On 19.05.2022 17:52:36, Michael Anochin wrote: > my application continuously sends 64 bytes CANFD packets with 1MBit/s at the > 10ms interval. I use tcan4450 on the RPI4 with 5.10.103 Kernel and raspbian. > No other significant processes load the CPU. > > When I monitor the traffic with a PCAN adapter on a Windows PC, I notice > that the packets sometimes arrive with a delay of 5-9ms. But the next > following packet arrive faster as 10ms. My desired interval of 10ms is kept > at the jitter of +/- 9ms. > > Running the App on only one CPU core using tasksel improve the jitter > somewhat. > > Am I the only one who observes such large jitter or is the m_can > implementation at Perepherie (spi) not so fast from the throughput and is > completely normal. > > Maybe I should switch to 5.17 kernel? On 5.17 there are bulk read/write > function for spi regmap. The tcan4x5x driver is not really optimized. Don't expect great performance with it. At least the newer kernel have some kind of optimization. There are a lot of further optimization opportunities which are already implemented in the mcp251xfd driver. regards, Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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