[dpdk-dev] igb PMD should set the default tx wthresh correctly.

[Lu, Wenzhuo]

Hi,

> -----Original Message-----
> From: Wiles, Keith
> Sent: Friday, July 17, 2015 7:06 PM
> To: Thomas Monjalon; Stephen Hemminger; Lu, Wenzhuo
> Cc: dev at dpdk.org
> Subject: Re: [dpdk-dev] igb PMD should set the default tx wthresh correctly.
> 
> 
> 
> On 7/17/15, 9:15 AM, "dev on behalf of Thomas Monjalon"
> <dev-bounces at dpdk.org on behalf of thomas.monjalon at 6wind.com> wrote:
> 
> >2015-07-16 19:49, Stephen Hemminger:
> >> On Fri, 17 Jul 2015 00:52:09 +0000
> >> "Lu, Wenzhuo" <wenzhuo.lu at intel.com> wrote:
> >>
> >> > Hi Stephen,
> >> > I don't think there's a conflict. The message just reminder us that
> >>we can adjust the values to achieve better performance.
> >> > I saw ixgbe and i40e also use 0 as the same default value. To my
> >>opinion, it's good to keep the same behavior.
> >> > Thanks.
> >>
> >> In my opnion, no application should have to make special case setup
> >>for each device type. Having to have a table that lists all the
> >>parameters  for each device name is not supportable or scaleable.
> >>
> >> The DPDK started out as "lets do benchmarks fast" but as a production
> >> toolkit it needs to stop having this kind of thing.
> >>
> >> The message shows up to the end-user, who thinks it is a driver bug.
> >> The "us" is now real customers not DPDK developers.
> >
> >+1 to have better default values and less scary messages.
> +1 I agree we should have default values. The scary message is for
> debugging only in the best of cases and just wrong for the normal case.
After checking the code,  igb and ixgbe/i40e's behavior is different for  tx_rs_thresh
and tx wthresh, so now I think it's no necessary to let them have the same default value.
Agree that we shall remove the message or set an appropriate value for tx wthresh.
> >