Hello Bjorn,
Sorry for the delay in my reponse.
> > From: Björn Steinbrink <[email protected]>
> >
> > Separate the performance counter reservation system from the nmi
> > watchdog to allow usage of all performance counters even if the nmi
> > watchdog is not used.
> >
I think it is a good idea to separate the counter allocator from NMI
becuase as you said they are/will be use used by more than the NMI
watchdog. Thus, I think you should drop the stirng nmi from the
routines. I would also povide a separate header file for this allocator.
> > Fixed the reservation of the wrong performance counter for the PerfMon
> > based nmi watchdog along the way.
> >
> > Signed-off-by: Björn Steinbrink <[email protected]>
> > ---
> > diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
> > index 67824f3..88b74e3 100644
> > --- a/arch/i386/kernel/apic.c
> > +++ b/arch/i386/kernel/apic.c
> > @@ -1009,6 +1009,7 @@ void __devinit setup_local_APIC(void)
> > value |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
> > apic_write_around(APIC_LVTT, value);
> >
> > + probe_performance_counters();
> > setup_apic_nmi_watchdog(NULL);
> > apic_pm_activate();
> > }
> > diff --git a/arch/i386/kernel/cpu/Makefile b/arch/i386/kernel/cpu/Makefile
> > index 74f27a4..882364d 100644
> > --- a/arch/i386/kernel/cpu/Makefile
> > +++ b/arch/i386/kernel/cpu/Makefile
> > @@ -18,4 +18,4 @@ obj-$(CONFIG_X86_MCE) += mcheck/
> > obj-$(CONFIG_MTRR) += mtrr/
> > obj-$(CONFIG_CPU_FREQ) += cpufreq/
> >
> > -obj-$(CONFIG_X86_LOCAL_APIC) += perfctr-watchdog.o
> > +obj-$(CONFIG_X86_LOCAL_APIC) += perfctr.o perfctr-watchdog.o
> > diff --git a/arch/i386/kernel/cpu/perfctr-watchdog.c b/arch/i386/kernel/cpu/perfctr-watchdog.c
> > index 2b04c8f..6187097 100644
> > --- a/arch/i386/kernel/cpu/perfctr-watchdog.c
> > +++ b/arch/i386/kernel/cpu/perfctr-watchdog.c
> > @@ -8,9 +8,7 @@
> > Original code for K7/P6 written by Keith Owens */
> >
> > #include <linux/percpu.h>
> > -#include <linux/module.h>
> > #include <linux/kernel.h>
> > -#include <linux/bitops.h>
> > #include <linux/smp.h>
> > #include <linux/nmi.h>
> > #include <asm/apic.h>
> > @@ -36,105 +34,8 @@ struct wd_ops {
> >
> > static struct wd_ops *wd_ops;
> >
> > -/* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
> > - * offset from MSR_P4_BSU_ESCR0. It will be the max for all platforms (for now)
> > - */
> > -#define NMI_MAX_COUNTER_BITS 66
> > -
> > -/* perfctr_nmi_owner tracks the ownership of the perfctr registers:
> > - * evtsel_nmi_owner tracks the ownership of the event selection
> > - * - different performance counters/ event selection may be reserved for
> > - * different subsystems this reservation system just tries to coordinate
> > - * things a little
> > - */
> > -static DECLARE_BITMAP(perfctr_nmi_owner, NMI_MAX_COUNTER_BITS);
> > -static DECLARE_BITMAP(evntsel_nmi_owner, NMI_MAX_COUNTER_BITS);
> > -
> > static DEFINE_PER_CPU(struct nmi_watchdog_ctlblk, nmi_watchdog_ctlblk);
> >
> > -/* converts an msr to an appropriate reservation bit */
> > -static inline unsigned int nmi_perfctr_msr_to_bit(unsigned int msr)
> > -{
> > - return wd_ops ? msr - wd_ops->perfctr : 0;
> > -}
> > -
> > -/* converts an msr to an appropriate reservation bit */
> > -/* returns the bit offset of the event selection register */
> > -static inline unsigned int nmi_evntsel_msr_to_bit(unsigned int msr)
> > -{
> > - return wd_ops ? msr - wd_ops->evntsel : 0;
