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

[Thomas Monjalon <thomas.monjalon@6wind.com>]

Anyone to carefully review this patch?

2015-01-27 11:38, Stephen Hemminger:
> On Tue, 27 Jan 2015 11:11:39 +0100
> Thomas Monjalon <thomas.monjalon@6wind.com> wrote:
> 
> > Hi Stephen,
> > 
> > 2015-01-22 22:23, stephen@networkplumber.org:
> > > From: Stephen Hemminger <shemming@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
> > 
> > Tx includes CRC and Rx count is greater, really?

ping

> > > 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.
> > 
> > Please could you describe the difference between gptc/gotc and qptc/qbtc?
> > 
> > Thank you
> 
> 
> The byte counts for global registers include CRC in the byte count.
> This has been observed by experimentation and validated by QA and documented
> in Intel HW specs.
> 
> The original code used queue counts for Rx because the global counters
> include missed packets (which must not be included in the ipacket counts).
> I suspect that is why the original developer used the queue counts, as
> a good side effect the Rx byte count was correct (no CRC). I just extended
> this for Tx.