx_work_limit; > >> + > >> + __u32 rx_coalesce_usecs; > >> + __u32 rx_max_coalesced_frames; > >> + __u32 tx_coalesce_usecs; > >> + __u32 tx_max_coalesced_frames; > >> }; > >> struct padded_vnet_hdr { > >> @@ -1404,12 +1409,73 @@ static void virtnet_get_channels(struct > >>net_device *dev, > >> channels->other_count = 0; > >> } > >> +static int virtnet_set_coalesce(struct net_device *dev, > >> + struct ethtool_coalesce *ec) > >> +{ > >> + struct virtnet_info *vi = netdev_priv(dev); > >> + struct scatterlist sg; > >> + struct virtio_net_ctrl_coalesce c; > >> + > >> + if (!vi->has_cvq || > >> + !virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_COALESCE)) > >> + return -EOPNOTSUPP; > >> + if (vi->rx_coalesce_usecs != ec->rx_coalesce_usecs || > >> + vi->rx_max_coalesced_frames != ec->rx_max_coalesced_frames) { > >> + c.coalesce_usecs = ec->rx_coalesce_usecs; > >> + c.max_coalesced_frames = ec->rx_max_coalesced_frames; > >> + sg_init_one(&sg, &c, sizeof(c)); > >> + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_COALESCE, > >> + VIRTIO_NET_CTRL_COALESCE_RX_SET, > >> + &sg)) { > >> + dev_warn(&dev->dev, "Fail to set rx coalescing\n"); > >> + return -EINVAL; > >> + } > >> + vi->rx_coalesce_usecs = ec->rx_coalesce_usecs; > >> + vi->rx_max_coalesced_frames = ec->rx_max_coalesced_frames; > >> + } > >> + > >> + if (vi->tx_coalesce_usecs != ec->tx_coalesce_usecs || > >> + vi->tx_max_coalesced_frames != ec->tx_max_coalesced_frames) { > >> + c.coalesce_usecs = ec->tx_coalesce_usecs; > >> + c.max_coalesced_frames = ec->tx_max_coalesced_frames; > >> + sg_init_one(&sg, &c, sizeof(c)); > >> + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_COALESCE, > >> + VIRTIO_NET_CTRL_COALESCE_TX_SET, > >> + &sg)) { > >> + dev_warn(&dev->dev, "Fail to set tx coalescing\n"); > >> + return -EINVAL; > >> + } > >> + vi->tx_coalesce_usecs = ec->tx_coalesce_usecs; > >> + vi->tx_max_coalesced_frames = ec->tx_max_coalesced_frames; > >> + } > >> + > >> + vi->tx_work_limit = ec->tx_max_coalesced_frames_irq; > >> + > >> + return 0; > >> +} > >> + > >> +static int virtnet_get_coalesce(struct net_device *dev, > >> + struct ethtool_coalesce *ec) > >> +{ > >> + struct virtnet_info *vi = netdev_priv(dev); > >> + > >> + ec->rx_coalesce_usecs = vi->rx_coalesce_usecs; > >> + ec->rx_max_coalesced_frames = vi->rx_max_coalesced_frames; > >> + ec->tx_coalesce_usecs = vi->tx_coalesce_usecs; > >> + ec->tx_max_coalesced_frames = vi->tx_max_coalesced_frames; > >> + ec->tx_max_coalesced_frames_irq = vi->tx_work_limit; > >> + > >> + return 0; > >> +} > >> + > >> static const struct ethtool_ops virtnet_ethtool_ops = { > >> .get_drvinfo = virtnet_get_drvinfo, > >> .get_link = ethtool_op_get_link, > >> .get_ringparam = virtnet_get_ringparam, > >> .set_channels = virtnet_set_channels, > >> .get_channels = virtnet_get_channels, > >> + .set_coalesce = virtnet_set_coalesce, > >> + .get_coalesce = virtnet_get_coalesce, > >> }; > >> #define MIN_MTU 68 > >> @@ -2048,6 +2114,7 @@ static unsigned int features[] = { > >> VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, > >> VIRTIO_NET_F_CTRL_MAC_ADDR, > >> VIRTIO_F_ANY_LAYOUT, > >> + VIRTIO_NET_F_CTRL_COALESCE, > >> }; > >> static struct virtio_driver virtio_net_driver = { > >> diff --git a/include/uapi/linux/virtio_net.h > >>b/include/uapi/linux/virtio_net.h > >> index b5f1677..332009d 100644 > >> --- a/include/uapi/linux/virtio_net.h > >> +++ b/include/uapi/linux/virtio_net.h > >> @@ -34,6 +34,7 @@ > >> /* The feature bitmap for