diff -upN reference/Documentation/filesystems/proc.txt current/Documentation/filesystems/proc.txt
--- reference/Documentation/filesystems/proc.txt Wed Jun 16 08:19:14 2004
+++ current/Documentation/filesystems/proc.txt Thu Jun 17 12:58:31 2004
@@ -39,6 +39,7 @@ Table of Contents
2.9 Appletalk
2.10 IPX
2.11 /proc/sys/fs/mqueue - POSIX message queues filesystem
+ 2.12 /proc/sys/sched - scheduler tunables
------------------------------------------------------------------------------
Preface
@@ -1850,6 +1851,92 @@ a queue must be less or equal then msg_m
maximum message size value (it is every message queue's attribute set during
its creation).
+
+2.12 /proc/sys/sched - scheduler tunables
+-----------------------------------------
+
+Useful knobs for tuning the scheduler live in /proc/sys/sched.
+
+child_penalty
+-------------
+
+Percentage of the parent's sleep_avg that children inherit. sleep_avg is
+a running average of the time a process spends sleeping. Tasks with high
+sleep_avg values are considered interactive and given a higher dynamic
+priority and a larger timeslice. You typically want this some value just
+under 100.
+
+exit_weight
+-----------
+
+When a CPU hog task exits, its parent's sleep_avg is reduced by a factor of
+exit_weight against the exiting task's sleep_avg.
+
+interactive_delta
+-----------------
+
+If a task is "interactive" it is reinserted into the active array after it
+has expired its timeslice, instead of being inserted into the expired array.
+How "interactive" a task must be in order to be deemed interactive is a
+function of its nice value. This interactive limit is scaled linearly by nice
+value and is offset by the interactive_delta.
+
+max_sleep_avg
+-------------
+
+max_sleep_avg is the largest value (in ms) stored for a task's running sleep
+average. The larger this value, the longer a task needs to sleep to be
+considered interactive (maximum interactive bonus is a function of
+max_sleep_avg).
+
+max_timeslice
+-------------
+
+Maximum timeslice, in milliseconds. This is the value given to tasks of the
+highest dynamic priority.
+
+min_timeslice
+-------------
+
+Minimum timeslice, in milliseconds. This is the value given to tasks of the
+lowest dynamic priority. Every task gets at least this slice of the processor
+per array switch.
+
+parent_penalty
+--------------
+
+Percentage of the parent's sleep_avg that it retains across a fork().
+sleep_avg is a running average of the time a process spends sleeping. Tasks
+with high sleep_avg values are considered interactive and given a higher
+dynamic priority and a larger timeslice. Normally, this value is 100 and thus
+task's retain their sleep_avg on fork. If you want to punish interactive
+tasks for forking, set this below 100.
+
+prio_bonus_ratio
+----------------
+
+Middle percentage of the priority range that tasks can receive as a dynamic
+priority. The default value of 25% ensures that nice values at the
+extremes are still enforced. For example, nice +19 interactive tasks will
+never be able to preempt a nice 0 CPU hog. Setting this higher will increase
+the size of the priority range the tasks can receive as a bonus. Setting
+this lower will decrease this range, making the interactivity bonus less
+apparent and user nice values more applicable.
+
+starvation_limit
+----------------
+
+Sufficiently interactive tasks are reinserted into the active array when they
+run out of timeslice. Normally, tasks are inserted into the expired array.
+Reinserting interactive tasks into the active array allows them to remain
+runnable, which is important to interactive performance. This could starve
+expired tasks, however, since the interactive task could prevent the array
+switch. To prevent starving the tasks on the expired array for too long. the
+starvation_limit is the longest (in ms) we will let the expired array starve
+at the expense of reinserting interactive tasks back into active. Higher
+values here give more preferance to running interactive tasks, at the expense
+of expired tasks. Lower values provide more fair scheduling behavior, at the
+expense of interactivity. The units are in milliseconds.
------------------------------------------------------------------------------
Summary
diff -upN reference/include/linux/sysctl.h current/include/linux/sysctl.h
--- reference/include/linux/sysctl.h Wed Jun 16 08:19:27 2004
+++ current/include/linux/sysctl.h Thu Jun 17 12:58:31 2004
@@ -61,7 +61,8 @@ enum
CTL_DEV=7, /* Devices */
CTL_BUS=8, /* Busses */
CTL_ABI=9, /* Binary emulation */
- CTL_CPU=10 /* CPU stuff (speed scaling, etc) */
+ CTL_CPU=10, /* CPU stuff (speed scaling, etc) */
+ CTL_SCHED=11, /* scheduler tunables */
};
/* CTL_BUS names: */
@@ -166,6 +167,18 @@ enum
VM_HUGETLB_GROUP=25, /* permitted hugetlb group */
};
+/* Tunable scheduler parameters in /proc/sys/sched/ */
+enum {
+ SCHED_MIN_TIMESLICE=1, /* minimum process timeslice */
+ SCHED_MAX_TIMESLICE=2, /* maximum process timeslice */
+ SCHED_CHILD_PENALTY=3, /* penalty on fork to child */
+ SCHED_PARENT_PENALTY=4, /* penalty on fork to parent */
+ SCHED_EXIT_WEIGHT=5, /* penalty to parent of CPU hog child */
+ SCHED_PRIO_BONUS_RATIO=6, /* percent of max prio given as bonus */
+ SCHED_INTERACTIVE_DELTA=7, /* delta used to scale interactivity */
+ SCHED_MAX_SLEEP_AVG=8, /* maximum sleep avg attainable */
+ SCHED_STARVATION_LIMIT=9, /* no re-active if expired is starved */
+};
/* CTL_NET names: */
enum
diff -upN reference/kernel/sched.c current/kernel/sched.c
--- reference/kernel/sched.c Wed Jun 16 16:08:22 2004
+++ current/kernel/sched.c Thu Jun 17 12:58:31 2004
@@ -83,18 +83,30 @@
* maximum timeslice is 200 msecs. Timeslices get refilled after
* they expire.
