Re: [dpdk-dev] [dpdk-stable] [PATCH v4] mbuf: fix reset on mbuf free

[Olivier Matz <olivier.matz@6wind.com>]

Hi Ali,


On Mon, Jan 18, 2021 at 05:52:32PM +0000, Ali Alnubani wrote:
> Hi,
> (Sorry had to resend this to some recipients due to mail server problems).
> 
> Just confirming that I can still reproduce the regression with single core and 64B frames on other servers.

Many thanks for the feedback. Can you please detail what is the amount
of performance loss in percent, and confirm the test case? (I suppose it
is testpmd io forward).

Unfortunatly, I won't be able to spend a lot of time on this soon (sorry
for that). So I see at least these 2 options:

- postpone the patch again, until I can find more time to analyze
  and optimize
- apply the patch if the performance loss is acceptable compared to
  the added value of fixing a bug

Regards,
Olivier


> 
> - Ali
> 
> > -----Original Message-----
> > From: Ali Alnubani <alialnu@nvidia.com>
> > Sent: Friday, January 15, 2021 8:39 PM
> > To: David Marchand <david.marchand@redhat.com>; Olivier Matz
> > <olivier.matz@6wind.com>; Ferruh Yigit <ferruh.yigit@intel.com>;
> > zhaoyan.chen@intel.com
> > Cc: dev <dev@dpdk.org>; Andrew Rybchenko
> > <andrew.rybchenko@oktetlabs.ru>; Ananyev, Konstantin
> > <konstantin.ananyev@intel.com>; Morten Brørup
> > <mb@smartsharesystems.com>; ajitkhaparde@gmail.com; dpdk stable
> > <stable@dpdk.org>; Ajit Khaparde <ajit.khaparde@broadcom.com>
> > Subject: Re: [dpdk-stable] [PATCH v4] mbuf: fix reset on mbuf free
> > 
> > Hi,
> > Adding Ferruh and Zhaoyan,
> > 
> > > Ali,
> > >
> > > You reported some performance regression, did you confirm it?
> > > If I get no reply by monday, I'll proceed with this patch.
> > 
> > Sure I'll confirm by Monday.
> > 
> > Doesn't the regression also reproduce on the Lab's Intel servers?
> > Even though the check iol-intel-Performance isn't failing, I can see that the
> > throughput differences from expected for this patch are less than those of
> > another patch that was tested only 20 minutes earlier. Both patches were
> > applied to the same tree:
> > 
> > https://mails.dpdk.org/archives/test-report/2021-January/173927.html
> > > | 64         | 512     | 1.571                               |
> > 
> > https://mails.dpdk.org/archives/test-report/2021-January/173919.html
> > > | 64         | 512     | 2.698                               |
> > 
> > Assuming that pw86457 doesn't have an effect on this test, it looks to me
> > that this patch caused a regression in Intel hardware as well.
> > 
> > Can someone update the baseline's expected values for the Intel NICs and
> > rerun the test on this patch?
> > 
> > Thanks,
> > Ali