x86: use cpu_khz for loops_per_jiffy calculation, cleanup
As suggested by Ingo, remove all references to tsc from init/calibrate.c TSC is x86 specific, and using tsc in variable names in a generic file should be avoided. lpj_tsc is now called lpj_fine, since it is related to fine tuning of lpj value. Also tsc_rate_* is called timer_rate_* Signed-off-by: Alok N Kataria <akataria@vmware.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Daniel Hecht <dhecht@vmware.com> Cc: Tim Mann <mann@vmware.com> Cc: Zach Amsden <zach@vmware.com> Cc: Sahil Rihan <srihan@vmware.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -123,7 +123,7 @@ void __init time_init(void)
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(boot_cpu_data.x86_vendor == X86_VENDOR_AMD))
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cpu_khz = calculate_cpu_khz();
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lpj_tsc = ((unsigned long)tsc_khz * 1000)/HZ;
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lpj_fine = ((unsigned long)tsc_khz * 1000)/HZ;
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if (unsynchronized_tsc())
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mark_tsc_unstable("TSCs unsynchronized");
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@ -425,7 +425,7 @@ void __init tsc_init(void)
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lpj = ((u64)tsc_khz * 1000);
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do_div(lpj, HZ);
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lpj_tsc = lpj;
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lpj_fine = lpj;
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printk("Detected %lu.%03lu MHz processor.\n",
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(unsigned long)cpu_khz / 1000,
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@ -41,7 +41,7 @@ static inline void ndelay(unsigned long x)
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#define ndelay(x) ndelay(x)
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#endif
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extern unsigned long lpj_tsc;
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extern unsigned long lpj_fine;
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void calibrate_delay(void);
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void msleep(unsigned int msecs);
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unsigned long msleep_interruptible(unsigned int msecs);
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@ -10,7 +10,7 @@
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#include <linux/timex.h>
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#include <linux/smp.h>
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unsigned long lpj_tsc;
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unsigned long lpj_fine;
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unsigned long preset_lpj;
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static int __init lpj_setup(char *str)
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{
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@ -35,9 +35,9 @@ static unsigned long __cpuinit calibrate_delay_direct(void)
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unsigned long pre_start, start, post_start;
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unsigned long pre_end, end, post_end;
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unsigned long start_jiffies;
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unsigned long tsc_rate_min, tsc_rate_max;
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unsigned long good_tsc_sum = 0;
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unsigned long good_tsc_count = 0;
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unsigned long timer_rate_min, timer_rate_max;
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unsigned long good_timer_sum = 0;
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unsigned long good_timer_count = 0;
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int i;
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if (read_current_timer(&pre_start) < 0 )
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@ -81,22 +81,24 @@ static unsigned long __cpuinit calibrate_delay_direct(void)
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}
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read_current_timer(&post_end);
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tsc_rate_max = (post_end - pre_start) / DELAY_CALIBRATION_TICKS;
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tsc_rate_min = (pre_end - post_start) / DELAY_CALIBRATION_TICKS;
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timer_rate_max = (post_end - pre_start) /
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DELAY_CALIBRATION_TICKS;
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timer_rate_min = (pre_end - post_start) /
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DELAY_CALIBRATION_TICKS;
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/*
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* If the upper limit and lower limit of the tsc_rate is
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* If the upper limit and lower limit of the timer_rate is
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* >= 12.5% apart, redo calibration.
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*/
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if (pre_start != 0 && pre_end != 0 &&
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(tsc_rate_max - tsc_rate_min) < (tsc_rate_max >> 3)) {
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good_tsc_count++;
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good_tsc_sum += tsc_rate_max;
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(timer_rate_max - timer_rate_min) < (timer_rate_max >> 3)) {
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good_timer_count++;
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good_timer_sum += timer_rate_max;
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}
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}
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if (good_tsc_count)
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return (good_tsc_sum/good_tsc_count);
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if (good_timer_count)
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return (good_timer_sum/good_timer_count);
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printk(KERN_WARNING "calibrate_delay_direct() failed to get a good "
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"estimate for loops_per_jiffy.\nProbably due to long platform interrupts. Consider using \"lpj=\" boot option.\n");
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@ -111,8 +113,8 @@ static unsigned long __cpuinit calibrate_delay_direct(void) {return 0;}
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* bit takes on average 1.5/HZ seconds. This (like the original) is a little
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* better than 1%
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* For the boot cpu we can skip the delay calibration and assign it a value
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* calculated based on the tsc frequency.
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* For the rest of the CPUs we cannot assume that the tsc frequency is same as
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* calculated based on the timer frequency.
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* For the rest of the CPUs we cannot assume that the timer frequency is same as
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* the cpu frequency, hence do the calibration for those.
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*/
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#define LPS_PREC 8
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@ -126,11 +128,11 @@ void __cpuinit calibrate_delay(void)
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loops_per_jiffy = preset_lpj;
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printk(KERN_INFO
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"Calibrating delay loop (skipped) preset value.. ");
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} else if ((smp_processor_id() == 0) && lpj_tsc) {
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loops_per_jiffy = lpj_tsc;
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} else if ((smp_processor_id() == 0) && lpj_fine) {
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loops_per_jiffy = lpj_fine;
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printk(KERN_INFO
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"Calibrating delay loop (skipped), "
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"using tsc calculated value.. ");
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"value calculated using timer frequency.. ");
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} else if ((loops_per_jiffy = calibrate_delay_direct()) != 0) {
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printk(KERN_INFO
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"Calibrating delay using timer specific routine.. ");
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