On Thu, Apr 1, 2021 at 2:05 AM Kathleen Capella
[off-list ref] wrote:

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-----Original Message-----
From: Honnappa Nagarahalli <redacted>
Sent: Thursday, March 11, 2021 11:00 AM
To: thomas@monjalon.net
Cc: Jerin Jacob <redacted>; dev@dpdk.org; Kathleen Capella
[off-list ref]; Dharmik Thakkar
[off-list ref]; Ruifeng Wang [off-list ref];
david.marchand@redhat.com; Bruce Richardson
[off-list ref]; jerinj@marvell.com;
hemant.agrawal@nxp.com; Ferruh Yigit [off-list ref]; Ananyev,
Konstantin [off-list ref]; Stephen Hemminger
[off-list ref]; nd [off-list ref]; nd [off-list ref]
Subject: RE: [dpdk-dev] L3fwd mode in testpmd

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On Thu, Mar 11, 2021 at 12:01 AM Honnappa Nagarahalli
[off-list ref] wrote:

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Hello,
        Performance of L3fwd example application is one of the
key

benchmarks in DPDK. However, the application does not have many
debugging statistics to understand the performance issues. We have
added L3fwd as another mode/stream to testpmd which provides

enough

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statistics at various levels. This has allowed us to debug the
performance issues effectively.

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There is more work to be done to get it to upstreamable state. I
am

wondering if such a patch is helpful for others and if the
community would be interested in taking a look. Please let me know

what you think.

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We are using app/proc-info/ to attach and analyze the performance.
That helps to analyze the unmodified application. I think, if
something is missing in proc-info app, in my opinion it is better
to enhance proc-info so that it can help other third-party applications.

Just my 2c.

Thanks Jerin. We will explore that.

I agree it is dangerous to rely too much on testpmd for everything.
Please tell us what in testpmd could be useful out of it.

Things that are very helpful in testpmd are: 1) HW statistics from the NIC 2)
Forwarding stats 3) Burst stats (indication of headroom availability) 4) Easy to
set parameters like RX and TX queue depths (among others) without having
to recompile.

[Kathleen Capella]
Thank you for the suggestion of app/proc-info. I've tried it out with
l3fwd and see that it does have the HW stats from the NIC and the forwarding stats.
However, it does not have the burst stats testpmd offers, nor the

One option to see such  level of debugging would be to have
- Create a memzone in the primary process
- Application under test can update the stats in memzone based on the code flow
- proc-info can read the counters updated by application under test
using the memzone object got through rte_memzone_lookup()

Another approach will be using rte_trace()[1] for debugging/tracing by
adding tracepoints in l3fwd for such events.
It has a timestamp and the trace format is opensource trace
format(CTF(Common trace format)), so that we can use
post posting tools to analyze.
[1]
https://doc.dpdk.org/guides/prog_guide/trace_lib.html

ability to easily change parameters without having to recompile,
which helps reduce debugging time significantly.