Re: [PATCH net-next RFC 2/4] virtio-net: transmit napi

From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: Mon, 6 Mar 2017 12:50:19 -0500

quoted

quoted

  drivers/net/virtio_net.c | 73
++++++++++++++++++++++++++++++++++++++++--------
  1 file changed, 61 insertions(+), 12 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 8c21e9a4adc7..9a9031640179 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -33,6 +33,8 @@
  static int napi_weight = NAPI_POLL_WEIGHT;
  module_param(napi_weight, int, 0444);
  +static int napi_tx_weight = NAPI_POLL_WEIGHT;
+

Maybe we should use module_param for this? Or in the future, use
tx-frames-irq for a per-device configuration.

This option should eventually just go away, and napi tx become the
standard mode.

In the short term, while we evaluate it on varied workloads, a
module_param sounds good to me. In general that is frowned
upon, as it leads to different configuration interfaces for each
device driver. But that should not be a concern in this limited
case.

In any event, do we really need a TX weight at all?

I guess you tried this, but why doesn't it not work to just do
all TX work unconditionally in a NAPI poll pass?  This is how
we encourage all NIC drivers to handle this.