Date: Tue, 8 Feb 2005 20:25:07 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: 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 Message-ID: <200502082025.j18KP72E069507@repoman.freebsd.org>
next in thread | raw e-mail | index | archive | help
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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200502082025.j18KP72E069507>