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Date: Fri, 6 May 2022 16:39:33 +0530
From: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
To: Ferruh Yigit <ferruh.yigit@xilinx.com>
Cc: dev@dpdk.org
Subject: Re: [PATCH 4/5] net/cxgbe: track packets dropped by TP due to
 congestion
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On Thursday, May 05/05/22, 2022 at 17:28:55 +0100, Ferruh Yigit wrote:
> On 4/18/2022 11:24 PM, Rahul Lakkireddy wrote:
> > Rx packets can get dropped at TP due to congestion and this info
> > will not get propagated to MPS. Track these Rx dropped packets
> > in imissed counter. Also add xstats for these counters.
> > 
> > Signed-off-by: Rahul Lakkireddy<rahul.lakkireddy@chelsio.com>
> 
> What 'TP' stands for? As far as I understand it is a kind of FW (TP
> Microcode) but I didn't able to find any reference to it.

Transport Processor (TP) on the NIC delivers the incoming packets
from the wire to NIC's DMA engine to place the packets in Rx buffers.
TP sends signal towards the Multi-Port Switch (MPS) near the MAC when
the Rxqs run out of Rx buffers posted by driver. These MPS buffer drop
stats are already accounted for in imissed counters. However, if a
large number of Rxqs run out of Rx buffers simultaneously, then the
TP can start dropping packets by itself without informing to the MPS
if there is heavy congestion on the channel. These packets dropped by
TP that could not be informed to MPS are now being accounted for in
imissed counters in this patch.

Thanks,
Rahul