> > -}
> > -
> > -/* checks for a bit availability (hack for oprofile) */
> > -int avail_to_resrv_perfctr_nmi_bit(unsigned int counter)
> > -{
> > - BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > -
> > - return (!test_bit(counter, perfctr_nmi_owner));
> > -}
> > -
> > -/* checks the an msr for availability */
> > -int avail_to_resrv_perfctr_nmi(unsigned int msr)
> > -{
> > - unsigned int counter;
> > -
> > - counter = nmi_perfctr_msr_to_bit(msr);
> > - BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > -
> > - return (!test_bit(counter, perfctr_nmi_owner));
> > -}
> > -
> > -int reserve_perfctr_nmi(unsigned int msr)
> > -{
> > - unsigned int counter;
> > -
> > - counter = nmi_perfctr_msr_to_bit(msr);
> > - BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > -
> > - if (!test_and_set_bit(counter, perfctr_nmi_owner))
> > - return 1;
> > - return 0;
> > -}
> > -
> > -void release_perfctr_nmi(unsigned int msr)
> > -{
> > - unsigned int counter;
> > -
> > - counter = nmi_perfctr_msr_to_bit(msr);
> > - BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > -
> > - clear_bit(counter, perfctr_nmi_owner);
> > -}
> > -
> > -int reserve_evntsel_nmi(unsigned int msr)
> > -{
> > - unsigned int counter;
> > -
> > - counter = nmi_evntsel_msr_to_bit(msr);
> > - BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > -
> > - if (!test_and_set_bit(counter, evntsel_nmi_owner))
> > - return 1;
> > - return 0;
> > -}
> > -
> > -void release_evntsel_nmi(unsigned int msr)
> > -{
> > - unsigned int counter;
> > -
> > - counter = nmi_evntsel_msr_to_bit(msr);
> > - BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > -
> > - clear_bit(counter, evntsel_nmi_owner);
> > -}
> > -
> > -EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi);
> > -EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi_bit);
> > -EXPORT_SYMBOL(reserve_perfctr_nmi);
> > -EXPORT_SYMBOL(release_perfctr_nmi);
> > -EXPORT_SYMBOL(reserve_evntsel_nmi);
> > -EXPORT_SYMBOL(release_evntsel_nmi);
> > -
> > void disable_lapic_nmi_watchdog(void)
> > {
> > BUG_ON(nmi_watchdog != NMI_LOCAL_APIC);
> > @@ -568,8 +469,8 @@ static struct wd_ops intel_arch_wd_ops = {
> > .setup = setup_intel_arch_watchdog,
> > .rearm = p6_rearm,
> > .stop = single_msr_stop_watchdog,
> > - .perfctr = MSR_ARCH_PERFMON_PERFCTR0,
> > - .evntsel = MSR_ARCH_PERFMON_EVENTSEL0,
> > + .perfctr = MSR_ARCH_PERFMON_PERFCTR1,
> > + .evntsel = MSR_ARCH_PERFMON_EVENTSEL1,
> > };
> >
> > static void probe_nmi_watchdog(void)
> > diff --git a/arch/i386/kernel/cpu/perfctr.c b/arch/i386/kernel/cpu/perfctr.c
> > new file mode 100644
> > index 0000000..63e68a3
> > --- /dev/null
> > +++ b/arch/i386/kernel/cpu/perfctr.c
> > @@ -0,0 +1,175 @@
> > +#include <linux/bitops.h>
> > +#include <linux/module.h>
> > +#include <asm/msr-index.h>
> > +#include <asm/intel_arch_perfmon.h>
> > +
> > +struct perfctr_base_regs {
> > + unsigned int perfctr;
> > + unsigned int evntsel;
> > +};
> > +
> > +static struct perfctr_base_regs *perfctr_base_regs;
> > +
> > +static struct perfctr_base_regs k7_base_regs = {
> > + .perfctr = MSR_K7_PERFCTR0,
> > + .evntsel = MSR_K7_EVNTSEL0
> > +};
> > +
> > +static struct perfctr_base_regs p4_base_regs = {
> > + .perfctr = MSR_P4_BPU_PERFCTR0,
> > + .evntsel = MSR_P4_BSU_ESCR0
> > +};
> > +
> > +static struct perfctr_base_regs p6_base_regs = {
> > + .perfctr = MSR_P6_PERFCTR0,
> > + .evntsel = MSR_P6_EVNTSEL0
