On Tue, 17 Oct 2023 14:43:33 +0800, Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote: > On Tue, 17 Oct 2023 14:26:01 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote: > > On Tue, Oct 17, 2023 at 2:17 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote: > > > > > > On Tue, 17 Oct 2023 13:27:47 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > > On Tue, Oct 17, 2023 at 11:28 AM Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > > > > > > > > On Tue, Oct 17, 2023 at 11:26 AM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote: > > > > > > > > > > > > On Tue, 17 Oct 2023 11:20:41 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > > > > > On Tue, Oct 17, 2023 at 11:11 AM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > On Tue, 17 Oct 2023 10:53:44 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > > > > > > > On Mon, Oct 16, 2023 at 8:00 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > > > > ## AF_XDP > > > > > > > > > > > > > > > > > > > > XDP socket(AF_XDP) is an excellent bypass kernel network framework. The zero > > > > > > > > > > copy feature of xsk (XDP socket) needs to be supported by the driver. The > > > > > > > > > > performance of zero copy is very good. mlx5 and intel ixgbe already support > > > > > > > > > > this feature, This patch set allows virtio-net to support xsk's zerocopy xmit > > > > > > > > > > feature. > > > > > > > > > > > > > > > > > > > > At present, we have completed some preparation: > > > > > > > > > > > > > > > > > > > > 1. vq-reset (virtio spec and kernel code) > > > > > > > > > > 2. virtio-core premapped dma > > > > > > > > > > 3. virtio-net xdp refactor > > > > > > > > > > > > > > > > > > > > So it is time for Virtio-Net to complete the support for the XDP Socket > > > > > > > > > > Zerocopy. > > > > > > > > > > > > > > > > > > > > Virtio-net can not increase the queue num at will, so xsk shares the queue with > > > > > > > > > > kernel. > > > > > > > > > > > > > > > > > > > > On the other hand, Virtio-Net does not support generate interrupt from driver > > > > > > > > > > manually, so when we wakeup tx xmit, we used some tips. If the CPU run by TX > > > > > > > > > > NAPI last time is other CPUs, use IPI to wake up NAPI on the remote CPU. If it > > > > > > > > > > is also the local CPU, then we wake up napi directly. > > > > > > > > > > > > > > > > > > > > This patch set includes some refactor to the virtio-net to let that to support > > > > > > > > > > AF_XDP. > > > > > > > > > > > > > > > > > > > > ## performance > > > > > > > > > > > > > > > > > > > > ENV: Qemu with vhost-user(polling mode). > > > > > > > > > > > > > > > > > > > > Sockperf: https://github.com/Mellanox/sockperf > > > > > > > > > > I use this tool to send udp packet by kernel syscall. > > > > > > > > > > > > > > > > > > > > xmit command: sockperf tp -i 10.0.3.1 -t 1000 > > > > > > > > > > > > > > > > > > > > I write a tool that sends udp packets or recvs udp packets by AF_XDP. > > > > > > > > > > > > > > > > > > > > | Guest APP CPU |Guest Softirq CPU | UDP PPS > > > > > > > > > > ------------------|---------------|------------------|------------ > > > > > > > > > > xmit by syscall | 100% | | 676,915 > > > > > > > > > > xmit by xsk | 59.1% | 100% | 5,447,168 > > > > > > > > > > recv by syscall | 60% | 100% | 932,288 > > > > > > > > > > recv by xsk | 35.7% | 100% | 3,343,168 > > > > > > > > > > > > > > > > > > Any chance we can get a testpmd result (which I guess should be better > > > > > > > > > than PPS above)? > > > > > > > > > > > > > > > > Do you mean testpmd + DPDK + AF_XDP? > > > > > > > > > > > > > > Yes. > > > > > > > > > > > > > > > > > > > > > > > Yes. This is probably better because my tool does more work. That is not a > > > > > > > > complete testing tool used by our business. > > > > > > > > > > > > > > Probably, but it would be appealing for others. Especially considering > > > > > > > DPDK supports AF_XDP PMD now. > > > > > > > > > > > > OK. > > > > > > > > > > > > Let me try. > > > > > > > > > > > > But could you start to review firstly? > > > > > > > > > > Yes, it's in my todo list. > > > > > > > > Speaking too fast, I think if it doesn't take too long time, I would > > > > wait for the result first as netdim series. One reason is that I > > > > remember claims to be only 10% to 20% loss comparing to wire speed, so > > > > I'd expect it should be much faster. I vaguely remember, even a vhost > > > > can gives us more than 3M PPS if we disable SMAP, so the numbers here > > > > are not as impressive as