diff options
| -rw-r--r-- | arch/x86/kernel/time_64.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/tsc_32.c | 6 | ||||
| -rw-r--r-- | arch/x86/lib/delay_32.c | 25 | ||||
| -rw-r--r-- | include/linux/delay.h | 1 | ||||
| -rw-r--r-- | init/calibrate.c | 60 |
5 files changed, 57 insertions, 37 deletions
diff --git a/arch/x86/kernel/time_64.c b/arch/x86/kernel/time_64.c index c737849e2ef7..39ae8511a137 100644 --- a/arch/x86/kernel/time_64.c +++ b/arch/x86/kernel/time_64.c @@ -123,6 +123,8 @@ void __init time_init(void) (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)) cpu_khz = calculate_cpu_khz(); + lpj_fine = ((unsigned long)tsc_khz * 1000)/HZ; + if (unsynchronized_tsc()) mark_tsc_unstable("TSCs unsynchronized"); diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c index 65b70637ad97..0065426f1511 100644 --- a/arch/x86/kernel/tsc_32.c +++ b/arch/x86/kernel/tsc_32.c @@ -1,6 +1,7 @@ #include <linux/sched.h> #include <linux/clocksource.h> #include <linux/workqueue.h> +#include <linux/delay.h> #include <linux/cpufreq.h> #include <linux/jiffies.h> #include <linux/init.h> @@ -404,6 +405,7 @@ static inline void check_geode_tsc_reliable(void) { } void __init tsc_init(void) { int cpu; + u64 lpj; if (!cpu_has_tsc || tsc_disabled > 0) return; @@ -416,6 +418,10 @@ void __init tsc_init(void) return; } + lpj = ((u64)tsc_khz * 1000); + do_div(lpj, HZ); + lpj_fine = lpj; + /* now allow native_sched_clock() to use rdtsc */ tsc_disabled = 0; diff --git a/arch/x86/lib/delay_32.c b/arch/x86/lib/delay_32.c index d710f2d167bb..ef691316f8b6 100644 --- a/arch/x86/lib/delay_32.c +++ b/arch/x86/lib/delay_32.c @@ -3,6 +3,7 @@ * * Copyright (C) 1993 Linus Torvalds * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> + * Copyright (C) 2008 Jiri Hladky <hladky _dot_ jiri _at_ gmail _dot_ com> * * The __delay function must _NOT_ be inlined as its execution time * depends wildly on alignment on many x86 processors. The additional @@ -28,16 +29,22 @@ /* simple loop based delay: */ static void delay_loop(unsigned long loops) { - int d0; - __asm__ __volatile__( - "\tjmp 1f\n" - ".align 16\n" - "1:\tjmp 2f\n" - ".align 16\n" - "2:\tdecl %0\n\tjns 2b" - :"=&a" (d0) - :"0" (loops)); + " test %0,%0 \n" + " jz 3f \n" + " jmp 1f \n" + + ".align 16 \n" + "1: jmp 2f \n" + + ".align 16 \n" + "2: decl %0 \n" + " jnz 2b \n" + "3: decl %0 \n" + + : /* we don't need output */ + :"a" (loops) + ); } /* TSC based delay: */ diff --git a/include/linux/delay.h b/include/linux/delay.h index 54552d21296e..fd832c6d419e 100644 --- a/include/linux/delay.h +++ b/include/linux/delay.h @@ -41,6 +41,7 @@ static inline void ndelay(unsigned long x) #define ndelay(x) ndelay(x) #endif +extern unsigned long lpj_fine; void calibrate_delay(void); void msleep(unsigned int msecs); unsigned long msleep_interruptible(unsigned int msecs); diff --git a/init/calibrate.c b/init/calibrate.c index ecb3822d4f70..7963e3fc51d9 100644 --- a/init/calibrate.c +++ b/init/calibrate.c @@ -8,7 +8,9 @@ #include <linux/delay.h> #include <linux/init.h> #include <linux/timex.h> +#include <linux/smp.h> +unsigned long lpj_fine; unsigned long preset_lpj; static int __init lpj_setup(char *str) { @@ -33,9 +35,9 @@ static unsigned long __cpuinit calibrate_delay_direct(void) unsigned long pre_start, start, post_start; unsigned long pre_end, end, post_end; unsigned long start_jiffies; - unsigned long tsc_rate_min, tsc_rate_max; - unsigned long good_tsc_sum = 0; - unsigned long good_tsc_count = 0; + unsigned long timer_rate_min, timer_rate_max; + unsigned long good_timer_sum = 0; + unsigned long good_timer_count = 0; int i; if (read_current_timer(&pre_start) < 0 ) @@ -79,22 +81,24 @@ static unsigned long __cpuinit calibrate_delay_direct(void) } read_current_timer(&post_end); - tsc_rate_max = (post_end - pre_start) / DELAY_CALIBRATION_TICKS; - tsc_rate_min = (pre_end - post_start) / DELAY_CALIBRATION_TICKS; + timer_rate_max = (post_end - pre_start) / + DELAY_CALIBRATION_TICKS; + timer_rate_min = (pre_end - post_start) / + DELAY_CALIBRATION_TICKS; /* - * If the upper limit and lower limit of the tsc_rate is + * If the upper limit and lower limit of the timer_rate is * >= 12.5% apart, redo calibration. */ if (pre_start != 0 && pre_end != 0 && - (tsc_rate_max - tsc_rate_min) < (tsc_rate_max >> 3)) { - good_tsc_count++; - good_tsc_sum += tsc_rate_max; + (timer_rate_max - timer_rate_min) < (timer_rate_max >> 3)) { + good_timer_count++; + good_timer_sum += timer_rate_max; } } - if (good_tsc_count) - return (good_tsc_sum/good_tsc_count); + if (good_timer_count) + return (good_timer_sum/good_timer_count); printk(KERN_WARNING "calibrate_delay_direct() failed to get a good " "estimate for loops_per_jiffy.\nProbably due to long platform interrupts. Consider using \"lpj=\" boot option.\n"); @@ -108,6 +112,10 @@ static unsigned long __cpuinit calibrate_delay_direct(void) {return 0;} * This is the number of bits of precision for the loops_per_jiffy. Each * bit takes on average 1.5/HZ seconds. This (like the original) is a little * better than 1% + * For the boot cpu we can skip the delay calibration and assign it a value + * calculated based on the timer frequency. + * For the rest of the CPUs we cannot assume that the timer frequency is same as + * the cpu frequency, hence do the calibration for those. */ #define LPS_PREC 8 @@ -118,20 +126,20 @@ void __cpuinit calibrate_delay(void) if (preset_lpj) { loops_per_jiffy = preset_lpj; - printk("Calibrating delay loop (skipped)... " - "%lu.%02lu BogoMIPS preset\n", - loops_per_jiffy/(500000/HZ), - (loops_per_jiffy/(5000/HZ)) % 100); + printk(KERN_INFO + "Calibrating delay loop (skipped) preset value.. "); + } else if ((smp_processor_id() == 0) && lpj_fine) { + loops_per_jiffy = lpj_fine; + printk(KERN_INFO + "Calibrating delay loop (skipped), " + "value calculated using timer frequency.. "); } else if ((loops_per_jiffy = calibrate_delay_direct()) != 0) { - printk("Calibrating delay using timer specific routine.. "); - printk("%lu.%02lu BogoMIPS (lpj=%lu)\n", - loops_per_jiffy/(500000/HZ), - (loops_per_jiffy/(5000/HZ)) % 100, - loops_per_jiffy); + printk(KERN_INFO + "Calibrating delay using timer specific routine.. "); } else { loops_per_jiffy = (1<<12); - printk(KERN_DEBUG "Calibrating delay loop... "); + printk(KERN_INFO "Calibrating delay loop... "); while ((loops_per_jiffy <<= 1) != 0) { /* wait for "start of" clock tick */ ticks = jiffies; @@ -161,12 +169,8 @@ void __cpuinit calibrate_delay(void) if (jiffies != ticks) /* longer than 1 tick */ loops_per_jiffy &= ~loopbit; } - - /* Round the value and print it */ - printk("%lu.%02lu BogoMIPS (lpj=%lu)\n", - loops_per_jiffy/(500000/HZ), - (loops_per_jiffy/(5000/HZ)) % 100, - loops_per_jiffy); } - + printk(KERN_INFO "%lu.%02lu BogoMIPS (lpj=%lu)\n", + loops_per_jiffy/(500000/HZ), + (loops_per_jiffy/(5000/HZ)) % 100, loops_per_jiffy); } |