From 0ef95533326a7b37d16025af9edc0c18e644b346 Mon Sep 17 00:00:00 2001 From: Alok Kataria Date: Tue, 1 Jul 2008 11:43:18 -0700 Subject: x86: merge sched_clock handling Move the basic global variable definitions and sched_clock handling in the common "tsc.c" file. - Unify notsc kernel command line handling for 32 bit and 64bit. - Functional changes for 64bit. - "tsc_disabled" is updated if "notsc" is passed at boottime. - Fallback to jiffies for sched_clock, incase notsc is passed on commandline. Signed-off-by: Alok N Kataria Signed-off-by: Dan Hecht Cc: Dan Hecht Signed-off-by: Ingo Molnar --- arch/x86/kernel/tsc_32.c | 86 ++---------------------------------------------- 1 file changed, 2 insertions(+), 84 deletions(-) (limited to 'arch/x86/kernel/tsc_32.c') diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c index 6240922e497c..dc8990056d75 100644 --- a/arch/x86/kernel/tsc_32.c +++ b/arch/x86/kernel/tsc_32.c @@ -15,52 +15,8 @@ #include "mach_timer.h" -/* native_sched_clock() is called before tsc_init(), so - we must start with the TSC soft disabled to prevent - erroneous rdtsc usage on !cpu_has_tsc processors */ -static int tsc_disabled = -1; - -/* - * On some systems the TSC frequency does not - * change with the cpu frequency. So we need - * an extra value to store the TSC freq - */ -unsigned int tsc_khz; -EXPORT_SYMBOL_GPL(tsc_khz); - -#ifdef CONFIG_X86_TSC -static int __init tsc_setup(char *str) -{ - printk(KERN_WARNING "notsc: Kernel compiled with CONFIG_X86_TSC, " - "cannot disable TSC completely.\n"); - tsc_disabled = 1; - return 1; -} -#else -/* - * disable flag for tsc. Takes effect by clearing the TSC cpu flag - * in cpu/common.c - */ -static int __init tsc_setup(char *str) -{ - setup_clear_cpu_cap(X86_FEATURE_TSC); - return 1; -} -#endif - -__setup("notsc", tsc_setup); - -/* - * code to mark and check if the TSC is unstable - * due to cpufreq or due to unsynced TSCs - */ -static int tsc_unstable; - -int check_tsc_unstable(void) -{ - return tsc_unstable; -} -EXPORT_SYMBOL_GPL(check_tsc_unstable); +extern int tsc_unstable; +extern int tsc_disabled; /* Accelerators for sched_clock() * convert from cycles(64bits) => nanoseconds (64bits) @@ -109,44 +65,6 @@ static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu) local_irq_restore(flags); } -/* - * Scheduler clock - returns current time in nanosec units. - */ -unsigned long long native_sched_clock(void) -{ - unsigned long long this_offset; - - /* - * Fall back to jiffies if there's no TSC available: - * ( But note that we still use it if the TSC is marked - * unstable. We do this because unlike Time Of Day, - * the scheduler clock tolerates small errors and it's - * very important for it to be as fast as the platform - * can achive it. ) - */ - if (unlikely(tsc_disabled)) - /* No locking but a rare wrong value is not a big deal: */ - return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ); - - /* read the Time Stamp Counter: */ - 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; -- cgit v1.2.3