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

Butler, Siobhan A siobhan.a.butler at intel.com
Thu Apr 2 22:20:17 CEST 2015



> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Stephen
> Hemminger
> 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.
> 
>   * 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.
> 
> 
Great to see some discussion here all but can we hold on to the patch until after the 2.0 package is made so there is enough time to review and test it properly?
Thanks 
Siobhan
<siobhan.a.butler at intel.com>


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