Whenever we see that a CPU is capable of C3 (during ACPI cstate init), we
disable local APIC timer and switch to using a broadcast from external timer
interrupt (IRQ 0).
Patch below adds the code for i386 and also the ACPI hunk.
Signed-off-by: Venkatesh Pallipadi <[email protected]>
Index: linux-2.6.15-rc3/arch/i386/kernel/time.c
===================================================================
--- linux-2.6.15-rc3.orig/arch/i386/kernel/time.c
+++ linux-2.6.15-rc3/arch/i386/kernel/time.c
@@ -302,6 +302,12 @@ irqreturn_t timer_interrupt(int irq, voi
do_timer_interrupt(irq, regs);
write_sequnlock(&xtime_lock);
+
+#ifdef CONFIG_X86_LOCAL_APIC
+ if (using_apic_timer)
+ smp_send_timer_broadcast_ipi(regs);
+#endif
+
return IRQ_HANDLED;
}
Index: linux-2.6.15-rc3/include/asm-i386/apic.h
===================================================================
--- linux-2.6.15-rc3.orig/include/asm-i386/apic.h
+++ linux-2.6.15-rc3/include/asm-i386/apic.h
@@ -132,6 +132,11 @@ extern unsigned int nmi_watchdog;
extern int disable_timer_pin_1;
+void smp_send_timer_broadcast_ipi(struct pt_regs *regs);
+void switch_APIC_timer_to_ipi(void *cpumask);
+void switch_ipi_to_APIC_timer(void *cpumask);
+#define ARCH_APICTIMER_STOPS_ON_C3 1
+
#else /* !CONFIG_X86_LOCAL_APIC */
static inline void lapic_shutdown(void) { }
Index: linux-2.6.15-rc3/arch/i386/kernel/apic.c
===================================================================
--- linux-2.6.15-rc3.orig/arch/i386/kernel/apic.c
+++ linux-2.6.15-rc3/arch/i386/kernel/apic.c
@@ -26,6 +26,7 @@
#include <linux/kernel_stat.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>
+#include <linux/module.h>
#include <asm/atomic.h>
#include <asm/smp.h>
@@ -37,10 +38,17 @@
#include <asm/i8253.h>
#include <mach_apic.h>
+#include <mach_ipi.h>
#include "io_ports.h"
/*
+ * cpu_mask that denotes the CPUs that needs timer interrupt coming in as
+ * IPIs in place of local APIC timers
+ */
+static cpumask_t timer_interrupt_broadcast_ipi_mask;
+
+/*
* Knob to control our willingness to enable the local APIC.
*/
int enable_local_apic __initdata = 0; /* -1=force-disable, +1=force-enable */
@@ -1068,7 +1076,7 @@ void __devinit setup_secondary_APIC_cloc
setup_APIC_timer(calibration_result);
}
-void __devinit disable_APIC_timer(void)
+void disable_APIC_timer(void)
{
if (using_apic_timer) {
unsigned long v;
@@ -1088,6 +1096,32 @@ void enable_APIC_timer(void)
}
}
+void switch_APIC_timer_to_ipi(void *cpumask)
+{
+ cpumask_t mask = *(cpumask_t *)cpumask;
+ int cpu = smp_processor_id();
+
+ if (cpu_isset(cpu, mask) &&
+ !cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) {
+ disable_APIC_timer();
+ cpu_set(cpu, timer_interrupt_broadcast_ipi_mask);
+ }
+}
+EXPORT_SYMBOL(switch_APIC_timer_to_ipi);
+
+void switch_ipi_to_APIC_timer(void *cpumask)
+{
+ cpumask_t mask = *(cpumask_t *)cpumask;
+ int cpu = smp_processor_id();
+
+ if (cpu_isset(cpu, mask) &&
+ cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) {
+ cpu_clear(cpu, timer_interrupt_broadcast_ipi_mask);
+ enable_APIC_timer();
+ }
+}
+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
+
#undef APIC_DIVISOR
/*
@@ -1152,6 +1186,36 @@ fastcall void smp_apic_timer_interrupt(s
irq_exit();
}
+#ifndef CONFIG_SMP
+static void up_apic_timer_interrupt_call(struct pt_regs *regs)
+{
+ int cpu = smp_processor_id();
+
+ /*
+ * the NMI deadlock-detector uses this.