*/
-#define MIN_TIMESLICE ( 10 * HZ / 1000)
-#define MAX_TIMESLICE (200 * HZ / 1000)
+int min_timeslice = (10 * HZ) / 1000;
+#define MIN_TIMESLICE (min_timeslice)
+int max_timeslice = (200 * HZ) / 1000;
+#define MAX_TIMESLICE (max_timeslice)
#define ON_RUNQUEUE_WEIGHT 30
-#define CHILD_PENALTY 95
-#define PARENT_PENALTY 100
-#define EXIT_WEIGHT 3
-#define PRIO_BONUS_RATIO 25
+int child_penalty = 95;
+#define CHILD_PENALTY (child_penalty)
+int parent_penalty = 100;
+#define PARENT_PENALTY (parent_penalty)
+int exit_weight = 3;
+#define EXIT_WEIGHT (exit_weight)
+int prio_bonus_ratio = 25;
+#define PRIO_BONUS_RATIO (prio_bonus_ratio)
#define MAX_BONUS (MAX_USER_PRIO * PRIO_BONUS_RATIO / 100)
-#define INTERACTIVE_DELTA 2
+int interactive_delta = 2;
+#define INTERACTIVE_DELTA (interactive_delta)
#define MAX_SLEEP_AVG (AVG_TIMESLICE * MAX_BONUS)
#define STARVATION_LIMIT (MAX_SLEEP_AVG)
#define NS_MAX_SLEEP_AVG (JIFFIES_TO_NS(MAX_SLEEP_AVG))
+/* wasn't here, does it have an equivalent --dvhart
+ * - #define NODE_THRESHOLD 125
+ * + int node_threshold = 125;
+ * + #define NODE_THRESHOLD (node_threshold)
+ */
#define CREDIT_LIMIT 100
/*
diff -upN reference/kernel/sysctl.c current/kernel/sysctl.c
--- reference/kernel/sysctl.c Wed Jun 16 16:08:22 2004
+++ current/kernel/sysctl.c Thu Jun 17 12:58:31 2004
@@ -62,6 +62,16 @@ extern int cad_pid;
extern int pid_max;
extern int sysctl_lower_zone_protection;
extern int min_free_kbytes;
+
+/* sched_tunables variables */
+extern int min_timeslice;
+extern int max_timeslice;
+extern int child_penalty;
+extern int parent_penalty;
+extern int exit_weight;
+extern int prio_bonus_ratio;
+extern int interactive_delta;
+
extern int printk_ratelimit_jiffies;
extern int printk_ratelimit_burst;
@@ -131,6 +141,7 @@ static struct ctl_table_header root_tabl
static ctl_table kern_table[];
static ctl_table vm_table[];
+static ctl_table sched_table[];
#ifdef CONFIG_NET
extern ctl_table net_table[];
#endif
@@ -210,6 +221,12 @@ static ctl_table root_table[] = {
.mode = 0555,
.child = dev_table,
},
+ {
+ .ctl_name = CTL_SCHED,
+ .procname = "sched",
+ .mode = 0555,
+ .child = sched_table,
+ },
{ .ctl_name = 0 }
};
@@ -642,6 +659,7 @@ static ctl_table kern_table[] = {
/* Constants for minimum and maximum testing in vm_table.
We use these as one-element integer vectors. */
static int zero;
+static int one = 1;
static int one_hundred = 100;
@@ -912,6 +930,31 @@ static ctl_table debug_table[] = {
static ctl_table dev_table[] = {
{ .ctl_name = 0 }
};
+
+static ctl_table sched_table[] = {
+ {SCHED_MAX_TIMESLICE, "max_timeslice", &max_timeslice,
+ sizeof(int), 0644, NULL, &proc_dointvec_minmax,
+ &sysctl_intvec, NULL, &one, NULL},
+ {SCHED_MIN_TIMESLICE, "min_timeslice", &min_timeslice,
+ sizeof(int), 0644, NULL, &proc_dointvec_minmax,
+ &sysctl_intvec, NULL, &one, NULL},
+ {SCHED_CHILD_PENALTY, "child_penalty", &child_penalty,
+ sizeof(int), 0644, NULL, &proc_dointvec_minmax,
+ &sysctl_intvec, NULL, &zero, NULL},
+ {SCHED_PARENT_PENALTY, "parent_penalty", &parent_penalty,
+ sizeof(int), 0644, NULL, &proc_dointvec_minmax,
+ &sysctl_intvec, NULL, &zero, NULL},
+ {SCHED_EXIT_WEIGHT, "exit_weight", &exit_weight,
+ sizeof(int), 0644, NULL, &proc_dointvec_minmax,
+ &sysctl_intvec, NULL, &zero, NULL},
+ {SCHED_PRIO_BONUS_RATIO, "prio_bonus_ratio", &prio_bonus_ratio,
+ sizeof(int), 0644, NULL, &proc_dointvec_minmax,
+ &sysctl_intvec, NULL, &zero, NULL},
+ {SCHED_INTERACTIVE_DELTA, "interactive_delta", &interactive_delta,
+ sizeof(int), 0644, NULL, &proc_dointvec_minmax,
+ &sysctl_intvec, NULL, &zero, NULL},
+ {0}
+};
extern void init_irq_proc (void);