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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Pavel Pisa <pisa@fel.cvut.cz>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>,
	linux-rt-users@vger.kernel.org, Carsten Emde <c.emde@osadl.org>,
	linux-can@vger.kernel.org,
	Oliver Hartkopp <socketcan@hartkopp.net>,
	Jan Altenberg <Jan.Altenberg@osadl.org>,
	Pavel Hronek <hronepa1@fel.cvut.cz>
Subject: Re: CAN latency measuremet on AMD/Xilinx Zynq with PREEMP_RT - added threaded NAPI configuration
Date: Thu, 17 Apr 2025 10:12:54 +0200	[thread overview]
Message-ID: <20250417081254.EUqrBagT@linutronix.de> (raw)
In-Reply-To: <202503281304.47808.pisa@fel.cvut.cz>

On 2025-03-28 13:04:47 [+0100], Pavel Pisa wrote:
> Hello Marc and Sebastian,
> 
Hi Pavel,

…
> #!/bin/bash
> 
> NAPI_PRIO=80
> 
> if (( $# != 1 )); then
>   echo "Need 1 argument (value 0 or 1)" >&2
>   exit 1
> fi
> for ifc in can2 can3 can4 can5 ; do
>   echo $1 > /sys/class/net/$ifc/threaded
> done
> 
> if [ $1 -eq 1 ] ; then
>   PIDS=$(ps -e | grep -E napi/can[0-9]+-[0-9] | tr -s ' ' | cut -d ' ' -f2)
>   for pid in $PIDS ; do
>     echo "Setting RT priority $NAPI_PRIO for $pid"
>     chrt -f --pid $NAPI_PRIO $pid
>   done
> fi

The IRQ thread should be limited to one CPU which is the same where the
IRQ it itself is set to. I don't think that this done the NAPI thread
automatically so it is probably free floating in the system.

Sebastian

  reply	other threads:[~2025-04-17  8:12 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-28 15:29 Question for AMD/Xilinx Zynq PREEMP_RT configuration check, CAN latency measuremet and FOSDEM 2025 Pavel Pisa
2025-01-29 10:17 ` Sebastian Andrzej Siewior
2025-01-29 12:04   ` Pavel Pisa
2025-01-29 14:40     ` Sebastian Andrzej Siewior
2025-03-28 12:04     ` CAN latency measuremet on AMD/Xilinx Zynq with PREEMP_RT - added threaded NAPI configuration Pavel Pisa
2025-04-17  8:12       ` Sebastian Andrzej Siewior [this message]
2025-04-18 10:12         ` Pavel Pisa
2025-04-18 20:18           ` Oliver Hartkopp

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