From: Alexander Stein <alexander.stein@systec-electronic.com>
To: Jakob Unterwurzacher <jakob.unterwurzacher@theobroma-systems.com>
Cc: John Fastabend <john.fastabend@gmail.com>,
Dave Taht <dave.taht@gmail.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
"linux-can@vger.kernel.org" <linux-can@vger.kernel.org>,
Martin Elshuber <martin.elshuber@theobroma-systems.com>
Subject: Re: [bug, bisected] pfifo_fast causes packet reordering
Date: Mon, 19 Mar 2018 07:07:05 +0100 [thread overview]
Message-ID: <1950329.Eot9n0FZxY@ws-stein> (raw)
In-Reply-To: <340a6c54-6031-5522-98f5-eafdd3a37a38@theobroma-systems.com>
On Friday, March 16, 2018, 11:26:47 AM CET Jakob Unterwurzacher wrote:
> On 15.03.18 23:30, John Fastabend wrote:
> >> I have reproduced it using two USB network cards connected to each other. The test tool sends UDP packets containing a counter and listens on the other interface, it is available at
> >> https://github.com/jakob-tsd/pfifo_stress/blob/master/pfifo_stress.py
> >>
> >
> > Great thanks, can you also run this with taskset to bind to
> > a single CPU,
> >
> > # taskset 0x1 ./pifof_stress.py
> >
> > And let me know if you still see the OOO.
>
> Interesting. Looks like it depends on which core it runs on. CPU0 is
> clean, CPU1 is not.
>
> Clean: taskset --cpu-list 0 ./pfifo_stress.py
>
> Broken: taskset --cpu-list 1 ./pfifo_stress.py
>
> Maybe related: CPU0 is where USB interrupts are handled:
>
> > root@rk3399-q7:~# cat /proc/interrupts
> > CPU0 CPU1 CPU2 CPU3 CPU4 CPU5
> > 217: 2175353 0 0 0 0 0 GICv3 142 Level xhci-hcd:usb5
This reminds me somewhat of this thread: https://marc.info/?l=linux-can&m=148007442317274&w=2
Best regards,
Alexander
next prev parent reply other threads:[~2018-03-19 6:07 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-13 18:24 [bug, bisected] pfifo_fast causes packet reordering Jakob Unterwurzacher
2018-03-13 18:35 ` Dave Taht
2018-03-14 4:03 ` John Fastabend
2018-03-14 10:09 ` Jakob Unterwurzacher
2018-03-15 18:08 ` Jakob Unterwurzacher
2018-03-15 22:30 ` John Fastabend
2018-03-16 10:26 ` Jakob Unterwurzacher
2018-03-19 6:07 ` Alexander Stein [this message]
2018-03-19 12:32 ` Paolo Abeni
2018-03-19 12:56 ` Jakob Unterwurzacher
2018-03-21 10:01 ` Jakob Unterwurzacher
2018-03-21 18:43 ` John Fastabend
2018-03-21 19:44 ` Jakob Unterwurzacher
2018-03-21 20:52 ` John Fastabend
2018-03-22 10:16 ` Jakob Unterwurzacher
2018-03-24 14:26 ` John Fastabend
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