Hi all,
this is a not fully serious (this is why I only post it here without sendig it
directly via mail) patchset for:
* tune the scheduler at configuration point
* increase the ticker-frequency way above 1000Hz
* tune the ticker-freq. from userspace during runtime
Of course this increases your systems overhead, but it enables you to have
more timer-triggered contexswitches per second and so (?)higher(?) interactivity.
(Of course after tuning some scheduler-parameters, min_gran, wakeup_gran ...)
An interesting feature might be the userspace controlling of the tickerfreq, too.
(Without disturbing HZ-dependend kernelcode, of course.)
I don't have very high hopes for an mainline integration ;-) but perhaps
there are people, who want to play with such stuff.
The Code is more or less an excerise and perhaps some reviewing would
be nice - so please contact me.
If (in the very unlikely case) there is enough interest in it, I can cleanup
the code and start maintaining it...
* The patch is diffed against 3.2.7
* The whole patchset is also downloadable as an bzipped archive at:
http://www.matrixstorm.com/software/linux/nitromethane/linux-3.2.7-patches.tar.bz2
So now, please blame me "we don't need such s*it, it causes only overhead"... ;-)
regards Stephan
pub 4096R/FB9B12DB 2011-10-14 Stephan Bärwolf <[email protected]>
Primary key fingerprint: 2252 B41E 12DF 41AD 476F 7F36 084A 0911 FB9B 12DB
Stephan Baerwolf (10):
menuconfig: implement new submenu for extended scheduler-options
sched: implement the new menuconfig controlling of sched_tunables
menuconfig: extend nitro-menu by responsiveness nitro options
sched: implement the controlling of responsiveness-nitro-options
menuconfig: extend nitro-menu by HZ-frequency Nitro
hrtimer: implement the controlling of nitro-hzboost
menuconfig: extend nitro-menu by priority-nitro
sched: implement the controlling of priority-nitro
menuconfig: extend nitro-menu by userspace-multiplier
hrtimer/sysctl: implement the controlling of userspace multiplier
arch/x86/Kconfig | 4 +-
include/linux/sched.h | 8 ++
kernel/Kconfig.hz | 3 -
kernel/Kconfig.sched | 202 +++++++++++++++++++++++++++++++++++++++++++
kernel/sched.c | 9 ++
kernel/sched_fair.c | 58 +++++++++++--
kernel/sysctl.c | 16 ++++
kernel/time/tick-common.c | 33 +++++++
kernel/time/tick-internal.h | 20 ++++
kernel/time/tick-sched.c | 51 +++++++++++
10 files changed, 390 insertions(+), 14 deletions(-)
create mode 100644 kernel/Kconfig.sched
--
1.7.3.4
This patch extends the conventional "nitro_hzmultiplicator" into a permille-base.
So now it is possible also to scale down HZ. (For example half HZ would be possible
with nitro_hz_permille=500, a quarter nitro_hz_permille=250 ...etc...)
As always, jiffies_64 increases with HZ frequency.
The new proc-file is called "nitro_hz_permille"
The new config-option is called "CONFIG_SCHED_NITRO_HZBOOST_PERMILLE"
Signed-off-by: Stephan Baerwolf <[email protected]>
---
kernel/Kconfig.sched | 17 +++++++++--------
kernel/sysctl.c | 12 ++++++------
kernel/time/tick-common.c | 14 +++++++-------
kernel/time/tick-internal.h | 19 ++++++++++++++-----
4 files changed, 36 insertions(+), 26 deletions(-)
diff --git a/kernel/Kconfig.sched b/kernel/Kconfig.sched
index 27e5518..a066434 100644
--- a/kernel/Kconfig.sched
+++ b/kernel/Kconfig.sched
@@ -176,23 +176,24 @@ config SCHED_NITRO_HZBOOST_USERSPAC
accessable from userspace via procfs.
The responsible file will be called /proc/sys/kernel/nitro_hzmultiplicator
-config SCHED_NITRO_HZBOOST_MULTIPLICATOR
- int "Multiply the HZ frequency value"
- range 1 100
- default 1
+config SCHED_NITRO_HZBOOST_PERMILLE
+ int "Skale the HZ frequency value (per mille)"
+ range 1 100000
+ default 1000
depends on (SCHED_NITRO_HZBOOST && X86_64 && SCHED_HRTICK)
help
Normally the scheduler code (scheduler_tick()) ticks with "HZ" frequency.
With this frequency also "jiffies_64" is increased and is used by
timerelated kernelcode.
- This Option increases the schedulers tickerfrequency by multiplying
- this multiplicator with HZ. However the jiffies_64 is STILL updated
- with HZ-frequency and all the jiffy-based timecode is working further on.
+ This Option skales the schedulers tickerfrequency by multiplying
+ this per-mille value with HZ (and divides everything by 1000).
+ However the jiffies_64 is STILL updated with HZ-frequency and all the
+ jiffy-based timecode is working further on.
Asyncron ns-time-based code will take advantage from this option and
scheduling will become finer and more interactive.
