diff options
Diffstat (limited to 'init/calibrate.c')
| -rw-r--r-- | init/calibrate.c | 55 |
1 files changed, 41 insertions, 14 deletions
diff --git a/init/calibrate.c b/init/calibrate.c index cfd7000c9d7..520702db9ac 100644 --- a/init/calibrate.c +++ b/init/calibrate.c @@ -9,6 +9,7 @@ #include <linux/init.h> #include <linux/timex.h> #include <linux/smp.h> +#include <linux/percpu.h> unsigned long lpj_fine; unsigned long preset_lpj; @@ -30,7 +31,7 @@ __setup("lpj=", lpj_setup); #define DELAY_CALIBRATION_TICKS ((HZ < 100) ? 1 : (HZ/100)) #define MAX_DIRECT_CALIBRATION_RETRIES 5 -static unsigned long __cpuinit calibrate_delay_direct(void) +static unsigned long calibrate_delay_direct(void) { unsigned long pre_start, start, post_start; unsigned long pre_end, end, post_end; @@ -93,9 +94,6 @@ static unsigned long __cpuinit calibrate_delay_direct(void) * If the upper limit and lower limit of the timer_rate is * >= 12.5% apart, redo calibration. */ - printk(KERN_DEBUG "calibrate_delay_direct() timer_rate_max=%lu " - "timer_rate_min=%lu pre_start=%lu pre_end=%lu\n", - timer_rate_max, timer_rate_min, pre_start, pre_end); if (start >= post_end) printk(KERN_NOTICE "calibrate_delay_direct() ignoring " "timer_rate as we had a TSC wrap around" @@ -168,7 +166,10 @@ static unsigned long __cpuinit calibrate_delay_direct(void) return 0; } #else -static unsigned long __cpuinit calibrate_delay_direct(void) {return 0;} +static unsigned long calibrate_delay_direct(void) +{ + return 0; +} #endif /* @@ -182,7 +183,7 @@ static unsigned long __cpuinit calibrate_delay_direct(void) {return 0;} */ #define LPS_PREC 8 -static unsigned long __cpuinit calibrate_delay_converge(void) +static unsigned long calibrate_delay_converge(void) { /* First stage - slowly accelerate to find initial bounds */ unsigned long lpj, lpj_base, ticks, loopadd, loopadd_base, chop_limit; @@ -246,32 +247,58 @@ recalibrate: return lpj; } -void __cpuinit calibrate_delay(void) +static DEFINE_PER_CPU(unsigned long, cpu_loops_per_jiffy) = { 0 }; + +/* + * Check if cpu calibration delay is already known. For example, + * some processors with multi-core sockets may have all cores + * with the same calibration delay. + * + * Architectures should override this function if a faster calibration + * method is available. + */ +unsigned long __attribute__((weak)) calibrate_delay_is_known(void) { + return 0; +} + +void calibrate_delay(void) +{ + unsigned long lpj; static bool printed; + int this_cpu = smp_processor_id(); - if (preset_lpj) { - loops_per_jiffy = preset_lpj; + if (per_cpu(cpu_loops_per_jiffy, this_cpu)) { + lpj = per_cpu(cpu_loops_per_jiffy, this_cpu); + if (!printed) + pr_info("Calibrating delay loop (skipped) " + "already calibrated this CPU"); + } else if (preset_lpj) { + lpj = preset_lpj; if (!printed) pr_info("Calibrating delay loop (skipped) " "preset value.. "); } else if ((!printed) && lpj_fine) { - loops_per_jiffy = lpj_fine; + lpj = lpj_fine; pr_info("Calibrating delay loop (skipped), " "value calculated using timer frequency.. "); - } else if ((loops_per_jiffy = calibrate_delay_direct()) != 0) { + } else if ((lpj = calibrate_delay_is_known())) { + ; + } else if ((lpj = calibrate_delay_direct()) != 0) { if (!printed) pr_info("Calibrating delay using timer " "specific routine.. "); } else { if (!printed) pr_info("Calibrating delay loop... "); - loops_per_jiffy = calibrate_delay_converge(); + lpj = calibrate_delay_converge(); } + per_cpu(cpu_loops_per_jiffy, this_cpu) = lpj; if (!printed) pr_cont("%lu.%02lu BogoMIPS (lpj=%lu)\n", - loops_per_jiffy/(500000/HZ), - (loops_per_jiffy/(5000/HZ)) % 100, loops_per_jiffy); + lpj/(500000/HZ), + (lpj/(5000/HZ)) % 100, lpj); + loops_per_jiffy = lpj; printed = true; } |