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Userspace can signal with CAN_CTRLMODE_BERR_REPORTING whether they need reporting of bus errors (CAN_ERR_BUSERROR) or not. However, xilinx_can driver currently always sends CAN_ERR_BUSERROR frames to userspace on bus errors. To improve performance on error conditions when bus error reporting is not needed, avoid sending CAN_ERR_BUSERROR frames unless requested via CAN_CTRLMODE_BERR_REPORTING. The error interrupt is still kept enabled as there is no dedicated state transition interrupt, but just disabling error frame submission still yields a significant performance improvement. In a simple test with continuous bus errors and no userspace programs reading/writing CAN I saw system CPU load reduced by 1/3. Tested on a ZynqMP board with CAN-FD v1.0. Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.