Date: Fri, 20 Nov 2020 19:00:59 +0530 From: Rajesh Kumar <rajfbsd@gmail.com> To: Vincenzo Maffione <vmaffione@freebsd.org> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, FreeBSD Hackers <freebsd-hackers@freebsd.org>, stephan.dewt@yahoo.co.uk Subject: Re: Netmap bridge not working with 10G Ethernet ports Message-ID: <CAAO%2BANM_zUgViGfFRuxZo7bTTNd7w9Xco=ptZweYHSGgx_xXsg@mail.gmail.com> In-Reply-To: <CA%2B_eA9ixySZtvJ8C9mwPj6q2fAQmZJicVgLHKkpb398-u_PaJw@mail.gmail.com> References: <CAAO%2BANOg5MEfHf9bV5x4L_QXNY2O9vQk0s%2BJrD7yzeXCQfHt8w@mail.gmail.com> <CA%2B_eA9hR8ysiFGj-iriMpqXcDbc4X_h_C1sgNoO05KoLy5orCA@mail.gmail.com> <CAAO%2BANP3PcqKo1nUfZTB92uKoJ40VA9YLo9MMqSN9AkMhq55tw@mail.gmail.com> <CA%2B_eA9ixySZtvJ8C9mwPj6q2fAQmZJicVgLHKkpb398-u_PaJw@mail.gmail.com>
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Hi Vincenzo,
On Fri, Nov 20, 2020 at 3:20 AM Vincenzo Maffione <vmaffione@freebsd.org>
wrote:
>
> Ok, now it makes sense. Thanks for clarifying. I see that if_axp(4) uses
> iflib(4). This means that actually if_axp(4) has native netmap support,
> because iflib(4) has native netmap support.
>
>
It means that the driver has some modifications to allow netmap to directly
> program the NIC rings. These modifications are mostly the per-driver txsync
> and rxsyng routines.
> In case of iflib(4) drivers, these modifications are provided directly
> within the iflib(4) code, and therefore any driver using iflib will have
> native netmap support.
>
Thanks for clarifying on the Native Netmap support.
Ok, this makes sense, because also ix(4) uses iflib, and therefore you are
> basically hitting the same issue of if_axp(4)
> At this point I must think that there is still some issue with the
> interaction between iflib(4) and netmap(4).
>
Ok. Let me know if any more debug info needed in this part.
I see. This info may be useful. Have you tried to look at interrupts (e.g.
> `vmstat -i`), to see if "ix0" gets any RX interrupts (for the missing ARP
> replies)?
>
It's interesting here. When I try with Intel NIC card. I see atleast 1
interrupt raised. But not sure whether that is for ARP reply. Because,
when I try to dump the packet from "bridge"(modified) utility, I don't see
any ARP reply packet getting dumped.
*irq59: ix0:rxq0 1 0 (only 1 interrupt on
the opposite side)*irq67: ix0:aq 2 0
*irq68: ix1:rxq0 3 0 (you can see 3
interrupts for 3 ARP requests from System 1)*irq76: ix1:aq
2 0
The same experiment, when I try with AMD inbuilt ports, I don't see that 1
interrupt also raised.
irq81: ax0:dev_irq 16 0
irq83: ax0 2541 4
irq93: ax1:dev_irq 27 0
irq95: ax1 2371 3
*irq97: ax1:rxq0 3 0 (you can see 3
interrupts for 3 ARP requests from System 1, but no interrupt is seen from
"ax0:rxq0" for ARP reply from System 2)*
I will do some more testing to see whether this behavior is consistent or
intermittent.
Also the igb(4) driver is using iflib(4). So the involved netmap code is
> the same as ix(4) and if_axp(4).
> This is something that I'm not able to understand right now.
> It does not look like something related to offloads.
>
> Next week I will try to see if I can reproduce your issue with em(4), and
> report back. That's still an Intel driver using iflib(4).
>
The "igb(4)" driver, with which things are working now is related to em(4)
driver (may be for newer hardware version). Initially we faced similar
issue with igb(4) driver as well. After reverting the following commits,
things started to work. Thanks to Stephan Dewt (copied) for pointing
this. But it still fails with ix(4) driver and if_axp(4) driver.
https://github.com/freebsd/freebsd/commit/e12efc2c9e434075d0740e2e2e9e2fca2ad5f7cf
Thanks for providing your inputs on this issue Vincenzo. Let me know for
any more details that you need.
Thanks,
Rajesh.
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