diff options
| -rw-r--r-- | arch/i386/kernel/paravirt.c | 2 | ||||
| -rw-r--r-- | arch/i386/kernel/tsc.c | 23 | ||||
| -rw-r--r-- | arch/i386/kernel/vmi.c | 2 | ||||
| -rw-r--r-- | arch/i386/kernel/vmiclock.c | 6 | ||||
| -rw-r--r-- | include/asm-i386/paravirt.h | 7 | ||||
| -rw-r--r-- | include/asm-i386/timer.h | 32 | ||||
| -rw-r--r-- | include/asm-i386/vmi_time.h | 2 |
7 files changed, 57 insertions, 17 deletions
diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c index 60e08b9..53f07a8 100644 --- a/arch/i386/kernel/paravirt.c +++ b/arch/i386/kernel/paravirt.c @@ -302,7 +302,7 @@ struct paravirt_ops paravirt_ops = { .write_msr = native_write_msr_safe, .read_tsc = native_read_tsc, .read_pmc = native_read_pmc, - .get_scheduled_cycles = native_read_tsc, + .sched_clock = native_sched_clock, .get_cpu_khz = native_calculate_cpu_khz, .load_tr_desc = native_load_tr_desc, .set_ldt = native_set_ldt, diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c index ea63a30..252f901 100644 --- a/arch/i386/kernel/tsc.c +++ b/arch/i386/kernel/tsc.c @@ -84,7 +84,7 @@ static inline int check_tsc_unstable(void) * * -johnstul@us.ibm.com "math is hard, lets go shopping!" */ -static unsigned long cyc2ns_scale __read_mostly; +unsigned long cyc2ns_scale __read_mostly; #define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ @@ -93,15 +93,10 @@ static inline void set_cyc2ns_scale(unsigned long cpu_khz) cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz; } -static inline unsigned long long cycles_2_ns(unsigned long long cyc) -{ - return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR; -} - /* * Scheduler clock - returns current time in nanosec units. */ -unsigned long long sched_clock(void) +unsigned long long native_sched_clock(void) { unsigned long long this_offset; @@ -118,12 +113,24 @@ unsigned long long sched_clock(void) return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ); /* read the Time Stamp Counter: */ - get_scheduled_cycles(this_offset); + rdtscll(this_offset); /* return the value in ns */ return cycles_2_ns(this_offset); } +/* We need to define a real function for sched_clock, to override the + weak default version */ +#ifdef CONFIG_PARAVIRT +unsigned long long sched_clock(void) +{ + return paravirt_sched_clock(); +} +#else +unsigned long long sched_clock(void) + __attribute__((alias("native_sched_clock"))); +#endif + unsigned long native_calculate_cpu_khz(void) { unsigned long long start, end; diff --git a/arch/i386/kernel/vmi.c b/arch/i386/kernel/vmi.c index 234bd6f..72042bb 100644 --- a/arch/i386/kernel/vmi.c +++ b/arch/i386/kernel/vmi.c @@ -891,7 +891,7 @@ static inline int __init activate_vmi(void) paravirt_ops.setup_boot_clock = vmi_time_bsp_init; paravirt_ops.setup_secondary_clock = vmi_time_ap_init; #endif - paravirt_ops.get_scheduled_cycles = vmi_get_sched_cycles; + paravirt_ops.sched_clock = vmi_sched_clock; paravirt_ops.get_cpu_khz = vmi_cpu_khz; /* We have true wallclock functions; disable CMOS clock sync */ diff --git a/arch/i386/kernel/vmiclock.c b/arch/i386/kernel/vmiclock.c index 26a37f8..f9b845f 100644 --- a/arch/i386/kernel/vmiclock.c +++ b/arch/i386/kernel/vmiclock.c @@ -64,10 +64,10 @@ int vmi_set_wallclock(unsigned long now) return 0; } -/* paravirt_ops.get_scheduled_cycles = vmi_get_sched_cycles */ -unsigned long long vmi_get_sched_cycles(void) +/* paravirt_ops.sched_clock = vmi_sched_clock */ +unsigned long long vmi_sched_clock(void) { - return vmi_timer_ops.get_cycle_counter(VMI_CYCLES_AVAILABLE); + return cycles_2_ns(vmi_timer_ops.get_cycle_counter(VMI_CYCLES_AVAILABLE)); } /* paravirt_ops.get_cpu_khz = vmi_cpu_khz */ diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h index 690ada2..7df88be 100644 --- a/include/asm-i386/paravirt.h +++ b/include/asm-i386/paravirt.h @@ -118,7 +118,7 @@ struct paravirt_ops u64 (*read_tsc)(void); u64 (*read_pmc)(void); - u64 (*get_scheduled_cycles)(void); + unsigned long long (*sched_clock)(void); unsigned long (*get_cpu_khz)(void); /* Segment descriptor handling */ @@ -566,7 +566,10 @@ static inline u64 paravirt_read_tsc(void) #define rdtscll(val) (val = paravirt_read_tsc()) -#define get_scheduled_cycles(val) (val = paravirt_ops.get_scheduled_cycles()) +static inline unsigned long long paravirt_sched_clock(void) +{ + return PVOP_CALL0(unsigned long long, sched_clock); +} #define calculate_cpu_khz() (paravirt_ops.get_cpu_khz()) #define write_tsc(val1,val2) wrmsr(0x10, val1, val2) diff --git a/include/asm-i386/timer.h b/include/asm-i386/timer.h index 153770e..51a713e 100644 --- a/include/asm-i386/timer.h +++ b/include/asm-i386/timer.h @@ -15,8 +15,38 @@ extern int no_sync_cmos_clock; extern int recalibrate_cpu_khz(void); #ifndef CONFIG_PARAVIRT -#define get_scheduled_cycles(val) rdtscll(val) #define calculate_cpu_khz() native_calculate_cpu_khz() #endif +/* Accellerators for sched_clock() + * convert from cycles(64bits) => nanoseconds (64bits) + * basic equation: + * ns = cycles / (freq / ns_per_sec) + * ns = cycles * (ns_per_sec / freq) + * ns = cycles * (10^9 / (cpu_khz * 10^3)) + * ns = cycles * (10^6 / cpu_khz) + * + * Then we use scaling math (suggested by george@mvista.com) to get: + * ns = cycles * (10^6 * SC / cpu_khz) / SC + * ns = cycles * cyc2ns_scale / SC + * + * And since SC is a constant power of two, we can convert the div + * into a shift. + * + * We can use khz divisor instead of mhz to keep a better percision, since + * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits. + * (mathieu.desnoyers@polymtl.ca) + * + * -johnstul@us.ibm.com "math is hard, lets go shopping!" + */ +extern unsigned long cyc2ns_scale __read_mostly; + +#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ + +static inline unsigned long long cycles_2_ns(unsigned long long cyc) +{ + return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR; +} + + #endif diff --git a/include/asm-i386/vmi_time.h b/include/asm-i386/vmi_time.h index 213930b..4781881 100644 --- a/include/asm-i386/vmi_time.h +++ b/include/asm-i386/vmi_time.h @@ -49,7 +49,7 @@ extern struct vmi_timer_ops { extern void __init vmi_time_init(void); extern unsigned long vmi_get_wallclock(void); extern int vmi_set_wallclock(unsigned long now); -extern unsigned long long vmi_get_sched_cycles(void); +extern unsigned long long vmi_sched_clock(void); extern unsigned long vmi_cpu_khz(void); #ifdef CONFIG_X86_LOCAL_APIC |
