[PATCH] sched: add a tuning knob to allow changing RR tmeslice
Subject: [PATCH] sched: add a tuning knob to allow changing RR timeslice
User wanted a facility simliar to the ability on Solaris to adjust
the SCHED_RR timeslice value. Add a /proc/sys/kernel scheduler knob
named sched_rr_timeslice_ms which allows global changing of the SCHED_RR
timeslice value. User visable value is in milliseconds but is stored as
jiffies. Setting to 0 (zero) resets to the default (currently 100ms).
Patch against tip/master, currently 3.7-rc3.
Signed-off-by: Clark Williams
---
include/linux/sched.h | 6 +-
kernel/sched.c| 19 +++
kernel/sched_rt.c | 4 ++--
kernel/sysctl.c | 8
4 files changed, 34 insertions(+), 3 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 12317b6..214bf27 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2097,11 +2097,15 @@ static inline unsigned int
get_sysctl_timer_migration(void)
#endif
extern unsigned int sysctl_sched_rt_period;
extern int sysctl_sched_rt_runtime;
-
int sched_rt_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos);
+extern int sched_rr_timeslice;
+extern int sched_rr_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos);
+
#ifdef CONFIG_SCHED_AUTOGROUP
extern unsigned int sysctl_sched_autogroup_enabled;
diff --git a/kernel/sched.c b/kernel/sched.c
index cdf9484..c63c3a4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -120,6 +120,7 @@
* Timeslices get refilled after they expire.
*/
#define DEF_TIMESLICE (100 * HZ / 1000)
+int sched_rr_timeslice = DEF_TIMESLICE;
/*
* single value that denotes runtime == period, ie unlimited time.
@@ -9614,6 +9615,24 @@ static int sched_rt_global_constraints(void)
}
#endif /* CONFIG_RT_GROUP_SCHED */
+int sched_rr_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ int ret;
+ static DEFINE_MUTEX(mutex);
+
+ mutex_lock(&mutex);
+ ret = proc_dointvec(table, write, buffer, lenp, ppos);
+ /* make sure that internally we keep jiffies */
+ /* also, writing zero resets timeslice to default */
+ if (!ret && write)
+ sched_rr_timeslice = sched_rr_timeslice <= 0 ?
+ DEF_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice);
+ mutex_unlock(&mutex);
+ return ret;
+}
+
int sched_rt_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index c108b9c..799dd09 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1791,7 +1791,7 @@ static void task_tick_rt(struct rq *rq, struct
task_struct *p, int queued)
if (--p->rt.time_slice)
return;
- p->rt.time_slice = DEF_TIMESLICE;
+ p->rt.time_slice = sched_rr_timeslice;
/*
* Requeue to the end of queue if we are not the only element
@@ -1819,7 +1819,7 @@ static unsigned int get_rr_interval_rt(struct rq *rq,
struct task_struct *task)
* Time slice is 0 for SCHED_FIFO tasks
*/
if (task->policy == SCHED_RR)
- return DEF_TIMESLICE;
+ return sched_rr_timeslice;
else
return 0;
}
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index ea7ec7f..10b1129 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -362,6 +362,14 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = sched_rt_handler,
},
+ {
+ .procname = "sched_rr_timeslice_ms",
+ .data = &sched_rr_timeslice,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = sched_rr_handler,
+ },
+
#ifdef CONFIG_SCHED_AUTOGROUP
{
.procname = "sched_autogroup_enabled",
--
1.7.11.7
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Re: [PATCH] sched: add a tuning knob to allow changing RR tmeslice
On Thu, 2012-11-08 at 14:27 -0600, Clark Williams wrote:
> Subject: [PATCH] sched: add a tuning knob to allow changing RR timeslice
>
> User wanted a facility simliar to the ability on Solaris to adjust
> the SCHED_RR timeslice value. Add a /proc/sys/kernel scheduler knob
> named sched_rr_timeslice_ms which allows global changing of the SCHED_RR
> timeslice value. User visable value is in milliseconds but is stored as
> jiffies. Setting to 0 (zero) resets to the default (currently 100ms).
>
Hmm, has this been ignored?
I guess the real question, is it still needed (or wanted)?
-- Steve
> Patch against tip/master, currently 3.7-rc3.
