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From: Stephen Hemminger <stephen@networkplumber.org>
To: Sun Yalou <sunyalou@bupt.edu.cn>
Cc: users@dpdk.org
Subject: Re: 82599ES 10-Gigabit NIC cannot at 10G speed for a long time
Date: Tue, 29 Nov 2022 09:05:59 -0800	[thread overview]
Message-ID: <20221129090559.5d5fe72a@hermes.local> (raw)
In-Reply-To: <8eaf46e68801e.ec7ca303cc0d3@bupt.edu.cn>

On Thu, 24 Nov 2022 04:42:06 +0000
Sun Yalou <sunyalou@bupt.edu.cn> wrote:

> Hi there,I'm developing a custom virtual switch using OVS-DPDK(v19.11.10). 
> In order to achieve 10Gbit/s, I modified the OVS pmd mode from 
> run-to-completion to pipeline. I used 1 thread as rx thread, 4 threads as 
> worker thread and 1 thread as tx thread. it's a load balance archiecture.
> I found the forwarding rate can reach 10Gbit/s in first 2 minite, and then 
> drop to 5Gbit/s . My traffic generator keeps send packets at 10G rate. I 
> debugged and found that packet loss occurred in `rte_eth_tx_burst`, then it 
> invoke `ixgbe_xmit_pkts_vec` -> `ixgbe_xmit_fixed_burst_vec` , in 
> `ixgbe_xmit_fixed_burst_vec`it should be `txq->nb_tx_free` < `nb_pkts`, it 
> means there is not enough TX descriptor to be allocated.
> I have tried increasing socket-mem when starting program and reducing the 
> size of batch sent, neither worked. I wonder if i am missing something 
> important? This question has been bugging me for weeks.
> Does anyone know this issue? Thanks, BR, Yalou


Curious why you think pipeline is faster, since processing same
packet repeatedly by multiple cores causes cache misses.

      reply	other threads:[~2022-11-29 17:06 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-24  4:42 Sun Yalou
2022-11-29 17:05 ` Stephen Hemminger [this message]

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