Re: [PATCH 3/3] net: hisilicon: new hip04 ethernet driver

Dear David

On 04/08/2014 02:53 AM, David Miller wrote:

quoted

+static void hip04_tx_reclaim(struct net_device *ndev, bool force)

  ...

quoted

+static void hip04_xmit_timer(unsigned long data)
+{
+	struct net_device *ndev = (void *) data;
+
+	hip04_tx_reclaim(ndev, false);
+}

  ...

quoted

+	mod_timer(&priv->txtimer, jiffies + RECLAIM_PERIOD);

And this is where I stop reading your driver, I've stated already that this
kind of reclaim scheme is unacceptable.

The kernel timers lack the granularity necessary to service TX reclaim
with a reasonable amount of latency.

You must use some kind of hardware notification of TX slots becomming
available, I find it totally impossible that a modern ethernet controller
was created without a TX done interrupt.

There is no tx_done interrupt, we may need some workaround.

Is it acceptable to use poll to reclaim the xmitted buffer.
And in the xmit calling napi_schedule.

Thanks