On 18.01.22 07:35, 孙世龙 sunshilong via Xenomai wrote:
Hi, listsAnd I clearly know that writing to file could not be guaranteed to be completed in a limited duration(i.e. before a specific deadline). Since logging information during the execution of real-time tasks can help me understand what lead to a bug or crash, so my question is how can I write neccerary logs for real-time tasks? As far as I know, I can achieve this goal by 1. write the log in real-time thread by XDDP or write the log to a block of already allocated memory 2. read out the said log in non-real-time thread and write them to a file Is there any better method? Thank you for your attention to this matter.
You could also use fprintf() or syslog() as provided by libcobalt. That will provide the required decoupling from the RT thread providing the message and a non-RT writer thread dumping it to a non-RT output channel. One difference to the XDDP-based approach is that it is event-driven while printf & Co. uses a polling non-RT thread to empty the queue. Both approaches have pros and cons, depending on your workload.
Jan -- Siemens AG, Technology Competence Center Embedded Linux
