On Sat, Sep 10, 2005 at 09:34:48PM +0200, Zlatan Ibrahimovic wrote: > Hi folks, > I've seen clock software interrupt thread (referring to clk_ithd in > kern/kern_intr.c); watching to manpages I read that priority is used > as vector for that thread. My question is how can I call this software > handler? There's no track in the IDT for the associated handler... > (ia32, for better check see i386/i386/exception.s).
The softclock() function is registered as an another one handler for SWI_CLOCK by calling the swi_add() function. Since clk_ithd is NULL at the moment when swi_add() for softclock() handler is called, interrupt thread is created for SWI_CLOCK in swi_addr() by the ithread_create() function. An interrupt thread is a special kthread and interrupt threads run ithread_loop() function as the main function for kthread. Interrupt handler for the softclock() function is returned in softclock_ih. The simplified idea of ithread_loop() is the following: if there is the request for some handler, then process this request by requested handler else voluntary switch context. Another one handler for SWI_CLOCK is siopoll(). If you run "ps auxw | grep clock" you will see two handlers for swi5 (SWI_CLOCK). When hardclock() decides that softclock() should be called is schedules clk_ithd ithread via handler softclock_ih by calling swi_sched(). _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
