Messages in this thread Patch in this message | | | Date | Thu, 2 Jan 2003 22:45:02 +0100 | From | Dominik Brodowski <> | Subject | [PATCH 2.5.54] cpufreq: update timer notifiers |
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- The global loops_per_jiffy can only be safely adjusted on UP. - x86 per-CPU loops_per_jiffy is not dependend of TSC, so move it to non-TSC code. - Save reference values so that rounding errors do not accumulate
diff -ruN linux-original/arch/i386/kernel/cpu/common.c linux/arch/i386/kernel/cpu/common.c --- linux-original/arch/i386/kernel/cpu/common.c 2003-01-02 22:03:50.000000000 +0100 +++ linux/arch/i386/kernel/cpu/common.c 2003-01-02 21:03:31.000000000 +0100 @@ -1,5 +1,7 @@ #include <linux/init.h> #include <linux/string.h> +#include <linux/cpufreq.h> +#include <linux/notifier.h> #include <linux/delay.h> #include <linux/smp.h> #include <asm/semaphore.h> @@ -45,6 +47,41 @@ } __setup("cachesize=", cachesize_setup); +#ifdef CONFIG_CPU_FREQ +static unsigned long loops_per_jiffy_ref = 0; +static unsigned int ref_freq = 0; + +static int +loops_per_jiffy_cpufreq_notifier(struct notifier_block *nb, unsigned long val, + void *data) +{ + struct cpufreq_freqs *freq = data; + + if (!loops_per_jiffy_ref) { + loops_per_jiffy_ref = cpu_data[freq->cpu].loops_per_jiffy; + ref_freq = freq->old; + } + + switch (val) { + case CPUFREQ_PRECHANGE: + if (freq->old < freq->new) + cpu_data[freq->cpu].loops_per_jiffy = cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new); + break; + case CPUFREQ_POSTCHANGE: + if (freq->new < freq->old) + cpu_data[freq->cpu].loops_per_jiffy = cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new); + break; + } + + return 0; +} + +static struct notifier_block loops_per_jiffy_cpufreq_notifier_block = { + .notifier_call = loops_per_jiffy_cpufreq_notifier +}; +#endif + + int __init get_model_name(struct cpuinfo_x86 *c) { unsigned int *v; @@ -354,6 +391,16 @@ boot_cpu_data.x86_capability[i] &= c->x86_capability[i]; } + /* + * Update the per-CPU loops_per_jiffy count on CPU frequency + * transitions + */ +#ifdef CONFIG_CPU_FREQ + if (c == &boot_cpu_data) { + cpufreq_register_notifier(&loops_per_jiffy_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); + } +#endif + /* Init Machine Check Exception if available. */ #ifdef CONFIG_X86_MCE mcheck_init(c); diff -ruN linux-original/arch/i386/kernel/timers/timer_tsc.c linux/arch/i386/kernel/timers/timer_tsc.c --- linux-original/arch/i386/kernel/timers/timer_tsc.c 2003-01-02 22:03:50.000000000 +0100 +++ linux/arch/i386/kernel/timers/timer_tsc.c 2003-01-02 22:03:34.000000000 +0100 @@ -188,47 +188,47 @@ } -#ifdef CONFIG_CPU_FREQ +#if defined(CONFIG_CPU_FREQ) && !defined(CONFIG_SMP) + +static unsigned long fast_gettimeoffset_ref = 0; +static unsigned long cpu_khz_ref = 0; +static unsigned int ref_freq = 0; static int -time_cpufreq_notifier(struct notifier_block *nb, unsigned long val, +tsc_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data) { struct cpufreq_freqs *freq = data; - unsigned int i; - if (!cpu_has_tsc) + if (!use_tsc) return 0; + if (!fast_gettimeoffset_ref) { + fast_gettimeoffset_ref = fast_gettimeoffset_quotient; + cpu_khz_ref = cpu_khz; + ref_freq = freq->old; + } + switch (val) { case CPUFREQ_PRECHANGE: - if ((freq->old < freq->new) && - ((freq->cpu == CPUFREQ_ALL_CPUS) || (freq->cpu == 0))) { - cpu_khz = cpufreq_scale(cpu_khz, freq->old, freq->new); - fast_gettimeoffset_quotient = cpufreq_scale(fast_gettimeoffset_quotient, freq->new, freq->old); + if (freq->old < freq->new) { + fast_gettimeoffset_quotient = cpufreq_scale(fast_gettimeoffset_ref, freq->new, ref_freq); + cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new); } - for (i=0; i<NR_CPUS; i++) - if ((freq->cpu == CPUFREQ_ALL_CPUS) || (freq->cpu == i)) - cpu_data[i].loops_per_jiffy = cpufreq_scale(cpu_data[i].loops_per_jiffy, freq->old, freq->new); break; - case CPUFREQ_POSTCHANGE: - if ((freq->new < freq->old) && - ((freq->cpu == CPUFREQ_ALL_CPUS) || (freq->cpu == 0))) { - cpu_khz = cpufreq_scale(cpu_khz, freq->old, freq->new); - fast_gettimeoffset_quotient = cpufreq_scale(fast_gettimeoffset_quotient, freq->new, freq->old); + if (freq->new < freq->old) { + fast_gettimeoffset_quotient = cpufreq_scale(fast_gettimeoffset_ref, freq->new, ref_freq); + cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new); } - for (i=0; i<NR_CPUS; i++) - if ((freq->cpu == CPUFREQ_ALL_CPUS) || (freq->cpu == i)) - cpu_data[i].loops_per_jiffy = cpufreq_scale(cpu_data[i].loops_per_jiffy, freq->old, freq->new); break; } return 0; } -static struct notifier_block time_cpufreq_notifier_block = { - .notifier_call = time_cpufreq_notifier +static struct notifier_block tsc_cpufreq_notifier_block = { + .notifier_call = tsc_cpufreq_notifier }; #endif @@ -282,8 +282,8 @@ "0" (eax), "1" (edx)); printk("Detected %lu.%03lu MHz processor.\n", cpu_khz / 1000, cpu_khz % 1000); } -#ifdef CONFIG_CPU_FREQ - cpufreq_register_notifier(&time_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); +#if defined(CONFIG_CPU_FREQ) && !defined(CONFIG_SMP) + cpufreq_register_notifier(&tsc_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); #endif return 0; } diff -ruN linux-original/kernel/cpufreq.c linux/kernel/cpufreq.c --- linux-original/kernel/cpufreq.c 2003-01-02 22:03:50.000000000 +0100 +++ linux/kernel/cpufreq.c 2003-01-02 21:03:31.000000000 +0100 @@ -927,17 +927,27 @@ * adjust_jiffies - adjust the system "loops_per_jiffy" * * This function alters the system "loops_per_jiffy" for the clock - * speed change. Note that loops_per_jiffy is only updated if all - * CPUs are affected - else there is a need for per-CPU loops_per_jiffy - * values which are provided by various architectures. + * speed change. Note that loops_per_jiffy cannot be updated on SMP + * systems as each CPU might be scaled differently. So, use the arch + * per-CPU loops_per_jiffy value wherever possible. */ +#ifndef CONFIG_SMP +static unsigned long l_p_j_ref = 0; +static unsigned int l_p_j_ref_freq = 0; + static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { + if (!l_p_j_ref_freq) { + l_p_j_ref = loops_per_jiffy; + l_p_j_ref_freq = ci->old; + } if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) || (val == CPUFREQ_POSTCHANGE && ci->old > ci->new)) - if (ci->cpu == CPUFREQ_ALL_CPUS) - loops_per_jiffy = cpufreq_scale(loops_per_jiffy, ci->old, ci->new); + loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new); } +#else +#define adjust_jiffies(...) +#endif /** - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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