> > +};
> > +
> > +static struct perfctr_base_regs arch_perfmon_base_regs = {
> > + .perfctr = MSR_ARCH_PERFMON_PERFCTR0,
> > + .evntsel = MSR_ARCH_PERFMON_EVENTSEL0
> > +};
> > +
> > +/* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
> > + * offset from MSR_P4_BSU_ESCR0. It will be the max for all platforms (for now)
> > + */
> > +#define NMI_MAX_COUNTER_BITS 66
> > +
> > +/* perfctr_nmi_owner tracks the ownership of the perfctr registers:
> > + * evtsel_nmi_owner tracks the ownership of the event selection
> > + * - different performance counters/ event selection may be reserved for
> > + * different subsystems this reservation system just tries to coordinate
> > + * things a little
> > + */
> > +static DECLARE_BITMAP(perfctr_nmi_owner, NMI_MAX_COUNTER_BITS);
> > +static DECLARE_BITMAP(evntsel_nmi_owner, NMI_MAX_COUNTER_BITS);
> > +
> > +void __devinit probe_performance_counters(void)
> > +{
> > + switch (boot_cpu_data.x86_vendor) {
> > + case X86_VENDOR_AMD:
> > + if (boot_cpu_data.x86 != 6 && boot_cpu_data.x86 != 15 &&
> > + boot_cpu_data.x86 != 16)
> > + return;
> > +
> > + perfctr_base_regs = &k7_base_regs;
> > + break;
> > +
> > + case X86_VENDOR_INTEL:
> > + if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) {
> > + perfctr_base_regs = &arch_perfmon_base_regs;
> > + break;
> > + }
> > + switch (boot_cpu_data.x86) {
> > + case 6:
> > + perfctr_base_regs = &p6_base_regs;
> > + break;
> > +
> > + case 15:
> > + perfctr_base_regs = &p4_base_regs;
> > + break;
> > + }
> > + break;
> > + }
> > +}
> > +
> > +/* converts an msr to an appropriate reservation bit */
> > +static inline unsigned int nmi_perfctr_msr_to_bit(unsigned int msr)
> > +{
> > + return msr - perfctr_base_regs->perfctr;
> > +}
> > +
> > +/* converts an msr to an appropriate reservation bit */
> > +/* returns the bit offset of the event selection register */
> > +static inline unsigned int nmi_evntsel_msr_to_bit(unsigned int msr)
> > +{
> > + return msr - perfctr_base_regs->evntsel;
> > +}
> > +
> > +/* checks for a bit availability (hack for oprofile) */
> > +int avail_to_resrv_perfctr_nmi_bit(unsigned int counter)
> > +{
> > + if (!perfctr_base_regs)
> > + return 0;
> > +
> > + BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > +
> > + return (!test_bit(counter, perfctr_nmi_owner));
> > +}
> > +
> > +/* checks the an msr for availability */
> > +int avail_to_resrv_perfctr_nmi(unsigned int msr)
> > +{
> > + unsigned int counter;
> > +
> > + if (!perfctr_base_regs)
> > + return 0;
> > +
> > + counter = nmi_perfctr_msr_to_bit(msr);
> > + BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > +
> > + return (!test_bit(counter, perfctr_nmi_owner));
> > +}
> > +
> > +int reserve_perfctr_nmi(unsigned int msr)
> > +{
> > + unsigned int counter;
> > +
> > + if (!perfctr_base_regs)
> > + return 0;
> > +
> > + counter = nmi_perfctr_msr_to_bit(msr);
> > + BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > +
> > + if (!test_and_set_bit(counter, perfctr_nmi_owner))
> > + return 1;
> > + return 0;
> > +}
> > +
> > +void release_perfctr_nmi(unsigned int msr)
> > +{
> > + unsigned int counter;
> > +
> > + if (!perfctr_base_regs)
> > + return 0;
> > +
> > + counter = nmi_perfctr_msr_to_bit(msr);
> > + BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > +
> > + clear_bit(counter, perfctr_nmi_owner);
> > +}
> > +
> > +int reserve_evntsel_nmi(unsigned int msr)
> > +{