>
> Signed-off-by: Clark Williams
> ---
> include/linux/sched.h | 6 +-
> kernel/sched.c| 19 +++
> kernel/sched_rt.c | 4 ++--
> kernel/sysctl.c | 8
> 4 files changed, 34 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 12317b6..214bf27 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -2097,11 +2097,15 @@ static inline unsigned int
> get_sysctl_timer_migration(void)
> #endif
> extern unsigned int sysctl_sched_rt_period;
> extern int sysctl_sched_rt_runtime;
> -
> int sched_rt_handler(struct ctl_table *table, int write,
> void __user *buffer, size_t *lenp,
> loff_t *ppos);
>
> +extern int sched_rr_timeslice;
> +extern int sched_rr_handler(struct ctl_table *table, int write,
> + void __user *buffer, size_t *lenp,
> + loff_t *ppos);
> +
> #ifdef CONFIG_SCHED_AUTOGROUP
> extern unsigned int sysctl_sched_autogroup_enabled;
>
> diff --git a/kernel/sched.c b/kernel/sched.c
> index cdf9484..c63c3a4 100644
> --- a/kernel/sched.c
> +++ b/kernel/sched.c
> @@ -120,6 +120,7 @@
> * Timeslices get refilled after they expire.
> */
> #define DEF_TIMESLICE(100 * HZ / 1000)
> +int sched_rr_timeslice = DEF_TIMESLICE;
>
> /*
> * single value that denotes runtime == period, ie unlimited time.
> @@ -9614,6 +9615,24 @@ static int sched_rt_global_constraints(void)
> }
> #endif /* CONFIG_RT_GROUP_SCHED */
>
> +int sched_rr_handler(struct ctl_table *table, int write,
> + void __user *buffer, size_t *lenp,
> + loff_t *ppos)
> +{
> + int ret;
> + static DEFINE_MUTEX(mutex);
> +
> + mutex_lock(&mutex);
> + ret = proc_dointvec(table, write, buffer, lenp, ppos);
> + /* make sure that internally we keep jiffies */
> + /* also, writing zero resets timeslice to default */
> + if (!ret && write)
> + sched_rr_timeslice = sched_rr_timeslice <= 0 ?
> + DEF_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice);
> + mutex_unlock(&mutex);
> + return ret;
> +}
> +
> int sched_rt_handler(struct ctl_table *table, int write,
> void __user *buffer, size_t *lenp,
> loff_t *ppos)
> diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
> index c108b9c..799dd09 100644
> --- a/kernel/sched_rt.c
> +++ b/kernel/sched_rt.c
> @@ -1791,7 +1791,7 @@ static void task_tick_rt(struct rq *rq, struct
> task_struct *p, int queued)
> if (--p->rt.time_slice)
> return;
>
> - p->rt.time_slice = DEF_TIMESLICE;
> + p->rt.time_slice = sched_rr_timeslice;
>
> /*
>* Requeue to the end of queue if we are not the only element
> @@ -1819,7 +1819,7 @@ static unsigned int get_rr_interval_rt(struct rq *rq,
> struct task_struct *task)
>* Time slice is 0 for SCHED_FIFO tasks
>*/
> if (task->policy == SCHED_RR)
> - return DEF_TIMESLICE;
> + return sched_rr_timeslice;
> else
> return 0;
> }
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index ea7ec7f..10b1129 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -362,6 +362,14 @@ static struct ctl_table kern_table[] = {
> .mode = 0644,
> .proc_handler = sched_rt_handler,
> },
> + {
> + .procname = "sched_rr_timeslice_ms",
> + .data = &sched_rr_timeslice,
> + .maxlen = sizeof(int),
> + .mode = 0644,
> + .proc_handler = sched_rr_handler,
> + },
> +
> #ifdef CONFIG_SCHED_AUTOGROUP
> {
> .procname = "sched_autogroup_enabled",
--
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Re: [PATCH] sched: add a tuning knob to allow changing RR tmeslice
On Wed, 23 Jan 2013 15:09:38 -0500
Steven Rostedt wrote:
> On Thu, 2012-11-08 at 14:27 -0600, Clark Williams wrote:
> > Subject: [PATCH] sched: add a tuning knob to allow changing RR timeslice
> >
> > User wanted a facility simliar to the ability on Solaris to adjust
> > the SCHED_RR timeslice value. Add a /proc/sys/kernel scheduler knob
> > named sched_rr_timeslice_ms which allows global changing of the SCHED_RR
> > timeslice value. User visable value is in milliseconds but is stored as
> > jiffies. Setting to 0 (zero) resets to the default (currently 100ms).
> >
>
> Hmm, has this been ignored?
>
> I guess the real question, is it still needed (or wanted)?
>
Yes, we've got a couple of customers that have been asking for it.