+ */
+ per_cpu(irq_stat, cpu).apic_timer_irqs++;
+
+ smp_local_timer_interrupt(regs);
+}
+#endif
+
+void smp_send_timer_broadcast_ipi(struct pt_regs *regs)
+{
+ if (!cpus_empty(timer_interrupt_broadcast_ipi_mask)) {
+#ifdef CONFIG_SMP
+ send_IPI_mask(timer_interrupt_broadcast_ipi_mask,
+ LOCAL_TIMER_VECTOR);
+#else
+ /*
+ * We can directly call the apic timer interrupt handler
+ * in UP case. Minus all irq related functions
+ */
+ up_apic_timer_interrupt_call(regs);
+#endif
+ }
+}
+
int setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
Index: linux-2.6.15-rc3/drivers/acpi/processor_idle.c
===================================================================
--- linux-2.6.15-rc3.orig/drivers/acpi/processor_idle.c
+++ linux-2.6.15-rc3/drivers/acpi/processor_idle.c
@@ -929,6 +929,15 @@ static int acpi_processor_power_verify(s
unsigned int i;
unsigned int working = 0;
+#ifdef ARCH_APICTIMER_STOPS_ON_C3
+ struct cpuinfo_x86 *c = cpu_data + pr->id;
+ cpumask_t mask = cpumask_of_cpu(pr->id);
+
+ if (c->x86_vendor == X86_VENDOR_INTEL) {
+ on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
+ }
+#endif
+
for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
struct acpi_processor_cx *cx = &pr->power.states[i];
@@ -943,6 +952,12 @@ static int acpi_processor_power_verify(s
case ACPI_STATE_C3:
acpi_processor_power_verify_c3(pr, cx);
+#ifdef ARCH_APICTIMER_STOPS_ON_C3
+ if (c->x86_vendor == X86_VENDOR_INTEL) {
+ on_each_cpu(switch_APIC_timer_to_ipi,
+ &mask, 1, 1);
+ }
+#endif
break;
}
On Thu, 8 Dec 2005, Venkatesh Pallipadi wrote:
> Whenever we see that a CPU is capable of C3 (during ACPI cstate init), we
> disable local APIC timer and switch to using a broadcast from external timer
> interrupt (IRQ 0).
>
> Index: linux-2.6.15-rc3/include/asm-i386/apic.h
> ===================================================================
> --- linux-2.6.15-rc3.orig/include/asm-i386/apic.h
> +++ linux-2.6.15-rc3/include/asm-i386/apic.h
> @@ -132,6 +132,11 @@ extern unsigned int nmi_watchdog;
>
> extern int disable_timer_pin_1;
>
> +void smp_send_timer_broadcast_ipi(struct pt_regs *regs);
> +void switch_APIC_timer_to_ipi(void *cpumask);
> +void switch_ipi_to_APIC_timer(void *cpumask);
When is this used?
On Fri, Dec 09, 2005 at 12:06:35AM -0800, Zwane Mwaikambo wrote:
> On Thu, 8 Dec 2005, Venkatesh Pallipadi wrote:
>
> > Whenever we see that a CPU is capable of C3 (during ACPI cstate init), we
> > disable local APIC timer and switch to using a broadcast from external timer
> > interrupt (IRQ 0).
> >
> > +void smp_send_timer_broadcast_ipi(struct pt_regs *regs);
> > +void switch_APIC_timer_to_ipi(void *cpumask);
> > +void switch_ipi_to_APIC_timer(void *cpumask);
>
> When is this used?
+void smp_send_timer_broadcast_ipi(struct pt_regs *regs);
This is called by the IRQ0 timer interrupt handler, to check whether any CPUs
have enrolled for this broadcast.
+void switch_APIC_timer_to_ipi(void *cpumask);
Called by acpi processor driver when it find out that a particular CPU can
support C3 state (and it is an Intel CPU).
+void switch_ipi_to_APIC_timer(void *cpumask);
Called by acpi processor driver again to reset to APIC_timer when C3 is not
supported by the CPU.
The acpi processor driver calls can be at the boot time, or can be at run time
if BIOS enables/disables C3 at run time.
Thanks,
Venki
On Fri, 9 Dec 2005, Venkatesh Pallipadi wrote:
> On Fri, Dec 09, 2005 at 12:06:35AM -0800, Zwane Mwaikambo wrote:
> > On Thu, 8 Dec 2005, Venkatesh Pallipadi wrote:
> >
> > > Whenever we see that a CPU is capable of C3 (during ACPI cstate init), we
> > > disable local APIC timer and switch to using a broadcast from external timer
> > > interrupt (IRQ 0).
