Folks, I have a problem that manifests itself with SMP kernels ( tried both 2.2.5 and 2.2.11 ). I am working on a device driver that generates an interrupt when data is available. In my interrupt handler I call queue_task to place a task in the tq_scheduler queue because I want the processing to take place outside the context of an interrupt handler. With the UP kernel this scheme works fine, unfortunately with the SMP kernel if there's no I/O going on, the scheduler does not get run as frequently as I would wish ( runs at about every 10 ticks which is too slow for me) and hence my processing grinds down to unacceptable levels. It's funny because I can get this thing to run faster by moving my mouse around, the faster I move it the faster the processing :-) Maybe I need a crank on the side of my box. :-) Well here's my question: Can you tickle the scheduler to run immediately and can you pull this trick from an interrupt handler? Things that won't work: - Calling schedule() from the interrupt handler. - Starting a new task at system initialization using the task_queue mechanism that gets run once and waits on a wait queue loop for a wake_up from the interrupt handler. It appears that a task queue task is not allowed to sleep on a wait queue. (This is assuming that the scheduler will run if there's something on a wait queue and someone wakes it up). - Changing the value of HZ. Not unless you tell me a way of doing this without recompiling the kernel. One possible solution would have been to start a kernel thread that waits on a wait queue loop. I guess you don't have kernel threads in Linux (or do you?) so that's out. You could also start a user thread that calls a special ioctl that sleeps on a wait queue that gets woken by the interrupt handler but that's a really ugly hack. Any ideas? Thanks in advance. Gokhan Sozmen HotBot - Search smarter. http://www.hotbot.com - Linux SMP list: FIRST see FAQ at http://www.irisa.fr/prive/mentre/smp-faq/ To Unsubscribe: send "unsubscribe linux-smp" to [EMAIL PROTECTED]
