LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Matteo Croce <mcroce@redhat.com>
Cc: Antoine Tenart <antoine.tenart@bootlin.com>,
	netdev <netdev@vger.kernel.org>,
	"gregory.clement@bootlin.com" <gregory.clement@bootlin.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Maxime Chevallier <maxime.chevallier@bootlin.com>,
	Nadav Haklai <nadavh@marvell.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	"miquel.raynal@bootlin.com" <miquel.raynal@bootlin.com>,
	Stefan Chulski <stefanc@marvell.com>,
	Marcin Wojtas <mw@semihalf.com>,
	"David S . Miller" <davem@davemloft.net>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [EXT] Re: [PATCH net-next 3/5] net: mvpp2: cls: Use RSS contexts to handle RSS tables
Date: Sat, 9 May 2020 14:51:05 +0100	[thread overview]
Message-ID: <20200509135105.GE1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <CAGnkfhx8fEZCoLPzGxSzQnj1ZWcQtBMn+g_jO1Jxc4zF7pQwjQ@mail.gmail.com>

On Sat, May 09, 2020 at 03:14:05PM +0200, Matteo Croce wrote:
> On Sat, May 9, 2020 at 1:45 PM Russell King - ARM Linux admin
> <linux@armlinux.org.uk> wrote:
> >
> > On Sat, May 09, 2020 at 11:15:58AM +0000, Stefan Chulski wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: Matteo Croce <mcroce@redhat.com>
> > > > Sent: Saturday, May 9, 2020 3:13 AM
> > > > To: David S . Miller <davem@davemloft.net>
> > > > Cc: Maxime Chevallier <maxime.chevallier@bootlin.com>; netdev
> > > > <netdev@vger.kernel.org>; LKML <linux-kernel@vger.kernel.org>; Antoine
> > > > Tenart <antoine.tenart@bootlin.com>; Thomas Petazzoni
> > > > <thomas.petazzoni@bootlin.com>; gregory.clement@bootlin.com;
> > > > miquel.raynal@bootlin.com; Nadav Haklai <nadavh@marvell.com>; Stefan
> > > > Chulski <stefanc@marvell.com>; Marcin Wojtas <mw@semihalf.com>; Linux
> > > > ARM <linux-arm-kernel@lists.infradead.org>; Russell King - ARM Linux admin
> > > > <linux@armlinux.org.uk>
> > > > Subject: [EXT] Re: [PATCH net-next 3/5] net: mvpp2: cls: Use RSS contexts to
> > > > handle RSS tables
> > > >
> > > > Hi,
> > > >
> > > > What do you think about temporarily disabling it like this?
> > > >
> > > > --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> > > > +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> > > > @@ -5775,7 +5775,8 @@ static int mvpp2_port_probe(struct platform_device
> > > > *pdev,
> > > >                             NETIF_F_HW_VLAN_CTAG_FILTER;
> > > >
> > > >         if (mvpp22_rss_is_supported()) {
> > > > -               dev->hw_features |= NETIF_F_RXHASH;
> > > > +               if (port->phy_interface != PHY_INTERFACE_MODE_SGMII)
> > > > +                       dev->hw_features |= NETIF_F_RXHASH;
> > > >                 dev->features |= NETIF_F_NTUPLE;
> > > >         }
> > > >
> > > >
> > > > David, is this "workaround" too bad to get accepted?
> > >
> > > Not sure that RSS related to physical interface(SGMII), better just remove NETIF_F_RXHASH as "workaround".
> >
> > Hmm, I'm not sure this is the right way forward.  This patch has the
> > effect of disabling:
> >
> > d33ec4525007 ("net: mvpp2: add an RSS classification step for each flow")
> >
> > but the commit you're pointing at which caused the regression is:
> >
> > 895586d5dc32 ("net: mvpp2: cls: Use RSS contexts to handle RSS tables")
> >
> >
> 
> Hi,
> 
> When git bisect pointed to 895586d5dc32 ("net: mvpp2: cls: Use RSS
> contexts to handle RSS tables"), which was merged
> almost an year after d33ec4525007 ("net: mvpp2: add an RSS
> classification step for each flow"), so I assume that between these
> two commits either the feature was working or it was disable and we
> didn't notice
> 
> Without knowing what was happening, which commit should my Fixes tag point to?