> > + unsigned int counter;
> > +
> > + if (!perfctr_base_regs)
> > + return 0;
> > +
> > + counter = nmi_evntsel_msr_to_bit(msr);
> > + BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > +
> > + if (!test_and_set_bit(counter, evntsel_nmi_owner))
> > + return 1;
> > + return 0;
> > +}
> > +
> > +void release_evntsel_nmi(unsigned int msr)
> > +{
> > + unsigned int counter;
> > +
> > + if (!perfctr_base_regs)
> > + return 0;
> > +
> > + counter = nmi_evntsel_msr_to_bit(msr);
> > + BUG_ON(counter > NMI_MAX_COUNTER_BITS);
> > +
> > + clear_bit(counter, evntsel_nmi_owner);
> > +}
> > +
> > +EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi);
> > +EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi_bit);
> > +EXPORT_SYMBOL(reserve_perfctr_nmi);
> > +EXPORT_SYMBOL(release_perfctr_nmi);
> > +EXPORT_SYMBOL(reserve_evntsel_nmi);
> > +EXPORT_SYMBOL(release_evntsel_nmi);
> > diff --git a/arch/x86_64/kernel/Makefile b/arch/x86_64/kernel/Makefile
> > index de1de8a..cc7587d 100644
> > --- a/arch/x86_64/kernel/Makefile
> > +++ b/arch/x86_64/kernel/Makefile
> > @@ -9,7 +9,7 @@ obj-y := process.o signal.o entry.o traps.o irq.o \
> > x8664_ksyms.o i387.o syscall.o vsyscall.o \
> > setup64.o bootflag.o e820.o reboot.o quirks.o i8237.o \
> > pci-dma.o pci-nommu.o alternative.o hpet.o tsc.o bugs.o \
> > - perfctr-watchdog.o
> > + perfctr.o perfctr-watchdog.o
> >
> > obj-$(CONFIG_STACKTRACE) += stacktrace.o
> > obj-$(CONFIG_X86_MCE) += mce.o therm_throt.o
> > @@ -60,4 +60,5 @@ i8237-y += ../../i386/kernel/i8237.o
> > msr-$(subst m,y,$(CONFIG_X86_MSR)) += ../../i386/kernel/msr.o
> > alternative-y += ../../i386/kernel/alternative.o
> > pcspeaker-y += ../../i386/kernel/pcspeaker.o
> > +perfctr-y += ../../i386/kernel/cpu/perfctr.o
> > perfctr-watchdog-y += ../../i386/kernel/cpu/perfctr-watchdog.o
> > diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
> > index 1b0e07b..892ebf8 100644
> > --- a/arch/x86_64/kernel/apic.c
> > +++ b/arch/x86_64/kernel/apic.c
> > @@ -453,6 +453,7 @@ void __cpuinit setup_local_APIC (void)
> > oldvalue, value);
> > }
> >
> > + probe_performance_counters();
> > nmi_watchdog_default();
> > setup_apic_nmi_watchdog(NULL);
> > apic_pm_activate();
> > diff --git a/include/asm-i386/nmi.h b/include/asm-i386/nmi.h
> > index fb1e133..736af6f 100644
> > --- a/include/asm-i386/nmi.h
> > +++ b/include/asm-i386/nmi.h
> > @@ -18,6 +18,7 @@
> > int do_nmi_callback(struct pt_regs *regs, int cpu);
> >
> > extern int nmi_watchdog_enabled;
> > +extern void probe_performance_counters(void);
> > extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
> > extern int avail_to_resrv_perfctr_nmi(unsigned int);
> > extern int reserve_perfctr_nmi(unsigned int);
> > diff --git a/include/asm-x86_64/nmi.h b/include/asm-x86_64/nmi.h
> > index d0a7f53..d45fc62 100644
> > --- a/include/asm-x86_64/nmi.h
> > +++ b/include/asm-x86_64/nmi.h
> > @@ -46,6 +46,7 @@ extern int unknown_nmi_panic;
> > extern int nmi_watchdog_enabled;
> >
> > extern int check_nmi_watchdog(void);
> > +extern void probe_performance_counters(void);
> > extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
> > extern int avail_to_resrv_perfctr_nmi(unsigned int);
> > extern int reserve_perfctr_nmi(unsigned int);
> > -
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> > Please read the FAQ at http://www.tux.org/lkml/
--
-Stephane
-
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