On 08.09.2005 [14:22:13 -0700], Nishanth Aravamudan wrote:
> On 08.09.2005 [13:00:36 +0300], Tony Lindgren wrote:
> > * Nishanth Aravamudan <[EMAIL PROTECTED]> [050907 18:07]:
> > > On 07.09.2005 [10:37:43 +0300], Tony Lindgren wrote:
> > > > * Nishanth Aravamudan <[EMAIL PROTECTED]> [050905 20:02]:
> > > > > On 05.09.2005 [10:27:05 +0300], Tony Lindgren wrote:
> > > > > > * Srivatsa Vaddagiri <[EMAIL PROTECTED]> [050905 10:03]:
> > > > > > > On Sun, Sep 04, 2005 at 01:10:54PM -0700, Nishanth Aravamudan
> > > > > > > wrote:
> > > > > > > >
> > > > > > > > Also, I am a bit confused by the use of "dynamic-tick" to
> > > > > > > > describe these
> > > > > > > > changes. To me, these are all NO_IDLE_HZ implementations, as
> > > > > > > > they are
> > > > > > > > only invoked from cpu_idle() (or their equivalent) routines. I
> > > > > > > > know this
> > > > > > > > is true of s390 and the x86 code, and I believe it is true of
> > > > > > > > the ARM
> > > > > > > > code? If it were dynamic-tick, I would think we would be
> > > > > > > > adjusting the
> > > > > > > > timer interrupt frequency continuously (e.g., at the end of
> > > > > > > > __run_timers() and at every call to {add,mod,del}_timer()). I
> > > > > > > > was
> > > > > > > > working on a patch which did some renaming to no_idle_hz_timer,
> > > > > > > > etc.,
> > > > > > > > but it's mostly code churn :)
> > > > > > >
> > > > > > > Yes, the name 'dynamic-tick' is misleading!
<snipping much useful feedback and many constructive conversations>
So, after *all* that, I'm going back to dyntick (notice no hyphen though
:-P). Everyone ok with this doc?
Thanks,
Nish
- include/linux/dyntick.h
with definitions in kernel/dyntick.c
#define DYN_TICK_ENABLED (1 << 1)
#define DYN_TICK_SUITABLE (1 << 0)
#define DYN_TICK_MIN_SKIP 2
/* Abstraction of a dynamic tick source
* @state: current state
* @max_skip: current maximum number of jiffies to program h/w to skip
* @min_skip: current minimum number of jiffies to program h/w to skip
* @init: initialization routine
* @enable_dyn_tick: called via sysfs to enable interrupt skipping
* @disable_dyn_tick: called via sysfs to disable interrupt
* skipping
* @reprogram: actually interact with h/w, return number of ticks the
* h/w will skip
* @recover_time: handler for returning from skipped ticks and keeping
* time consistent
* @enter_all_cpus_idle: last cpu to go idle calls this, which should
* disable any timer source (e.g. PIT on x86)
* @exit_all_cpus_idle: first cpu to wake after @enter_all_cpus_idle has
* been called should use this to revert the
* effects of that function
*/
struct dyntick_timer {
unsigned int state;
unsigned long max_skip;
unsigned long min_skip;
int (*init) (void);
void (*enable_dyn_tick) (void);
void (*disable_dyn_tick) (void);
unsigned long (*reprogram) (unsigned long); /* return number of ticks
skipped */
unsigned long (*recover_time) (int, void *, struct pt_regs *); /*
handler in arm */
/* following empty in UP */
void (*enter_all_cpus_idle) (int);
void (*exit_all_cpus_idle) (int);
spinlock_t lock;
};
extern void dyntick_timer_register(struct dyntick_timer *new_dyntick_timer);
/* so do we need this?
Maybe it can just be static to dyntick.c and all the callable
functions will call-down to the structure members? */
extern struct dyntick_timer *current_dyntick_timer;
#ifdef CONFIG_NO_IDLE_HZ /* which means CONFIG_DYNTICK is also on */
extern void set_dyntick_max_skip(unsigned long max_skip);
extern void set_dyntick_min_skip(unsigned long min_skip);
/* return number of ticks skipped, as we can request any number
called from cpu_idle() in dyntick-enabled arch's */
extern unsigned long reprogram_dyntick(void);
extern struct tick_source * __init arch_select_tick_source(void);
/* calls select_tick_source(), then calls tick_source_register() */
extern void __init dyn_tick_init(void);
static inline int dyn_tick_enabled(void)
{
return (current_ticksource->state & DYN_TICK_ENABLED);
}
#else /* CONFIG_NO_IDLE_HZ */
static inline void set_tick_max_skip(unsigned long max_skip)
{
}
static inline void idle_reprogram_tick(void)
{
}
static inline unsigned long reprogram_tick(void)
{
return 0;
}
static inline void dyn_tick_init(void)
{
}
static inline int dyn_tick_enabled(void)
{
return 0;
}
#endif /* CONFIG_NO_IDLE_HZ */
/* Pick up arch specific header */
#include <asm/dyntick.h>
- timer.c / timer.h
/* moved from sched.c/.h */
cpumask_t no_idle_hz_cpumask;
- each arch-specific file pair needs to provide:
arch_select_tick_source();
an appropriate struct tick_source definitions, functions, etc. per
usable h/w
- include/asm-i386/dyntick.h
with defines in arch/i386/dyntick.c
/* basically already done */
- include/asm-arm/arch-omap/dyntick.h
with definitions in arch/arm/mach-omap/dyntick.c
- include/asm-s390/dyntick.h
with definitions in arch/s390/dyntick.c
-
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