On Mon, 2018-09-03 at 10:36 +0100, Jose Abreu wrote:
> Hi Jerome,
>
> On 03-09-2018 09:56, Jerome Brunet wrote:
> > On Thu, 2018-08-30 at 11:37 +0100, Jose Abreu wrote:
> > > [ As for now this is only for testing! ]
> > >
> > > This follows David Miller advice and tries to fix coalesce timer in
> > > multi-queue scenarios.
> > >
> > > We are now using per-queue coalesce values and per-queue TX timer. This
> > > assumes that tx_queues == rx_queues, which can not be necessarly true.
> > > Official patch will need to have this fixed.
> > >
> > > Coalesce timer default values was changed to 1ms and the coalesce frames
> > > to 25.
> > >
> > > Tested in B2B setup between XGMAC2 and GMAC5.
> >
> > Tested on Amlogic meson-axg-s400. No regression seen so far.
> > (arch/arm64/boot/dts/amlogic/meson-axg-s400.dts)
> >
> > As far as I understand from the device tree parsing, this platform (and all
> > other amlogic platforms) use single queue.
>
> Thanks for testing! I will send a formal patch once I get around
> the problem of rx queues != tx queues.
>
> >
> > ---
> >
> > Jose,
> >
> > On another topic doing iperf3 test on amlogic's devices we seen a strange
> > behavior.
> >
> > Doing Tx or Rx test usually works fine (700MBps to 900MBps depending on the
> > platform). However, when doing both Rx and Tx at the same time, We see the
> > Tx
> > throughput dropping significantly (~30MBps) and lot of TCP retries.
> >
> > Would you any idea what might be our problem ? or how to start investigating
> > this ?
> >
>
> I'm not able to reproduce this here but I'm using multiple queue.
> I will try with single queue. In the meantime please try this
> patch (it shall be applied directly on top of this RFT):
No notable change. Rx is fine but Tx:
[ 5] 3.00-4.00 sec 3.55 MBytes 29.8 Mbits/sec 51 12.7 KBytes
I suppose the problem as something to do with the retries. When doing Tx test
alone, we don't have such a things a throughput where we expect it to be.
By the way, your mailer (and its auto 80 column rule I suppose) made the patch
below a bit harder to apply
>
>
> --->8
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index ae26a6e8608e..1407975320aa 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -2210,8 +2210,7 @@ static int stmmac_init_dma_engine(struct
> stmmac_priv *priv)
> stmmac_init_tx_chan(priv, priv->ioaddr,
> priv->plat->dma_cfg,
> tx_q->dma_tx_phy, chan);
>
> - tx_q->tx_tail_addr = tx_q->dma_tx_phy +
> - (DMA_TX_SIZE * sizeof(struct dma_desc));
> + tx_q->tx_tail_addr = tx_q->dma_tx_phy;
> stmmac_set_tx_tail_ptr(priv, priv->ioaddr,
> tx_q->tx_tail_addr, chan);
> }
> @@ -3004,6 +3003,7 @@ static netdev_tx_t stmmac_tso_xmit(struct
> sk_buff *skb, struct net_device *dev)
>
> netdev_tx_sent_queue(netdev_get_tx_queue(dev, queue),
> skb->len);
>
> + tx_q->tx_tail_addr = tx_q->dma_tx_phy + (tx_q->cur_tx *
> sizeof(*desc));
> stmmac_set_tx_tail_ptr(priv, priv->ioaddr,
> tx_q->tx_tail_addr, queue);
>
> if (priv->tx_coal_timer && !tx_q->tx_timer_active) {
> @@ -3223,6 +3223,8 @@ static netdev_tx_t stmmac_xmit(struct
> sk_buff *skb, struct net_device *dev)
> netdev_tx_sent_queue(netdev_get_tx_queue(dev, queue),
> skb->len);
>
> stmmac_enable_dma_transmission(priv, priv->ioaddr);
> +
> + tx_q->tx_tail_addr = tx_q->dma_tx_phy + (tx_q->cur_tx *
> sizeof(*desc));
> stmmac_set_tx_tail_ptr(priv, priv->ioaddr,
> tx_q->tx_tail_addr, queue);
>
> if (priv->tx_coal_timer && !tx_q->tx_timer_active) {
> --->8
>
> Thanks and Best Regards,
> Jose Miguel Abreu
