netdev - Re: [PATCH] sis900: re-enable high throughput

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Message-Id: <20190609.193332.1303109263918456859.davem@davemloft.net>
Date:   Sun, 09 Jun 2019 19:33:32 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     eric.dumazet@...il.com
Cc:     sergej.benilov@...glemail.com, venza@...wnhat.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH] sis900: re-enable high throughput

From: Eric Dumazet <eric.dumazet@...il.com>
Date: Fri, 7 Jun 2019 12:18:21 -0700

> Note that this suggests the driver is not performing TX completion
> fast enough.
> 
> Looking at the driver, I do not see anything requesting interrupt
> mitigation, so this might also be caused by a race in the driver
> (some skbs being not TX completed until another unrelated xmit is
> requested)

I think the INTR bit needs to be set in the individual TX descriptors.

This is a classic case of a chip that only interrupts when the entire
TX queue is emptied and the TX engine enters the idle state.

I don't like this skb_orphan() solution as it kills UDP flow control.

I'm not applying this.