Let me make sure that I get this clear:

- Prior to 895586d5dc32, you can turn on and off rxhash without issue
  on any port.
- After 895586d5dc32, turning rxhash on eth2 prevents reception.

Prior to 895586d5dc32, with rxhash on, it looks like hashing using
CRC32 is supported but only one context.  So, if it's possible to
enable rxhash on any port on the mcbin without 895586d5dc32, and the
port continues to work, I'd say the bug was introduced by
895586d5dc32.

Of course, that would be reinforced if there was a measurable
difference in performance due to rxhash on each port.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up

  reply	other threads:[~2020-05-09 13:51 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-24 10:05 [PATCH net-next 0/5] net: mvpp2: Classifier updates, RSS Maxime Chevallier
2019-05-24 10:05 ` [PATCH net-next 1/5] net: mvpp2: cls: Use the correct number of rules in various places Maxime Chevallier
2019-05-24 10:05 ` [PATCH net-next 2/5] net: mvpp2: cls: Bypass C2 internals FIFOs at init Maxime Chevallier
2019-05-24 10:05 ` [PATCH net-next 3/5] net: mvpp2: cls: Use RSS contexts to handle RSS tables Maxime Chevallier
2020-04-13 23:43   ` Matteo Croce
2020-04-23 17:00     ` Russell King - ARM Linux admin
2020-05-09  0:12       ` Matteo Croce
2020-05-09 11:15         ` [EXT] " Stefan Chulski
2020-05-09 11:45           ` Russell King - ARM Linux admin
2020-05-09 12:16             ` Thomas Petazzoni
2020-05-09 12:48               ` Russell King - ARM Linux admin
2020-05-09 13:10                 ` Thomas Petazzoni
2020-05-09 13:14             ` Matteo Croce
2020-05-09 13:51               ` Russell King - ARM Linux admin [this message]
2020-05-09 14:48                 ` Russell King - ARM Linux admin
2020-05-09 15:31                   ` Matteo Croce
2020-05-09 19:52               ` Russell King - ARM Linux admin
2020-05-09 20:20                 ` Russell King - ARM Linux admin
2020-05-19  9:53                   ` Russell King - ARM Linux admin
2020-05-19 10:05                     ` Matteo Croce
2020-05-19 17:05                       ` Matteo Croce
2020-05-20 11:10                         ` Russell King - ARM Linux admin
2020-05-20 11:16                           ` Matteo Croce
2020-05-20 11:18                             ` Russell King - ARM Linux admin
2020-05-09 12:16           ` Matteo Croce
2020-05-09 12:31             ` Stefan Chulski
2020-05-09 13:25               ` Russell King - ARM Linux admin
2019-05-24 10:05 ` [PATCH net-next 4/5] net: mvpp2: cls: Extract the RSS context when parsing the ethtool rule Maxime Chevallier
2019-05-24 10:05 ` [PATCH net-next 5/5] net: mvpp2: cls: Support steering to RSS contexts Maxime Chevallier
2019-05-25 23:38 ` [PATCH net-next 0/5] net: mvpp2: Classifier updates, RSS David Miller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200509135105.GE1551@shell.armlinux.org.uk \
    --to=linux@armlinux.org.uk \
    --cc=antoine.tenart@bootlin.com \
    --cc=davem@davemloft.net \
    --cc=gregory.clement@bootlin.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maxime.chevallier@bootlin.com \
    --cc=mcroce@redhat.com \
    --cc=miquel.raynal@bootlin.com \
    --cc=mw@semihalf.com \
    --cc=nadavh@marvell.com \
    --cc=netdev@vger.kernel.org \
    --cc=stefanc@marvell.com \
    --cc=thomas.petazzoni@bootlin.com \
    --subject='Re: [EXT] Re: [PATCH net-next 3/5] net: mvpp2: cls: Use RSS contexts to handle RSS tables' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).