[dpdk-dev] [PATCH] ixgbe: do not include CRC in Tx byte count

[Ananyev, Konstantin]

Hi Stephen,

> -----Original Message-----
> From: Stephen Hemminger [mailto:stephen at networkplumber.org]
> Sent: Tuesday, March 24, 2015 3:55 PM
> To: Ananyev, Konstantin
> Cc: dev at dpdk.org; Stephen Hemminger
> Subject: Re: [dpdk-dev] [PATCH] ixgbe: do not include CRC in Tx byte count
> 
> On Mon, 23 Mar 2015 16:45:44 +0000
> "Ananyev, Konstantin" <konstantin.ananyev at intel.com> wrote:
> 
> >
> >
> > > -----Original Message-----
> > > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of stephen at networkplumber.org
> > > Sent: Friday, January 23, 2015 6:24 AM
> > > To: dev at dpdk.org
> > > Cc: Stephen Hemminger
> > > Subject: [dpdk-dev] [PATCH] ixgbe: do not include CRC in Tx byte count
> > >
> > > From: Stephen Hemminger <shemming at brocade.com>
> > >
> > > The ixgbe driver was including CRC in the transmit packet byte
> > > count, but not for packets received.
> > > This was notice when forwarding and
> > > the number of bytes received was greater than the number of bytes transmitted
> > > for the same number of packets. Make the driver behave like other
> > > virtual devices and not include CRC in byte count. Use the same queue
> > > counters already computed and used for Rx.
> >
> > About RX side stats - as I remember it depends to what value hw_stip_crc is set at configure().
> > If hw_stip_crc==1, then, yes CRC bytes are not included into  QBRC value.
> > I If hw_stip_crc==0, then CRC bytes are included into QBRC.
> 
> That is an additional bug!
>   * CRC should never be included in the byte count.
>     This is not how Linux or other drivers report byte count.

I don't have any strong opinion here...
For me any method (with or without CRC) of counting bytes are ok, as long as this method is identical across all PMDs we support.
Which makes we wonder, what approach other PMDs use? 

> 
>   * the byte count must be symmetrical Rx == Tx
> 
> The Brocade router always set strip_crc to 1. So did not see the additional bug
> of CRC being included in byte count.

Are you going to submit v2, to make Rx==Tx for both cases?
Konstantin

> 
>