> > >
> > > +void smp_send_timer_broadcast_ipi(struct pt_regs *regs);
> > > +void switch_APIC_timer_to_ipi(void *cpumask);
> > > +void switch_ipi_to_APIC_timer(void *cpumask);
> >
> > When is this used?
>
> +void smp_send_timer_broadcast_ipi(struct pt_regs *regs);
> This is called by the IRQ0 timer interrupt handler, to check whether any CPUs
> have enrolled for this broadcast.
>
> +void switch_APIC_timer_to_ipi(void *cpumask);
> Called by acpi processor driver when it find out that a particular CPU can
> support C3 state (and it is an Intel CPU).
>
> +void switch_ipi_to_APIC_timer(void *cpumask);
> Called by acpi processor driver again to reset to APIC_timer when C3 is not
> supported by the CPU.
Well i was more curious as to where in the patchset the
switch_ipi_to_APIC_timer is used;
zwane@montezuma linux-2.6-hg-x86_64 {0:1} grep switch_ipi_to_APIC_timer /tmp/patch[1234]
/tmp/patch2:+void switch_ipi_to_APIC_timer(void *cpumask);
/tmp/patch2:+void switch_ipi_to_APIC_timer(void *cpumask)
/tmp/patch2:+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
/tmp/patch4:+void switch_ipi_to_APIC_timer(void *cpumask)
/tmp/patch4:+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
/tmp/patch4:+void switch_ipi_to_APIC_timer(void *cpumask);
Or will it only be used in future?
>
> zwane@montezuma linux-2.6-hg-x86_64 {0:1} grep switch_ipi_to_APIC_timer /tmp/patch[1234]
> /tmp/patch2:+void switch_ipi_to_APIC_timer(void *cpumask);
> /tmp/patch2:+void switch_ipi_to_APIC_timer(void *cpumask)
> /tmp/patch2:+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
> /tmp/patch4:+void switch_ipi_to_APIC_timer(void *cpumask)
> /tmp/patch4:+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
> /tmp/patch4:+void switch_ipi_to_APIC_timer(void *cpumask);
>
> Or will it only be used in future?
It should be used in drivers/acpi/processor_* before enabling C3.
Or at least it was that way in some earlier patches Venki sent
around.
-Andi
On Fri, Dec 09, 2005 at 09:35:36AM -0800, Zwane Mwaikambo wrote:
> > +void switch_ipi_to_APIC_timer(void *cpumask);
> > Called by acpi processor driver again to reset to APIC_timer when C3 is not
> > supported by the CPU.
>
> Well i was more curious as to where in the patchset the
> switch_ipi_to_APIC_timer is used;
>
> zwane@montezuma linux-2.6-hg-x86_64 {0:1} grep switch_ipi_to_APIC_timer /tmp/patch[1234]
> /tmp/patch2:+void switch_ipi_to_APIC_timer(void *cpumask);
> /tmp/patch2:+void switch_ipi_to_APIC_timer(void *cpumask)
> /tmp/patch2:+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
> /tmp/patch4:+void switch_ipi_to_APIC_timer(void *cpumask)
> /tmp/patch4:+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
> /tmp/patch4:+void switch_ipi_to_APIC_timer(void *cpumask);
>
> Or will it only be used in future?
>
That calls for updated patch 2/3 (That was a typo on my original patch :()
Both switch_ipi_to_APIC_timer and switch_APIC_timer_to_ipi are called in
acpi/processor_idle.c in this patch.
--
Whenever we see that a CPU is capable of C3 (during ACPI cstate init), we
disable local APIC timer and switch to using a broadcast from external timer
interrupt (IRQ 0).
Patch below adds the code for i386 and also the ACPI hunk.
