Tue, Jun 18, 2024 at 02:53:42AM CEST, jasowang@xxxxxxxxxx wrote:
>On Mon, Jun 17, 2024 at 5:18 PM Jiri Pirko <jiri@xxxxxxxxxxx> wrote:
>>
>> Mon, Jun 17, 2024 at 04:34:26AM CEST, jasowang@xxxxxxxxxx wrote:
>> >On Thu, Jun 13, 2024 at 1:09 AM Jiri Pirko <jiri@xxxxxxxxxxx> wrote:
>> >>
>> >> From: Jiri Pirko <jiri@xxxxxxxxxx>
>> >>
>> >> Add support for Byte Queue Limits (BQL).
>> >>
>> >> Tested on qemu emulated virtio_net device with 1, 2 and 4 queues.
>> >> Tested with fq_codel and pfifo_fast. Super netperf with 50 threads is
>> >> running in background. Netperf TCP_RR results:
>> >>
>> >> NOBQL FQC 1q: 159.56 159.33 158.50 154.31 agv: 157.925
>> >> NOBQL FQC 2q: 184.64 184.96 174.73 174.15 agv: 179.62
>> >> NOBQL FQC 4q: 994.46 441.96 416.50 499.56 agv: 588.12
>> >> NOBQL PFF 1q: 148.68 148.92 145.95 149.48 agv: 148.2575
>> >> NOBQL PFF 2q: 171.86 171.20 170.42 169.42 agv: 170.725
>> >> NOBQL PFF 4q: 1505.23 1137.23 2488.70 3507.99 agv: 2159.7875
>> >> BQL FQC 1q: 1332.80 1297.97 1351.41 1147.57 agv: 1282.4375
>> >> BQL FQC 2q: 768.30 817.72 864.43 974.40 agv: 856.2125
>> >> BQL FQC 4q: 945.66 942.68 878.51 822.82 agv: 897.4175
>> >> BQL PFF 1q: 149.69 151.49 149.40 147.47 agv: 149.5125
>> >> BQL PFF 2q: 2059.32 798.74 1844.12 381.80 agv: 1270.995
>> >> BQL PFF 4q: 1871.98 4420.02 4916.59 13268.16 agv: 6119.1875
>> >>
>> >> Signed-off-by: Jiri Pirko <jiri@xxxxxxxxxx>
>> >> ---
>> >> v1->v2:
>> >> - moved netdev_tx_completed_queue() call into __free_old_xmit(),
>> >> propagate use_napi flag to __free_old_xmit() and only call
>> >> netdev_tx_completed_queue() in case it is true
>> >> - added forgotten call to netdev_tx_reset_queue()
>> >> - fixed stats for xdp packets
>> >> - fixed bql accounting when __free_old_xmit() is called from xdp path
>> >> - handle the !use_napi case in start_xmit() kick section
>> >> ---
>> >> drivers/net/virtio_net.c | 50 +++++++++++++++++++++++++---------------
>> >> 1 file changed, 32 insertions(+), 18 deletions(-)
>> >>
>> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> >> index 61a57d134544..5863c663ccab 100644
>> >> --- a/drivers/net/virtio_net.c
>> >> +++ b/drivers/net/virtio_net.c
>> >> @@ -84,7 +84,9 @@ struct virtnet_stat_desc {
>> >>
>> >> struct virtnet_sq_free_stats {
>> >> u64 packets;
>> >> + u64 xdp_packets;
>> >> u64 bytes;
>> >> + u64 xdp_bytes;
>> >> };
>> >>
>> >> struct virtnet_sq_stats {
>> >> @@ -506,29 +508,33 @@ static struct xdp_frame *ptr_to_xdp(void *ptr)
>> >> return (struct xdp_frame *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG);
>> >> }
>> >>
>> >> -static void __free_old_xmit(struct send_queue *sq, bool in_napi,
>> >> +static void __free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
>> >> + bool in_napi, bool use_napi,
>> >> struct virtnet_sq_free_stats *stats)
>> >> {
>> >> unsigned int len;
>> >> void *ptr;
>> >>
>> >> while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
>> >> - ++stats->packets;
>> >> -
>> >> if (!is_xdp_frame(ptr)) {
>> >> struct sk_buff *skb = ptr;
>> >>
>> >> pr_debug("Sent skb %p\n", skb);
>> >>
>> >> + stats->packets++;
>> >> stats->bytes += skb->len;
>> >> napi_consume_skb(skb, in_napi);
>> >> } else {
>> >> struct xdp_frame *frame = ptr_to_xdp(ptr);
>> >>
>> >> - stats->bytes += xdp_get_frame_len(frame);
>> >> + stats->xdp_packets++;
>> >> + stats->xdp_bytes += xdp_get_frame_len(frame);
>> >> xdp_return_frame(frame);
>> >> }
>> >> }
>> >> + if (use_napi)
>> >> + netdev_tx_completed_queue(txq, stats->packets, stats->bytes);
>> >> +
>> >> }
>> >
>> >I wonder if this works correctly, for example NAPI could be enabled
>> >after queued but before sent. So __netdev_tx_sent_queue() is not
>> >called before.
>>
>> How is that possible? Napi weight can't change when link is up. Or am I
>> missing something?
>
>Something like this:
>
>1) packet were queued
>2) if down
>3) enable NAPI
>4) if up
>5) packet were sent
Gotcha, will try to fix. Thanks!
>
>?
>
>Thanks
>
>>
>> >
>> >Thanks
>> >
>>
>