- WARNING: !! THIS OPTION WILL INCREASE YOUR "INTERRUPTS PER SECOND" FOR
+ WARNING: !! THIS OPTION MAY INCREASE YOUR "INTERRUPTS PER SECOND" FOR
EACH ONLINE CPU. THIS WILL ALSO INCREASE YOUR SYSTEMOVERHEAD !!
endmenu
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 6c95dfe..f8cec40 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -253,8 +253,8 @@ static struct ctl_table root_table[] = {
#ifdef CONFIG_SCHED_NITRO_HZBOOST_USERSPAC
#include "time/tick-internal.h"
-static int min_tick_period_HZmultiplicator = 1;
-static int max_tick_period_HZmultiplicator = 100;
+static int min_tick_period_HZscalepermille = 1;
+static int max_tick_period_HZscalepermille = 100000;
#endif
#ifdef CONFIG_SCHED_DEBUG
static int min_sched_granularity_ns = 100000; /* 100 usecs */
@@ -280,13 +280,13 @@ static struct ctl_table kern_table[] = {
},
#ifdef CONFIG_SCHED_NITRO_HZBOOST_USERSPAC
{
- .procname = "nitro_hzmultiplicator",
- .data = &sysctl_tick_period_HZmultiplicator,
+ .procname = "nitro_hz_permille",
+ .data = &sysctl_tick_period_HZscalepermille,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = tick_change_periodmultiplicator_handler,
- .extra1 = &min_tick_period_HZmultiplicator,
- .extra2 = &max_tick_period_HZmultiplicator,
+ .extra1 = &min_tick_period_HZscalepermille,
+ .extra2 = &max_tick_period_HZscalepermille,
},
#endif
#ifdef CONFIG_SCHED_DEBUG
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 1c62de8..a0176e245 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -170,7 +170,7 @@ static void tick_setup_device(struct tick_device *td,
tick_next_period = ktime_get();
#ifdef CONFIG_SCHED_NITRO_HZBOOST
tick_HZbaseperiod = ktime_set(0, NSEC_PER_SEC / HZ);
- tick_change_periodmultiplicator(CONFIG_SCHED_NITRO_HZBOOST_MULTIPLICATOR);
+ tick_change_periodmultiplicator(CONFIG_SCHED_NITRO_HZBOOST_PERMILLE);
#else
tick_period = ktime_set(0, NSEC_PER_SEC / HZ);
#endif
@@ -427,8 +427,8 @@ void __init tick_init(void)
}
#ifdef CONFIG_SCHED_NITRO_HZBOOST_USERSPAC
-unsigned int sysctl_tick_period_HZmultiplicator = ((unsigned long)CONFIG_SCHED_NITRO_HZBOOST_MULTIPLICATOR);
-static unsigned int __last_HZmultiplicator = ((unsigned long)CONFIG_SCHED_NITRO_HZBOOST_MULTIPLICATOR);
+unsigned int sysctl_tick_period_HZscalepermille = ((unsigned long)CONFIG_SCHED_NITRO_HZBOOST_PERMILLE);
+static unsigned int __last_HZscalepermille = ((unsigned long)CONFIG_SCHED_NITRO_HZBOOST_PERMILLE);
int tick_change_periodmultiplicator_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
@@ -439,11 +439,11 @@ int tick_change_periodmultiplicator_handler(struct ctl_table *table, int write,
if (ret || !write)
return ret;
- if (sysctl_tick_period_HZmultiplicator > 0)
- if (__last_HZmultiplicator != sysctl_tick_period_HZmultiplicator) {
+ if (sysctl_tick_period_HZscalepermille > 0)
+ if (__last_HZscalepermille != sysctl_tick_period_HZscalepermille) {
write_seqlock(&xtime_lock);
- tick_change_periodmultiplicator(sysctl_tick_period_HZmultiplicator);
- __last_HZmultiplicator = sysctl_tick_period_HZmultiplicator;
+ tick_change_periodmultiplicator(sysctl_tick_period_HZscalepermille);
+ __last_HZscalepermille = sysctl_tick_period_HZscalepermille;
write_sequnlock(&xtime_lock);
}
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index eb60d32..26a1bda 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -17,19 +17,28 @@ extern int tick_do_timer_cpu __read_mostly;
#ifdef CONFIG_SCHED_NITRO_HZBOOST
extern ktime_t tick_HZbaseperiod;
#ifdef CONFIG_SCHED_NITRO_HZBOOST_USERSPAC
-extern unsigned int sysctl_tick_period_HZmultiplicator;
+extern unsigned int sysctl_tick_period_HZscalepermille;
extern int tick_change_periodmultiplicator_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos);
#endif
/*
* proper locking has to be taken care outside
+ *
+ * scalepermille better be not zero!
+ *
*/
-static inline void tick_change_periodmultiplicator(const unsigned long long multiplicator)
+static inline void tick_change_periodmultiplicator(const unsigned long long scalepermille)
{
- printk( KERN_NOTICE "changing nitro hzboost multiplicator, new frequency: %llu x %lluHz\n", multiplicator, (unsigned long long)HZ);
- tick_period = ktime_set(0, NSEC_PER_SEC / (HZ*multiplicator));
- printk( KERN_NOTICE "scheduler nitro-patchset v1.0 Ilmenau 2012, by Stephan Baerwolf <[email protected]>\n");
+ unsigned long long __nanoseconds = (((unsigned long long)NSEC_PER_SEC) * 1000ULL) / scalepermille;
+ unsigned int i,j;
+
+ i = scalepermille / 1000;
+ j = scalepermille % 1000;
+
+ printk( KERN_NOTICE "changing nitro hzboost multiplicator, new frequency: %u.%03u x %lluHz\n", i, j, (unsigned long long)HZ);
+ tick_period = ktime_set(0, __nanoseconds / ((unsigned long long)HZ));
+ printk( KERN_NOTICE "scheduler nitro-patchset v1.0.1 Ilmenau 2012, by Stephan Baerwolf <[email protected]>\n");
}
#endif
--
1.7.3.4