From: Stephen Hemminger <stephen@networkplumber.org>
To: Mikael R Carlsson <Mikael.R.Carlsson@tietoevry.com>
Cc: "users@dpdk.org" <users@dpdk.org>
Subject: Re: Configure timestamp source for dpdk-pdump on E810 and DPDK 19.11
Date: Fri, 6 May 2022 07:55:27 -0700
Message-ID: <20220506075527.2acefd5a@hermes.local> (raw)
In-Reply-To: <DU0PR04MB92261EA274F5EC329FE4E6CBA6C59@DU0PR04MB9226.eurprd04.prod.outlook.com>
On Fri, 6 May 2022 07:46:39 +0000
Mikael R Carlsson <Mikael.R.Carlsson@tietoevry.com> wrote:
> Hi!
>
> I am using a Intel E810-XXVDA4 and DPDK version 19.11. During troubleshooting we have captures outgoing traffic with dpdk-pdump:
>
> dpdk-pdump -- --pdump 'port=1,queue=*,tx-dev=/tmp/tx.pcap
>
> I have opened the pcap-file in wireshark and I can see that some packets are delayed. However, system behavior indicates that the delays I see in the pcap file are not correct, they are too big. My questions is, how is the timestamp on packets in the pcap from dpdk-pdump created, like NIC HW generated, CPU time at disk write etc. or something else? Are there any run-time or build-time options to change the source of the timestamps?
>
> / Mikael
>
>
>
The timestamp for packet capture in DPDK is done when packet is queued to
the device. It is not possible with current driver architecture to get
timestamp when/after the packet was transmitted.
next prev parent reply other threads:[~2022-05-06 14:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-06 7:46 Mikael R Carlsson
2022-05-06 14:55 ` Stephen Hemminger [this message]
2022-05-06 15:02 ` Stephen Hemminger
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