RE: [EXT] Re: [PATCH net-next] net: mvpp2: Add parsing support for different IPv4 IHL values

[Stefan Chulski]

> -----Original Message-----
> From: Marcin Wojtas <mw@xxxxxxxxxxxx>
> Sent: Tuesday, April 13, 2021 12:59 PM
> To: Stefan Chulski <stefanc@xxxxxxxxxxx>
> Cc: Russell King - ARM Linux admin <linux@xxxxxxxxxxxxxxx>;
> netdev@xxxxxxxxxxxxxxx; thomas.petazzoni@xxxxxxxxxxx;
> davem@xxxxxxxxxxxxx; Nadav Haklai <nadavh@xxxxxxxxxxx>; Yan
> Markman <ymarkman@xxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx;
> kuba@xxxxxxxxxx; andrew@xxxxxxx; atenart@xxxxxxxxxx; Liron Himi
> <lironh@xxxxxxxxxxx>; Dana Vardi <danat@xxxxxxxxxxx>
> Subject: Re: [EXT] Re: [PATCH net-next] net: mvpp2: Add parsing support for
> different IPv4 IHL values
> 
> Hi Stefan,
> 
> wt., 13 kwi 2021 o 11:56 Stefan Chulski <stefanc@xxxxxxxxxxx> napisał(a):
> >
> > > > -----Original Message-----
> > > > From: Russell King - ARM Linux admin <linux@xxxxxxxxxxxxxxx>
> > > > Sent: Tuesday, April 13, 2021 12:18 PM
> > > > To: Stefan Chulski <stefanc@xxxxxxxxxxx>
> > > > Cc: netdev@xxxxxxxxxxxxxxx; thomas.petazzoni@xxxxxxxxxxx;
> > > > davem@xxxxxxxxxxxxx; Nadav Haklai <nadavh@xxxxxxxxxxx>; Yan
> > > Markman
> > > > <ymarkman@xxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx;
> > > kuba@xxxxxxxxxx;
> > > > mw@xxxxxxxxxxxx; andrew@xxxxxxx; atenart@xxxxxxxxxx; Liron Himi
> > > > <lironh@xxxxxxxxxxx>; Dana Vardi <danat@xxxxxxxxxxx>
> > > > Subject: [EXT] Re: [PATCH net-next] net: mvpp2: Add parsing
> > > > support for different IPv4 IHL values
> > > >
> > > > External Email
> > > >
> > > > ------------------------------------------------------------------
> > > > ---- On Tue, Apr 13, 2021 at 11:45:31AM +0300, stefanc@xxxxxxxxxxx
> > > > wrote:
> > > > > From: Stefan Chulski <stefanc@xxxxxxxxxxx>
> > > > >
> > > > > Add parser entries for different IPv4 IHL values.
> > > > > Each entry will set the L4 header offset according to the IPv4 IHL field.
> > > > > L3 header offset will set during the parsing of the IPv4 protocol.
> > > >
> > > > What is the impact of this commit? Is something broken at the
> > > > moment, if so what? Does this need to be backported to stable
> kernels?
> > > >
> > > > These are key questions, of which the former two should be covered
> > > > in every commit message so that the reason for the change can be
> known.
> > > > It's no good just describing what is being changed in the commit
> > > > without also describing why the change is being made.
> > > >
> > > > Thanks.
> > >
> > > Due to missed parser support for IP header length > 20, RX IPv4
> > > checksum offload fail.
> > >
> > > Regards.
> >
> > Currently driver set skb->ip_summed = CHECKSUM_NONE and checksum
> done by software.
> > So this just improve performance for packets with IP header length > 20.
> > IMO we can keep it in net-next.
> >
> > Stefan.
> 
> Please update the commit message in v2 with the explanation.
> 
> Also - is there an easy way to test it? L3 forwarding with forced header
> length?
> 
> Thanks,
> Marcin

I will wait for additional comments and resend it tomorrow.
We probably should see this in "perf top" in L3 forwarding. Less cycles consumed by Network stack checksum callback.

Regards.