cvs commit: src/sys/i386/i386 apic_vector.s local_apic.c mp_machdep.c src/sys/i386/include apicvar.h smp.h src/sys/i386/isa clock.c

[John Baldwin]

jhb         2005-02-08 20:25:07 UTC

  FreeBSD src repository

  Modified files:
    sys/i386/i386        apic_vector.s local_apic.c mp_machdep.c 
    sys/i386/include     apicvar.h smp.h 
    sys/i386/isa         clock.c 
  Log:
  Use the local APIC timer to drive the various kernel clocks on SMP machines
  rather than forwarding interrupts from the clock devices around using IPIs:
  - Add an IDT vector that pushes a clock frame and calls
    lapic_handle_timer().
  - Add functions to program the local APIC timer including setting the
    divisor, and setting up the timer to either down a periodic countdown
    or one-shot countdown.
  - Add a lapic_setup_clock() function that the BSP calls from
    cpu_init_clocks() to setup the local APIC timer if it is going to be
    used.  The setup uses a one-shot countdown to calibrate the timer.  We
    then program the timer on each CPU to fire at a frequency of hz * 3.
    stathz is defined as freq / 23 (hz * 3 / 23), and profhz is defined as
    freq / 2 (hz * 3 / 2).  This gives the clocks relatively prime divisors
    while keeping a low LCM for the frequency of the clock interrupts.
    Thanks to Peter Jeremy for suggesting this approach.
  - Remove the hardclock and statclock forwarding code including the two
    associated IPIs.  The bitmap IPI handler has now effectively degenerated
    to just IPI_AST.
  - When the local APIC timer is used we don't turn the RTC on at all, but
    we still enable interrupts on the ISA timer 0 (i8254) for timecounting
    purposes.
  
  Revision  Changes    Path
  1.103     +24 -0     src/sys/i386/i386/apic_vector.s
  1.13      +186 -2    src/sys/i386/i386/local_apic.c
  1.244     +0 -67     src/sys/i386/i386/mp_machdep.c
  1.11      +4 -4      src/sys/i386/include/apicvar.h
  1.81      +0 -2      src/sys/i386/include/smp.h
  1.215     +19 -19    src/sys/i386/isa/clock.c