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x86: distangle user disabled TSC from unstable

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tsc_enabled is set to 0 from the command line switch "notsc" and from
the mark_tsc_unstable code. Seperate those functionalities and replace
tsc_enable with tsc_disable. This makes also the native_sched_clock()
decision when to use TSC understandable.

Preparatory patch to solve the sched_clock() issue on 32 bit.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2008-05-13 12:31:00 +02:00
parent b6db80ee13
commit 9ccc906c97
1 changed files with 10 additions and 10 deletions
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16
arch/x86/kernel/tsc_32.c
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@ -14,7 +14,7 @@
#include "mach_timer.h" #include "mach_timer.h"
static int tsc_enabled; static int tsc_disabled;
/* /*
* On some systems the TSC frequency does not * On some systems the TSC frequency does not
@ -29,7 +29,7 @@ static int __init tsc_setup(char *str)
{ {
printk(KERN_WARNING "notsc: Kernel compiled with CONFIG_X86_TSC, " printk(KERN_WARNING "notsc: Kernel compiled with CONFIG_X86_TSC, "
"cannot disable TSC completely.\n"); "cannot disable TSC completely.\n");
mark_tsc_unstable("user disabled TSC"); tsc_disabled = 1;
return 1; return 1;
} }
#else #else
@ -120,7 +120,7 @@ unsigned long long native_sched_clock(void)
* very important for it to be as fast as the platform * very important for it to be as fast as the platform
* can achive it. ) * can achive it. )
*/ */
if (unlikely(!tsc_enabled && !tsc_unstable)) if (unlikely(tsc_disabled))
/* No locking but a rare wrong value is not a big deal: */ /* No locking but a rare wrong value is not a big deal: */
return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ); return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
@ -322,7 +322,6 @@ void mark_tsc_unstable(char *reason)
{ {
if (!tsc_unstable) { if (!tsc_unstable) {
tsc_unstable = 1; tsc_unstable = 1;
tsc_enabled = 0;
printk("Marking TSC unstable due to: %s.\n", reason); printk("Marking TSC unstable due to: %s.\n", reason);
/* Can be called before registration */ /* Can be called before registration */
if (clocksource_tsc.mult) if (clocksource_tsc.mult)
@ -403,8 +402,11 @@ void __init tsc_init(void)
{ {
int cpu; int cpu;
if (!cpu_has_tsc) if (!cpu_has_tsc || tsc_disabled) {
/* Disable the TSC in case of !cpu_has_tsc */
tsc_disabled = 1;
return; return;
}
cpu_khz = calculate_cpu_khz(); cpu_khz = calculate_cpu_khz();
tsc_khz = cpu_khz; tsc_khz = cpu_khz;
@ -441,8 +443,6 @@ void __init tsc_init(void)
if (check_tsc_unstable()) { if (check_tsc_unstable()) {
clocksource_tsc.rating = 0; clocksource_tsc.rating = 0;
clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS; clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
} else }
tsc_enabled = 1;
clocksource_register(&clocksource_tsc); clocksource_register(&clocksource_tsc);
} }