virtio net */ > >> #define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */ > >> #define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial > >>csum */ > >> +#define VIRTIO_NET_F_CTRL_COALESCE 3 /* Set coalescing */ > >> #define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */ > >> #define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */ > >> #define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */ > >> @@ -202,4 +203,15 @@ struct virtio_net_ctrl_mq { > >> #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN 1 > >> #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX 0x8000 > >> +struct virtio_net_ctrl_coalesce { > >> + __u32 coalesce_usecs; > >> + __u32 max_coalesced_frames; > >> +}; > >> + > >> +#define VIRTIO_NET_CTRL_COALESCE 6 > >> + #define VIRTIO_NET_CTRL_COALESCE_TX_SET 0 > >> + #define VIRTIO_NET_CTRL_COALESCE_TX_GET 1 > >> + #define VIRTIO_NET_CTRL_COALESCE_RX_SET 2 > >> + #define VIRTIO_NET_CTRL_COALESCE_RX_GET 3 > >> + > >> #endif /* _LINUX_VIRTIO_NET_H */ > >> -- 1.8.3.1 > >-- > >To unsubscribe from this list: send the line "unsubscribe netdev" in > >the body of a message to majordomo at vger.kernel.org > >More majordomo info at http://vger.kernel.org/majordomo-info.html
Michael S. Tsirkin
2015-Feb-10 10:40 UTC
[PATCH RFC v5 net-next 4/6] virtio-net: add basic interrupt coalescing support
On Tue, Feb 10, 2015 at 12:02:37PM +1030, Rusty Russell wrote:> Jason Wang <jasowang at redhat.com> 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?> My feeling is that this should be a v1.0-only feature though > (eg. feature bit 33). > > Cheers, > Rusty.Yes, e.g. we can't extend config space for legacy virtio pci.> > Cc: Rusty Russell <rusty at rustcorp.com.au> > > Cc: Michael S. Tsirkin <mst at redhat.com> > > Signed-off-by: Jason Wang <jasowang at redhat.com> > > --- > > drivers/net/virtio_net.c | 67 +++++++++++++++++++++++++++++++++++++++++ > > include/uapi/linux/virtio_net.h | 12 ++++++++ > > 2 files changed, 79 insertions(+) > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index cc5f5de..2b958fb 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -145,6 +145,11 @@ struct virtnet_info { > > > > /* Budget for polling tx completion */ > > u32 tx_work_limit; > > + > > + __u32 rx_coalesce_usecs; > > + __u32 rx_max_coalesced_frames; > > + __u32 tx_coalesce_usecs; > > + __u32 tx_max_coalesced_frames; > > }; > > > > struct padded_vnet_hdr { > > @@ -1404,12 +1409,73 @@ static void virtnet_get_channels(struct net_device *dev, > > channels->other_count = 0; > > } > > > > +static int virtnet_set_coalesce(struct net_device *dev, > > + struct ethtool_coalesce *ec) > > +{ > > + struct virtnet_info *vi = netdev_priv(dev); > > + struct scatterlist sg; > > + struct virtio_net_ctrl_coalesce c; > > + > > + if (!vi->has_cvq || > > + !virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_COALESCE)) > > + return -EOPNOTSUPP; > > + if (vi->rx_coalesce_usecs != ec->rx_coalesce_usecs || > > + vi->rx_max_coalesced_frames != ec->rx_max_coalesced_frames) { > > + c.coalesce_usecs = ec->rx_coalesce_usecs; > > + c.max_coalesced_frames = ec->rx_max_coalesced_frames; > > + sg_init_one(&sg, &c, sizeof(c)); > > + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_COALESCE, > > + VIRTIO_NET_CTRL_COALESCE_RX_SET, > > + &sg)) { > > + dev_warn(&dev->dev, "Fail to set rx coalescing\n"); > > + return -EINVAL; > > + } > > + vi->rx_coalesce_usecs = ec->rx_coalesce_usecs; > > + vi->rx_max_coalesced_frames = ec->rx_max_coalesced_frames; > > + } > > + > > + if (vi->tx_coalesce_usecs != ec->tx_coalesce_usecs || > > + vi->tx_max_coalesced_frames != ec->tx_max_coalesced_frames) { > > + c.coalesce_usecs = ec->tx_coalesce_usecs; > > + c.max_coalesced_frames = ec->tx_max_coalesced_frames; > > + sg_init_one(&sg, &c, sizeof(c)); > > + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_COALESCE, > > + VIRTIO_NET_CTRL_COALESCE_TX_SET, > > + &sg)) { > > + dev_warn(&dev->dev, "Fail to set tx coalescing\n"); > > + return -EINVAL; > > + } > > + vi->tx_coalesce_usecs = ec->tx_coalesce_usecs; > > + vi->tx_max_coalesced_frames = ec->tx_max_coalesced_frames; > > + } > > + > > + vi->tx_work_limit = ec->tx_max_coalesced_frames_irq; > > + > > + return 0; > > +} > > + > > +static int virtnet_get_coalesce(struct net_device *dev, > > + struct ethtool_coalesce *ec) > > +{ > > + struct virtnet_info *vi = netdev_priv(dev); > > + > > + ec->rx_coalesce_usecs = vi->rx_coalesce_usecs; > > + ec->rx_max_coalesced_frames = vi->rx_max_coalesced_frames; > > + ec->tx_coalesce_usecs = vi->tx_coalesce_usecs; > > + ec->tx_max_coalesced_frames = vi->tx_max_coalesced_frames; > > + ec->tx_max_coalesced_frames_irq = vi->tx_work_limit; > > + > > + return 0; > > +} > > + > > static const struct ethtool_ops virtnet_ethtool_ops = { > > .get_drvinfo = virtnet_get_drvinfo, > > .get_link = ethtool_op_get_link, > > .get_ringparam = virtnet_get_ringparam, > > .set_channels = virtnet_set_channels, > > .get_channels = virtnet_get_channels, > > + .set_coalesce = virtnet_set_coalesce, > > + .get_coalesce = virtnet_get_coalesce, > > }; > > > > #define MIN_MTU 68 > > @@ -2048,6 +2114,7 @@ static unsigned int features[] = { > > VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, > > VIRTIO_NET_F_CTRL_MAC_ADDR, > > VIRTIO_F_ANY_LAYOUT, > > + VIRTIO_NET_F_CTRL_COALESCE, > > }; > > > > static struct virtio_driver virtio_net_driver = { > > diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h > > index b5f1677..332009d 100644 > > --- a/include/uapi/linux/virtio_net.h > > +++ b/include/uapi/linux/virtio_net.h > > @@ -34,6 +34,7 @@ > > /* The feature bitmap for virtio net */ > > #define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */ > > #define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */ > > +#define VIRTIO_NET_F_CTRL_COALESCE 3 /* Set coalescing */ > > #define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */ > > #define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */ > > #define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */ > > @@ -202,4 +203,15 @@ struct virtio_net_ctrl_mq { > > #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN 1 > > #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX 0x8000 > > > > +struct virtio_net_ctrl_coalesce { > > + __u32 coalesce_usecs; > > + __u32 max_coalesced_frames; > > +}; > > + > > +#define VIRTIO_NET_CTRL_COALESCE 6 > > + #define VIRTIO_NET_CTRL_COALESCE_TX_SET 0 > > + #define VIRTIO_NET_CTRL_COALESCE_TX_GET 1 > > + #define VIRTIO_NET_CTRL_COALESCE_RX_SET 2 > > + #define VIRTIO_NET_CTRL_COALESCE_RX_GET 3 > > + > > #endif /* _LINUX_VIRTIO_NET_H */ > > -- > > 1.8.3.1
Rusty Russell
2015-Feb-13 02:52 UTC
[PATCH RFC v5 net-next 4/6] virtio-net: add basic interrupt coalescing support
"Michael S. Tsirkin" <mst at redhat.com> writes:> On Tue, Feb 10, 2015 at 12:02:37PM +1030, Rusty Russell wrote: >> Jason Wang <jasowang at redhat.com> 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.
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