Hi Thomas,
At 07/03/2017 03:15 AM, Thomas Gleixner wrote:
On Fri, 30 Jun 2017, Dou Liyang wrote:
+static void __init delay_with_tsc(void)
+{
+ unsigned long long start, now;
+ unsigned long ticks = jiffies;
Please make that
unsigned long end = jiffies + 4;
ticks really me
On Fri, 30 Jun 2017, Dou Liyang wrote:
> +static void __init delay_with_tsc(void)
> +{
> + unsigned long long start, now;
> + unsigned long ticks = jiffies;
Please make that
unsigned long end = jiffies + 4;
ticks really means: number of ticks. But that variable is doing something
Kernel use timer_irq_works() to detects the timer IRQs. It calls
mdelay(10) to delay ten ticks and check whether the timer IRQ work
or not. The mdelay() depends on the loops_per_jiffy which is set up
in calibrate_delay(). Current kernel defaults the IRQ 0 is available
when it calibrates delay.
But