Signed-off-by: Venkatesh Pallipadi <[email protected]>
Index: linux-2.6.15-rc3/arch/i386/kernel/time.c
===================================================================
--- linux-2.6.15-rc3.orig/arch/i386/kernel/time.c
+++ linux-2.6.15-rc3/arch/i386/kernel/time.c
@@ -302,6 +302,12 @@ irqreturn_t timer_interrupt(int irq, voi
do_timer_interrupt(irq, regs);
write_sequnlock(&xtime_lock);
+
+#ifdef CONFIG_X86_LOCAL_APIC
+ if (using_apic_timer)
+ smp_send_timer_broadcast_ipi(regs);
+#endif
+
return IRQ_HANDLED;
}
Index: linux-2.6.15-rc3/include/asm-i386/apic.h
===================================================================
--- linux-2.6.15-rc3.orig/include/asm-i386/apic.h
+++ linux-2.6.15-rc3/include/asm-i386/apic.h
@@ -132,6 +132,11 @@ extern unsigned int nmi_watchdog;
extern int disable_timer_pin_1;
+void smp_send_timer_broadcast_ipi(struct pt_regs *regs);
+void switch_APIC_timer_to_ipi(void *cpumask);
+void switch_ipi_to_APIC_timer(void *cpumask);
+#define ARCH_APICTIMER_STOPS_ON_C3 1
+
#else /* !CONFIG_X86_LOCAL_APIC */
static inline void lapic_shutdown(void) { }
Index: linux-2.6.15-rc3/arch/i386/kernel/apic.c
===================================================================
--- linux-2.6.15-rc3.orig/arch/i386/kernel/apic.c
+++ linux-2.6.15-rc3/arch/i386/kernel/apic.c
@@ -26,6 +26,7 @@
#include <linux/kernel_stat.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>
+#include <linux/module.h>
#include <asm/atomic.h>
#include <asm/smp.h>
@@ -37,10 +38,17 @@
#include <asm/i8253.h>
#include <mach_apic.h>
+#include <mach_ipi.h>
#include "io_ports.h"
/*
+ * cpu_mask that denotes the CPUs that needs timer interrupt coming in as
+ * IPIs in place of local APIC timers
+ */
+static cpumask_t timer_interrupt_broadcast_ipi_mask;
+
+/*
* Knob to control our willingness to enable the local APIC.
*/
int enable_local_apic __initdata = 0; /* -1=force-disable, +1=force-enable */
@@ -1068,7 +1076,7 @@ void __devinit setup_secondary_APIC_cloc
setup_APIC_timer(calibration_result);
}
-void __devinit disable_APIC_timer(void)
+void disable_APIC_timer(void)
{
if (using_apic_timer) {
unsigned long v;
@@ -1088,6 +1096,32 @@ void enable_APIC_timer(void)
}
}
+void switch_APIC_timer_to_ipi(void *cpumask)
+{
+ cpumask_t mask = *(cpumask_t *)cpumask;
+ int cpu = smp_processor_id();
+
+ if (cpu_isset(cpu, mask) &&
+ !cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) {
+ disable_APIC_timer();
+ cpu_set(cpu, timer_interrupt_broadcast_ipi_mask);
+ }
+}
+EXPORT_SYMBOL(switch_APIC_timer_to_ipi);
+
+void switch_ipi_to_APIC_timer(void *cpumask)
+{
+ cpumask_t mask = *(cpumask_t *)cpumask;
+ int cpu = smp_processor_id();
+
+ if (cpu_isset(cpu, mask) &&
+ cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) {
+ cpu_clear(cpu, timer_interrupt_broadcast_ipi_mask);
+ enable_APIC_timer();
+ }
+}
+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
+
#undef APIC_DIVISOR
/*
@@ -1152,6 +1186,36 @@ fastcall void smp_apic_timer_interrupt(s
irq_exit();
}
+#ifndef CONFIG_SMP
+static void up_apic_timer_interrupt_call(struct pt_regs *regs)
+{
+ int cpu = smp_processor_id();
+
+ /*
+ * the NMI deadlock-detector uses this.
+ */
+ per_cpu(irq_stat, cpu).apic_timer_irqs++;
+
+ smp_local_timer_interrupt(regs);
+}
+#endif
+
+void smp_send_timer_broadcast_ipi(struct pt_regs *regs)
+{
+ if (!cpus_empty(timer_interrupt_broadcast_ipi_mask)) {
+#ifdef CONFIG_SMP
+ send_IPI_mask(timer_interrupt_broadcast_ipi_mask,
+ LOCAL_TIMER_VECTOR);
+#else
+ /*
+ * We can directly call the apic timer interrupt handler
+ * in UP case. Minus all irq related functions
+ */
+ up_apic_timer_interrupt_call(regs);
+#endif
+ }
+}
+
int setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
Index: linux-2.6.15-rc3/drivers/acpi/processor_idle.c
===================================================================
--- linux-2.6.15-rc3.orig/drivers/acpi/processor_idle.c
+++ linux-2.6.15-rc3/drivers/acpi/processor_idle.c
@@ -929,6 +929,15 @@ static int acpi_processor_power_verify(s
unsigned int i;
unsigned int working = 0;
+#ifdef ARCH_APICTIMER_STOPS_ON_C3
+ struct cpuinfo_x86 *c = cpu_data + pr->id;
+ cpumask_t mask = cpumask_of_cpu(pr->id);
+
+ if (c->x86_vendor == X86_VENDOR_INTEL) {
+ on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
+ }
+#endif
+
for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
struct acpi_processor_cx *cx = &pr->power.states[i];
@@ -943,6 +952,12 @@ static int acpi_processor_power_verify(s
case ACPI_STATE_C3:
acpi_processor_power_verify_c3(pr, cx);
+#ifdef ARCH_APICTIMER_STOPS_ON_C3
+ if (c->x86_vendor == X86_VENDOR_INTEL) {
+ on_each_cpu(switch_APIC_timer_to_ipi,
+ &mask, 1, 1);
+ }
+#endif
break;
}
Just a quick comment - didn't review the full patch.