expected. > > > > > > > > > What is SMAP? Cloud you give me more info? > > > > Supervisor Mode Access Prevention > > > > Vhost suffers from this. > > > > > > > > So if we think the 3M as the wire speed, you expect the result > > > can reach 2.8M pps/core, right? > > > > It's AF_XDP that claims to be 80% if my memory is correct. So a > > correct AF_XDP implementation should not sit behind this too much. > > > > > Now the recv result is 2.5M(2463646) pps/core. > > > Do you think there is a huge gap? > > > > You never describe your testing environment in details. For example, > > is this a virtual environment? What's the CPU model and frequency etc. > > > > Because I never see a NIC whose wire speed is 3M. > > > > > > > > My tool makes udp packet and lookup route, so it take more much cpu. > > > > That's why I suggest you to test raw PPS. > > OK. Let's align some info. > > 1. My test env is vhost-user. Qemu + vhost-user(polling mode). > I do not use the DPDK, because that there is some trouble for me. > I use the VAPP (https://github.com/fengidri/vapp) as the vhost-user device. > That has two threads all are busy mode for tx and rx. > tx thread consumes the tx ring and drop the packet. > rx thread put the packet to the rx ring. > > 2. My Host CPU: Intel(R) Xeon(R) Platinum 8163 CPU @ 2.50GHz > > 3. From this http://fast.dpdk.org/doc/perf/DPDK_23_03_Intel_virtio_performance_report.pdf > I think we can align that the vhost max speed is 8.5 MPPS. > Is that ok? > And the expected AF_XDP pps is about 6 MPPS. > > 4. About the raw PPS, I agree that. I will test with testpmd. > ## testpmd command ./build/app/dpdk-testpmd -l 1-2 --no-pci --main-lcore=2 \ --vdev net_af_xdp0,iface=ens5,queue_count=1,busy_budget=0 \ --log-level=pmd.net.af_xdp:8 \ -- -i -a --nb-cores=1 --rxq=1 --txq=1 --forward-mode=macswap ## work without the follow patch[0] testpmd> show port stats all ######################## NIC statistics for port 0 ######################## RX-packets: 3615824336 RX-missed: 0 RX-bytes: 202486162816 RX-errors: 0 RX-nombuf: 0 TX-packets: 3615795592 TX-errors: 20738 TX-bytes: 202484553152 Throughput (since last show) Rx-pps: 3790446 Rx-bps: 1698120056 Tx-pps: 3790446 Tx-bps: 1698120056 ############################################################################ ## work with the follow patch[0] testpmd> show port stats all ######################## NIC statistics for port 0 ######################## RX-packets: 68152727 RX-missed: 0 RX-bytes: 3816552712 RX-errors: 0 RX-nombuf: 0 TX-packets: 68114967 TX-errors: 33216 TX-bytes: 3814438152 Throughput (since last show) Rx-pps: 6333196 Rx-bps: 2837272088 Tx-pps: 6333227 Tx-bps: 2837285936 ############################################################################ I search the dpdk code that the dpdk virtio driver has the similar code. virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts) { [...] for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) { [...] /* Enqueue Packet buffers */ virtqueue_enqueue_xmit(txvq, txm, slots, use_indirect, can_push, 0); } [...] if (likely(nb_tx)) { --> vq_update_avail_idx(vq); if (unlikely(virtqueue_kick_prepare(vq))) { virtqueue_notify(vq); PMD_TX_LOG(DEBUG, "Notified backend after xmit"); } } } ## patch[0] diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 51d8f3299c10..cfe556b5d88f 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -687,12 +687,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, avail = vq->split.avail_idx_shadow & (vq->split.vring.num - 1); vq->split.vring.avail->ring[avail] = cpu_to_virtio16(_vq->vdev, head); - /* Descriptors and available array need to be set before we expose the - * new available array entries. */ - virtio_wmb(vq->weak_barriers); vq->split.avail_idx_shadow++; - vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev, - vq->split.avail_idx_shadow); vq->num_added++; pr_debug("Added buffer head %i to %p\n", head, vq); @@ -700,8 +695,12 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, /* This is very unlikely, but theoretically possible. Kick * just in case. */ - if (unlikely(vq->num_added == (1 << 16) - 1)) + if (unlikely(vq->num_added == (1 << 16) - 1)) { + virtio_wmb(vq->weak_barriers); + vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev, + vq->split.avail_idx_shadow); virtqueue_kick(_vq); + } return 0; @@ -742,6 +741,9 @@ static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) * event. */ virtio_mb(vq->weak_barriers); + vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev, + vq->split.avail_idx_shadow); + old = vq->split.avail_idx_shadow - vq->num_added; new = vq->split.avail_idx_shadow; vq->num_added = 0; --------------- Thanks. > > Thanks. > > > > > > Thanks > > > > > > > > I am confused. > > > > > > > > > What is SMAP? Could you give me more information? > > > > > > So if we use 3M as the wire speed, you would expect the result to be 2.8M > > > pps/core, right? > > > > > > Now the recv result is 2.5M (2463646 = 3,343,168/1.357) pps/core. Do you think > > > the difference is big? > > > > > > My tool makes udp packets and looks up routes, so it requires more CPU. > > > > > > I'm confused. Is there something I misunderstood? > > > > > > Thanks. > > > > > > > > > > > Thanks > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > What I noticed is that the hotspot is the driver writing virtio desc. Because > > > > > > > > the device is in busy mode. So there is race between driver and device. > > > > > > > > So I modified the virtio core and lazily updated avail idx. Then pps can reach > > > > > > > > 10,000,000. > > > > > > > > > > > > > > Care to post a draft for this? > > > > > > > > > > > > YES, I is thinking for this. > > > > > > But maybe that is just work for split. The packed mode has some troubles. > > > > > > > > > > Ok. > > > > > > > > > > Thanks > > > > > > > > > > > > > > > > > Thanks. > > > > > > > > > > > > > > > > > > > > Thanks > > > > > > > > > > > > > > > > > > > > > > > Thanks. > > > > > > > > > > > > > > > > > > > > > > > > > > Thanks > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ## maintain > > > > > > > > > > > > > > > > > > > > I am currently a reviewer for virtio-net. I commit to maintain AF_XDP support in > > > > > > > > > > virtio-net. > > > > > > > > > > > > > > > > > > > > Please review. > > > > > > > > > > > > > > > > > > > > Thanks. > > > > > > > > > > > > > > > > > > > > v1: > > > > > > > > > > 1. remove two virtio commits. Push this patchset to net-next > > > > > > > > > > 2. squash "virtio_net: virtnet_poll_tx support rescheduled" to xsk: support tx > > > > > > > > > > 3. fix some warnings > > > > > > > > > > > > > > > > > > > > Xuan Zhuo (19): > > > > > > > > > > virtio_net: rename free_old_xmit_skbs to free_old_xmit > > > > > > > > > > virtio_net: unify the code for recycling the xmit ptr > > > > > > > > > > virtio_net: independent directory > > > > > > > > > > virtio_net: move to virtio_net.h > > > > > > > > > > virtio_net: add prefix virtnet to all struct/api inside virtio_net.h > > > > > > > > > > virtio_net: separate virtnet_rx_resize() > > > > > > > > > > virtio_net: separate virtnet_tx_resize() > > > > > > > > > > virtio_net: sq support premapped mode > > > > > > > > > > virtio_net: xsk: bind/unbind xsk > > > > > > > > > > virtio_net: xsk: prevent disable tx napi > > > > > > > > > > virtio_net: xsk: tx: support tx > > > > > > > > > > virtio_net: xsk: tx: support wakeup > > > > > > > > > > virtio_net: xsk: tx: virtnet_free_old_xmit() distinguishes xsk buffer > > > > > > > > > > virtio_net: xsk: tx: virtnet_sq_free_unused_buf() check xsk buffer > > > > > > > > > > virtio_net: xsk: rx: introduce add_recvbuf_xsk() > > > > > > > > > > virtio_net: xsk: rx: introduce receive_xsk() to recv xsk buffer > > > > > > > > > > virtio_net: xsk: rx: virtnet_rq_free_unused_buf() check xsk buffer > > > > > > > > > > virtio_net: update tx timeout record > > > > > > > > > > virtio_net: xdp_features add NETDEV_XDP_ACT_XSK_ZEROCOPY > > > > > > > > > > > > > > > > > > > > MAINTAINERS | 2 +- > > > > > > > > > > drivers/net/Kconfig | 8 +- > > > > > > > > > > drivers/net/Makefile | 2 +- > > > > > > > > > > drivers/net/virtio/Kconfig | 13 + > > > > > > > > > > drivers/net/virtio/Makefile | 8 + > > > > > > > > > > drivers/net/{virtio_net.c => virtio/main.c} | 652 +++++++++----------- > > > > > > > > > > drivers/net/virtio/virtio_net.h | 359 +++++++++++ > > > > > > > > > > drivers/net/virtio/xsk.c | 545 ++++++++++++++++ > > > > > > > > > > drivers/net/virtio/xsk.h | 32 + > > > > > > > > > > 9 files changed, 1247 insertions(+), 374 deletions(-) > > > > > > > > > > create mode 100644 drivers/net/virtio/Kconfig > > > > > > > > > > create mode 100644 drivers/net/virtio/Makefile > > > > > > > > > > rename drivers/net/{virtio_net.c => virtio/main.c} (91%) > > > > > > > > > > create mode 100644 drivers/net/virtio/virtio_net.h > > > > > > > > > > create mode 100644 drivers/net/virtio/xsk.c > > > > > > > > > > create mode 100644 drivers/net/virtio/xsk.h > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > 2.32.0.3.g01195cf9f > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
