Subject: Re: [PATCH net-next] tg3: Add skb->xmit_more support

From: Rick Jones <[email-masked]>
Date: Mon, 13 Oct 2014 10:14:17 -0700

On 10/13/2014 09:48 AM, Eric Dumazet wrote:
> On Mon, 2014-10-13 at 09:21 -0700, Prashant Sreedharan wrote:
>> Ring TX doorbell only if xmit_more is not set or the queue is stopped.
>>
>> Suggested-by: Daniel Borkmann <[email-masked]>
>> Signed-off-by: Prashant Sreedharan <[email-masked]>
>> Signed-off-by: Michael Chan <[email-masked]>
>> ---
>>   drivers/net/ethernet/broadcom/tg3.c |   10 ++++++----
>>   1 files changed, 6 insertions(+), 4 deletions(-)
>
> Have you noticed any performance change ?
>
> I did the patch for bnx2x but got no real difference...

If ringing the doorbell is just a pio write, it may just get lost in the 
noise.  If though the programming model (or some sort of defect 
workaround) of the NIC requires a pio read of some sort when ringing the 
doorbell...

rick