linux-kernel - Re: [PATCH net-next] r8152: divide the tx and rx bottom functions

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Message-ID: <9749764d-7815-b673-0fc4-22475601efec@gmail.com>
Date:   Fri, 16 Aug 2019 08:39:54 +0200
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Hayes Wang <hayeswang@...ltek.com>, netdev@...r.kernel.org
Cc:     nic_swsd@...ltek.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next] r8152: divide the tx and rx bottom functions



On 8/14/19 10:30 AM, Hayes Wang wrote:
> Move the tx bottom function from NAPI to a new tasklet. Then, for
> multi-cores, the bottom functions of tx and rx may be run at same
> time with different cores. This is used to improve performance.
> 
>  

tasklet and NAPI are scheduled on the same core (the current
cpu calling napi_schedule() or tasklet_schedule())

I would rather not add this dubious tasklet, and instead try to understand
what is wrong in this driver ;)

The various napi_schedule() calls are suspect IMO.

Also rtl8152_start_xmit() uses skb_queue_tail(&tp->tx_queue, skb);

But I see nothing really kicking the transmit if tx_free is empty ?

tx_bottom() is only called from bottom_half() (called from r8152_poll())