Hi, Ralf, Loops_per_jiffy is set on startup and doesn't change later. It reflect the maximum value frequency, but for CPU hotplug, a new online CPU may not run at the maximum frequency (remain the old value before it is offline). Huacai On Tue, Nov 11, 2014 at 6:57 PM, Ralf Baechle <ralf@xxxxxxxxxxxxxx> wrote: > On Tue, Nov 04, 2014 at 02:18:48PM +0800, Huacai Chen wrote: > >> diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c >> index c94c4e9..01d676a 100644 >> --- a/arch/mips/kernel/smp.c >> +++ b/arch/mips/kernel/smp.c >> @@ -136,7 +136,8 @@ asmlinkage void start_secondary(void) >> calibrate_delay(); >> preempt_disable(); >> cpu = smp_processor_id(); >> - cpu_data[cpu].udelay_val = loops_per_jiffy; >> + if (!cpu_data[cpu].udelay_val) >> + cpu_data[cpu].udelay_val = loops_per_jiffy; > > Why this? Is the idea that the value of loops_per_jiffy which was set > on bootup may no longer match the actual clock frequency? > > Ralf >