> +#ifdef ARCH_APICTIMER_STOPS_ON_C3
> + if (c->x86_vendor == X86_VENDOR_INTEL) {
> + on_each_cpu(switch_APIC_timer_to_ipi,
> + &mask, 1, 1);
> + }
> +#endif
Better make it a runtime variable instead of an ifdef with a boot option.
I found at least one non Intel system so far with the same issue
(although it wasn't multi processor)
-Andi
On Fri, 9 Dec 2005, Venkatesh Pallipadi wrote:
> On Fri, Dec 09, 2005 at 09:35:36AM -0800, Zwane Mwaikambo wrote:
> > > +void switch_ipi_to_APIC_timer(void *cpumask);
> > > Called by acpi processor driver again to reset to APIC_timer when C3 is not
> > > supported by the CPU.
> >
> > Well i was more curious as to where in the patchset the
> > switch_ipi_to_APIC_timer is used;
> >
> > zwane@montezuma linux-2.6-hg-x86_64 {0:1} grep switch_ipi_to_APIC_timer /tmp/patch[1234]
> > /tmp/patch2:+void switch_ipi_to_APIC_timer(void *cpumask);
> > /tmp/patch2:+void switch_ipi_to_APIC_timer(void *cpumask)
> > /tmp/patch2:+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
> > /tmp/patch4:+void switch_ipi_to_APIC_timer(void *cpumask)
> > /tmp/patch4:+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
> > /tmp/patch4:+void switch_ipi_to_APIC_timer(void *cpumask);
> >
> > Or will it only be used in future?
> >
>
> That calls for updated patch 2/3 (That was a typo on my original patch :()
Thanks Venki, i'll have a look at the rest too.
On Fri, Dec 09, 2005 at 07:07:39PM +0100, Andi Kleen wrote:
> Just a quick comment - didn't review the full patch.
>
> > +#ifdef ARCH_APICTIMER_STOPS_ON_C3
> > + if (c->x86_vendor == X86_VENDOR_INTEL) {
> > + on_each_cpu(switch_APIC_timer_to_ipi,
> > + &mask, 1, 1);
> > + }
> > +#endif
>
> Better make it a runtime variable instead of an ifdef with a boot option.
> I found at least one non Intel system so far with the same issue
> (although it wasn't multi processor)
Actually, that particular ifdef ARCH_APICTIMER_STOPS_ON_C3 is always set for
i386 and x86-64 and local APIC is enabled. I only added that ifdef to skip
this code for IA-64, which can also use acpi processor_idle.c.
For any other CPU in i386 or x86-64, we can just add runtime check along with
VENDOR_INTEL.
Thanks,
Venki
I am sending an updated patchset.
(The original patchset
http://www.ussg.iu.edu/hypermail/linux/kernel/0512.1/0300.html)
The fixes in the updated patchset
- Typo with ipi_to_APIC_timer call fixed
- The issues with suspend-resume (offline-online) handled.
Thanks,
Venki
On Mon, Dec 12, 2005 at 05:47:20PM -0800, Pallipadi, Venkatesh wrote:
>
> I am sending an updated patchset.
>
> (The original patchset
> http://www.ussg.iu.edu/hypermail/linux/kernel/0512.1/0300.html)
>
> The fixes in the updated patchset
> - Typo with ipi_to_APIC_timer call fixed
> - The issues with suspend-resume (offline-online) handled.
Looks all good. I will merge it up into my tree thanks.
Ok your globals are too long :)
-Andi