Date: Wed, 26 Mar 2014 00:21:38 +0100 From: Markus Gebert <markus.gebert@hostpoint.ch> To: Christopher Forgeron <csforgeron@gmail.com> Cc: FreeBSD Net <freebsd-net@freebsd.org>, Rick Macklem <rmacklem@uoguelph.ca>, Garrett Wollman <wollman@freebsd.org>, Jack Vogel <jfvogel@gmail.com> Subject: Re: 9.2 ixgbe tx queue hang Message-ID: <1197F2E5-F20C-43E4-B8C8-8732F45457C2@hostpoint.ch> In-Reply-To: <CAB2_NwA2zp9VaBm4ZRR1udghbSpSDs_x8bK6CPHCaBuiBKD=KA@mail.gmail.com> References: <0BC10908-2081-45AC-A1C8-14220D81EC0A@hostpoint.ch> <1236110257.2510701.1395709458870.JavaMail.root@uoguelph.ca> <CAB2_NwBrdp3XsVrgkWgf7zGsrCBq1%2BC7FgsYvV28yjcUe4qZ=Q@mail.gmail.com> <CAB2_NwA2zp9VaBm4ZRR1udghbSpSDs_x8bK6CPHCaBuiBKD=KA@mail.gmail.com>
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On 26.03.2014, at 00:06, Christopher Forgeron <csforgeron@gmail.com> wrote:
> Update:
>
> I'm changing my mind, and I believe Rick's TSO patch is fixing things
> (sorry). In looking at my notes, it's possible I had lagg on for those
> tests. lagg does seem to negate the TSO patch in my case.
I’m glad to hear you could check that scenario again. In the other email I just sent, I just asked you to redo this test. Now it makes perfect sense why you saw oversized packets despite Rick’s if_hw_tsomax patch.
> kernel.10stable_basicTSO_65535/
>
> - IP_MAXPACKET = 65535;
> - manually forced (no if statement) ifp->if_hw_tsomax = IP_MAXPACKET -
> (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN);
> - Verified on boot via printf that ifp->if_hw_tsomax = 65517
Is 65517 correct? With Ricks patch, I get this:
dev.ix.0.hw_tsomax: 65518
Also the dtrace command you used excludes 65518...
> - Boot in a NON LAGG environment. ix0 only.
>
> ixgbe's printf is showing packets up to 65530. Haven't run long enough yet
> to see if anything will go over 65535
>
> I have this tcpdump running to check packet size.
> tcpdump -ennvvXS -i ix0 greater 65518
>
> I do expect to get packets over 65518, but I was just curious to see if any
> of them would go over 65535. Time will tell.
>
> In a separate test, If I enable lagg, we have LOTS of oversized packet
> problems. It looks like tsomax is definitely not making it through in
> if_lagg.c - Any recommendations there? I will eventually need lagg, as I'm
> sure will others.
I think somebody has to invent a way to propagate if_hw_maxtso to interfaces on top of each other.
> With dtrace, it's showing t_tsomax >= 65518. Shouldn't that not be
> happening?
Looks like these all come from bce interfaces (bce_intr in the stack trace), which probably have another value for if_hw_tsomax.
Markus
> dtrace -n 'fbt::tcp_output:entry / args[0]->t_tsomax != 0 &&
> args[0]->t_tsomax >= 65518 / { printf("unexpected tp->t_tsomax: %i\n",
> args[0]->t_tsomax); stack(); }'
>
>
> 6 31403 tcp_output:entry unexpected tp->t_tsomax: 65535
>
> kernel`tcp_do_segment+0x2c99
> kernel`tcp_input+0x11a2
> kernel`ip_input+0xa2
> kernel`netisr_dispatch_src+0x5e
> kernel`ether_demux+0x12a
> kernel`ether_nh_input+0x35f
> kernel`netisr_dispatch_src+0x5e
> kernel`bce_intr+0x765
> kernel`intr_event_execute_handlers+0xab
> kernel`ithread_loop+0x96
> kernel`fork_exit+0x9a
> kernel`0xffffffff80c75b2e
>
> 3 31403 tcp_output:entry unexpected tp->t_tsomax: 65535
>
> kernel`tcp_do_segment+0x2c99
> kernel`tcp_input+0x11a2
> kernel`ip_input+0xa2
> kernel`netisr_dispatch_src+0x5e
> kernel`ether_demux+0x12a
> kernel`ether_nh_input+0x35f
> kernel`netisr_dispatch_src+0x5e
> kernel`bce_intr+0x765
> kernel`intr_event_execute_handlers+0xab
> kernel`ithread_loop+0x96
> kernel`fork_exit+0x9a
> kernel`0xffffffff80c75b2e
>
> 6 31403 tcp_output:entry unexpected tp->t_tsomax: 65535
>
> kernel`tcp_do_segment+0x2c99
> kernel`tcp_input+0x11a2
> kernel`ip_input+0xa2
> kernel`netisr_dispatch_src+0x5e
> kernel`ether_demux+0x12a
> kernel`ether_nh_input+0x35f
> kernel`netisr_dispatch_src+0x5e
> kernel`bce_intr+0x765
> kernel`intr_event_execute_handlers+0xab
> kernel`ithread_loop+0x96
> kernel`fork_exit+0x9a
> kernel`0xffffffff80c75b2e
>
> 1 31403 tcp_output:entry unexpected tp->t_tsomax: 65535
>
> kernel`tcp_do_segment+0x2c99
> kernel`tcp_input+0x11a2
> kernel`ip_input+0xa2
> kernel`netisr_dispatch_src+0x5e
> kernel`ether_demux+0x12a
> kernel`ether_nh_input+0x35f
> kernel`netisr_dispatch_src+0x5e
> kernel`bce_intr+0x765
> kernel`intr_event_execute_handlers+0xab
> kernel`ithread_loop+0x96
> kernel`fork_exit+0x9a
> kernel`0xffffffff80c75b2e
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