I'm taking a crack at implementing this task. I'm doing it more for self education than any rw need. Though I know from personnel experience how valuable tracing can be. The requirements for this task state: "When analysing things like VM caching performance or filesystem layout policies, it is useful to be able to capture a trace of certain kinds of activity for quite large workloads. Modern disks can write a fair number of megabytes per second, which should be enough for this purpose. The idea basically: Implement a large ring-buffer, at places where tracing is desired data is appended to the ring-buffer. A kernel thread flushes the buffer to a raw disk-partition as fast as possible." I've figured out how to address most all of this job with the exception of raw disk I/O from a kernel thread. The kernel documentation is rich with info on user mode to kernel mode IPC. From what I've read, I believe I have to use the "raw" character driver bound to a mounted block device (disk). I'm sure I can wade through getting this set up. However I'm lost when it comes to accessing the raw device (/dev/raw1) from within a kernel thread. Any help/pointers are greatly appreciated. - Dennis - -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