> -- Steve
>
> > Patch against tip/master, currently 3.7-rc3.
> >
> > Signed-off-by: Clark Williams
> > ---
> > include/linux/sched.h | 6 +-
> > kernel/sched.c| 19 +++
> > kernel/sched_rt.c | 4 ++--
> > kernel/sysctl.c | 8
> > 4 files changed, 34 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/linux/sched.h b/include/linux/sched.h
> > index 12317b6..214bf27 100644
> > --- a/include/linux/sched.h
> > +++ b/include/linux/sched.h
> > @@ -2097,11 +2097,15 @@ static inline unsigned int
> > get_sysctl_timer_migration(void)
> > #endif
> > extern unsigned int sysctl_sched_rt_period;
> > extern int sysctl_sched_rt_runtime;
> > -
> > int sched_rt_handler(struct ctl_table *table, int write,
> > void __user *buffer, size_t *lenp,
> > loff_t *ppos);
> >
> > +extern int sched_rr_timeslice;
> > +extern int sched_rr_handler(struct ctl_table *table, int write,
> > + void __user *buffer, size_t *lenp,
> > + loff_t *ppos);
> > +
> > #ifdef CONFIG_SCHED_AUTOGROUP
> > extern unsigned int sysctl_sched_autogroup_enabled;
> >
> > diff --git a/kernel/sched.c b/kernel/sched.c
> > index cdf9484..c63c3a4 100644
> > --- a/kernel/sched.c
> > +++ b/kernel/sched.c
> > @@ -120,6 +120,7 @@
> > * Timeslices get refilled after they expire.
> > */
> > #define DEF_TIMESLICE (100 * HZ / 1000)
> > +int sched_rr_timeslice = DEF_TIMESLICE;
> >
> > /*
> > * single value that denotes runtime == period, ie unlimited time.
> > @@ -9614,6 +9615,24 @@ static int sched_rt_global_constraints(void)
> > }
> > #endif /* CONFIG_RT_GROUP_SCHED */
> >
> > +int sched_rr_handler(struct ctl_table *table, int write,
> > + void __user *buffer, size_t *lenp,
> > + loff_t *ppos)
> > +{
> > + int ret;
> > + static DEFINE_MUTEX(mutex);
> > +
> > + mutex_lock(&mutex);
> > + ret = proc_dointvec(table, write, buffer, lenp, ppos);
> > + /* make sure that internally we keep jiffies */
> > + /* also, writing zero resets timeslice to default */
> > + if (!ret && write)
> > + sched_rr_timeslice = sched_rr_timeslice <= 0 ?
> > + DEF_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice);
> > + mutex_unlock(&mutex);
> > + return ret;
> > +}
> > +
> > int sched_rt_handler(struct ctl_table *table, int write,
> > void __user *buffer, size_t *lenp,
> > loff_t *ppos)
> > diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
> > index c108b9c..799dd09 100644
> > --- a/kernel/sched_rt.c
> > +++ b/kernel/sched_rt.c
> > @@ -1791,7 +1791,7 @@ static void task_tick_rt(struct rq *rq, struct
> > task_struct *p, int queued)
> > if (--p->rt.time_slice)
> > return;
> >
> > - p->rt.time_slice = DEF_TIMESLICE;
> > + p->rt.time_slice = sched_rr_timeslice;
> >
> > /*
> > * Requeue to the end of queue if we are not the only element
> > @@ -1819,7 +1819,7 @@ static unsigned int get_rr_interval_rt(struct rq *rq,
> > struct task_struct *task)
> > * Time slice is 0 for SCHED_FIFO tasks
> > */
> > if (task->policy == SCHED_RR)
> > - return DEF_TIMESLICE;
> > + return sched_rr_timeslice;
> > else
> > return 0;
> > }
> > diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> > index ea7ec7f..10b1129 100644
> > --- a/kernel/sysctl.c
> > +++ b/kernel/sysctl.c
> > @@ -362,6 +362,14 @@ static struct ctl_table kern_table[] = {
> > .mode = 0644,
> > .proc_handler = sched_rt_handler,
> > },
> > + {
> > + .procname = "sched_rr_timeslice_ms",
> > + .data = &sched_rr_timeslice,
> > + .maxlen = sizeof(int),
> > + .mode = 0644,
> > + .proc_handler = sched_rr_handler,
> > + },
> > +
> > #ifdef CONFIG_SCHED_AUTOGROUP
> > {
> > .procname = "sched_autogroup_enabled",
>
>
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