Re: Intel E810 Performance Regression - ARM Grace Server

[Patrick Robb <probb@iol.unh.edu>]

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Hi Bruce,

Manit can identify the specific commit this morning.

You raise a good point about the descriptor count. It is worth us assessing
the performance with a broader set of descriptor counts and deciding what
set of test configurations will yield helpful results for developers going
forward. By my understanding, we want to test with a set of descriptor
counts which are basically appropriate for the given traffic flow, not the
other way around. We will gather more info this morning and share it back
to you.

On Thu, Jul 3, 2025 at 4:43 AM Richardson, Bruce <bruce.richardson@intel.com>
wrote:

> Hi Manit,
>
> Can you identify which patch exactly within the series is causing the
> regression? We were not expecting performance to change with the patchset,
> but obviously something got missed.
> I will follow up on our end to see if we see any regressions.
>
> I must say, though, that 512 entries is pretty small rings sizes to use
> for 100G traffic. The slightest stall would cause those rings to overflow.
> What is perf like at other ring sizes, e.g. 1k or 2k?
>
> /Bruce
>
>
> > -----Original Message-----
> > From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> > Sent: Thursday, July 3, 2025 8:03 AM
> > To: Manit Mahajan <mmahajan@iol.unh.edu>
> > Cc: Burakov, Anatoly <anatoly.burakov@intel.com>; ci@dpdk.org;
> Richardson,
> > Bruce <bruce.richardson@intel.com>; Wathsala Wathawana Vithanage
> > <wathsala.vithanage@arm.com>; Paul Szczepanek
> > <Paul.Szczepanek@arm.com>
> > Subject: Re: Intel E810 Performance Regression - ARM Grace Server
> >
> > + Wathsala, Paul
> >
> > > On Jul 2, 2025, at 10:09 PM, Manit Mahajan <mmahajan@iol.unh.edu>
> > wrote:
> > >
> > > Hi we have an update about the single core forwarding test on the ARM
> > Grace server with the E810 100G Ice card. There was an intel PMDs series
> that
> > was merged a week ago which had some performance failures when it was
> > going through the CI:
> > https://patches.dpdk.org/project/dpdk/patch/01c94afcb0b1c2795c031afc8
> > 72a8faf3f0db2b5.1749229651.git.anatoly.burakov@intel.com/
> > >
> > > and: http://mails.dpdk.org/archives/test-report/2025-June/883654.html
> > >
> > > As you can see it causes roughly a 6% decrease in packets forwarded in
> the
> > single core forwarding test with 64Byte frames and 512 txd/rxd. The delta
> > tolerance on the single core forwarding test is 5%, so a 6% reduction in
> MPPS
> > forwarded is a failure.
> > >
> > > This was merged into mainline 6 days ago, which is why some failures
> started
> > to come in this week for the E810 Grace test.
> > >
> > > To double check this, on DPDK I checked out to:
> > >
> > > test/event: fix event vector adapter timeouts
> > (2eca0f4cd5daf6cd54b8705f6f76f3003c923912) which directly precedes the
> > Intel PMD patchseries, and ran the test and it forwarded the
> pre-regression
> > MPPS that we expected.
> > >
> > > Then I checked out to net/intel: add common Tx mbuf recycle
> > (f5fd081c86ae415515ab55cbacf10c9c50536ca1)
> > >
> > > and I ran the test and it had the 6% reduction in MPPS forwarded.
> > >
> > > Another thing to note is that regrettably the ARM Grace E810 test did
> not get
> > run on the v7 (the final version) of this series, which meant the
> failure was not
> > displayed on that version and that's probably why it was merged. We will
> look
> > back into our job history and see why this test failed to report.
> > >
> > > Please let me know if you have any questions about the test, the
> testbed
> > environment info, or anything else.
> > Thanks Manit for looking into this. Adding few folks from Arm to follow
> up.
> >
> > >
> > > Thanks,
> > > Manit Mahajan
> >
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