Em Wed, Nov 28, 2007 at 08:12:24AM -0600, K.R. Foley escreveu: > John Sigler wrote: > > Hello Steven, > > > > Steven Rostedt wrote: > > > >> John Sigler wrote: > >> > >>> I need to change the priorities of several soft and hard IRQ handlers. > >>> > >>> Namely, > >>> > >>> o reduce the prio of "softirq-timer" handler to 10 > >>> > >>> o reduce the prio of IRQ14 and IRQ15 handlers to 20 > >>> (my flash drives do not support DMA BTW...) > >>> > >>> o boost the prio of my I/O boards' IRQ handlers to 60 > >>> (there can be 1 or 2 boards, the driver is a kernel module > >>> which is loaded after the system has booted.) > >>> > >>> I've written a short program that calls > >>> sched_setscheduler(pid, SCHED_FIFO, ¶m); > >>> with the appropriate pid, which I look up using ps -ef > >> > >> Look for the program "chrt". It does this for you. This program is > >> available in all major distributions of Linux. > > > > Thanks for the tip. > > > > For the record, I found schedutils on Robert Love's page: > > > > http://rlove.org/ > > http://rlove.org/misc/schedutils-1.5.0.tar.gz > > > > However, I had already solved that part of the problem with a > > program of my own. > > > > My real problem is: the IRQ handlers for the I/O boards are > > only instantiated when the kernel module is inserted. How do > > I /reliably/ determine their pid? > > What about something like: > chrt -f -p 99 `/sbin/pidof 'IRQ 8'` If he knows that IRQ 8 is associated with his device, that is ok, but how to map device -> IRQ in the first place? > > > > e.g. on one system, the IRQ handler for my I/O board is IRQ5 > > with pid 745. On another system, it's IRQ20 with pid 808. > > On a third system they're IRQ20 and IRQ21 with pid 239 and 240. See? Perhaps he could use a kernel command line where he would tell that for the string used in request_irq the kthread priority should be N. IIRC there was somebody trying to write a patch to support this at some point in this list... - Arnaldo - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
