1/9: cpurc_load_estimation
This patch corresponds to section 1 in Documentation/res_group/cpurc-internals,
adding load estimation of task in a resource group that is
grouped by the cpurc structure. Load estimation is necessary for controlling
CPU resource because the CPU resource controller need to know whether
the resource assigned to a resource group is enough or not.
Signed-off-by: Kurosawa Takahiro <[email protected]>
Signed-off-by: MAEDA Naoaki <[email protected]>
include/linux/cpu_rc.h | 65 ++++++++++++++++++++++++++++++++++++++++
include/linux/sched.h | 5 +++
init/Kconfig | 9 +++++
kernel/Makefile | 1
kernel/cpu_rc.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++
kernel/exit.c | 2 +
kernel/sched.c | 14 ++++++++
7 files changed, 175 insertions(+)
Index: linux-2.6.17-rc3/include/linux/cpu_rc.h
===================================================================
--- /dev/null
+++ linux-2.6.17-rc3/include/linux/cpu_rc.h
@@ -0,0 +1,65 @@
+#ifndef _LINUX_CPU_RC_H_
+#define _LINUX_CPU_RC_H_
+/*
+ * CPU resource controller interface
+ *
+ * Copyright 2005-2006 FUJITSU LIMITED
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of the Linux
+ * distribution for more details.
+ */
+
+#include <linux/config.h>
+#include <linux/sched.h>
+
+#ifdef CONFIG_CPU_RC
+
+#define CPU_RC_SPREAD_PERIOD (10 * HZ)
+#define CPU_RC_LOAD_SCALE (2 * CPU_RC_SPREAD_PERIOD)
+#define CPU_RC_GUAR_SCALE 100
+
+struct cpu_rc_domain {
+ spinlock_t lock;
+ unsigned long timestamp;
+ cpumask_t cpus;
+ int numcpus;
+ int numcrs;
+};
+
+struct cpu_rc {
+ struct cpu_rc_domain *rcd;
+ struct {
+ unsigned long timestamp;
+ unsigned int load;
+ } stat[NR_CPUS]; /* XXX need alignment */
+};
+
+extern struct cpu_rc *cpu_rc_get(task_t *);
+extern unsigned int cpu_rc_load(struct cpu_rc *);
+extern void cpu_rc_account(task_t *, unsigned long);
+
+static inline void cpu_rc_record_allocation(task_t *tsk,
+ unsigned int slice,
+ unsigned long now)
+{
+ if (slice == 0) {
+ /* minimal allocated time_slice is 1 (see sched_fork()). */
+ slice = 1;
+ }
+
+ tsk->last_slice = slice;
+ tsk->ts_alloced = now;
+}
+
+#else /* CONFIG_CPU_RC */
+
+static inline void cpu_rc_account(task_t *tsk, unsigned long now) {}
+static inline void cpu_rc_record_allocation(task_t *tsk,
+ unsigned int slice,
+ unsigned long now) {}
+
+#endif /* CONFIG_CPU_RC */
+
+#endif /* _LINUX_CPU_RC_H_ */
+
Index: linux-2.6.17-rc3/include/linux/sched.h
===================================================================
--- linux-2.6.17-rc3.orig/include/linux/sched.h
+++ linux-2.6.17-rc3/include/linux/sched.h
@@ -892,6 +892,11 @@ struct task_struct {
struct resource_group *res_group;
struct list_head member_list; /* list of tasks in the resource group */
#endif /* CONFIG_RES_GROUPS */
+#ifdef CONFIG_CPU_RC
+ unsigned int last_slice;
+ unsigned long ts_alloced;
+#endif
+
};
static inline pid_t process_group(struct task_struct *tsk)
Index: linux-2.6.17-rc3/init/Kconfig
===================================================================
--- linux-2.6.17-rc3.orig/init/Kconfig
+++ linux-2.6.17-rc3/init/Kconfig
@@ -261,6 +261,15 @@ config RELAY
If unsure, say N.
+config CPU_RC
+ bool "CPU resource controller"
+ depends on RES_GROUPS_RES_CPU
+ help
+ This options will let you control the CPU resource by scaling
+ the timeslice allocated for each tasks.
+
+ Say N if unsure.
+
source "usr/Kconfig"
config UID16
Index: linux-2.6.17-rc3/kernel/Makefile
===================================================================
--- linux-2.6.17-rc3.orig/kernel/Makefile
+++ linux-2.6.17-rc3/kernel/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_KEXEC) += kexec.o
obj-$(CONFIG_COMPAT) += compat.o
obj-$(CONFIG_CPUSETS) += cpuset.o
+obj-$(CONFIG_CPU_RC) += cpu_rc.o
obj-$(CONFIG_IKCONFIG) += configs.o
obj-$(CONFIG_STOP_MACHINE) += stop_machine.o
obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
Index: linux-2.6.17-rc3/kernel/cpu_rc.c
===================================================================
--- /dev/null
+++ linux-2.6.17-rc3/kernel/cpu_rc.c
@@ -0,0 +1,79 @@
+/*
+ * kernel/cpu_rc.c
+ *
+ * CPU resource controller by scaling time_slice of the task.
+ *
+ * Copyright 2005-2006 FUJITSU LIMITED
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of the Linux
+ * distribution for more details.
+ */
+
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/cpu_rc.h>
+
+/*
+ * cpu_rc_load() calculates a resource group load
+ */
+unsigned int cpu_rc_load(struct cpu_rc *cr)
+{
+ unsigned int load;
+ int i, n;
+
+ BUG_ON(!cr);
+
+ load = 0;
+ n = 0;
+
+ /* Just reading the value, so no locking... */
+ for_each_cpu_mask(i, cr->rcd->cpus) {
+ if (jiffies - cr->stat[i].timestamp <= CPU_RC_SPREAD_PERIOD)
+ load += cr->stat[i].load;
+ n++;
+ }
+
+ return load / n * CPU_RC_GUAR_SCALE / CPU_RC_LOAD_SCALE;
+}
+
+/*
+ * cpu_rc_account() calculates the task load when the timeslice is expired
+ */
+void cpu_rc_account(task_t *tsk, unsigned long now)
+{
+ struct cpu_rc *cr;
+ int cpu = get_cpu();
+ unsigned long last;
+ unsigned int resgrp_load, tsk_load;
+ unsigned long base, update;
+
+ if (tsk == idle_task(task_cpu(tsk)))
+ goto out;
+
+ cr = cpu_rc_get(tsk);
+ if (!cr)
+ goto out;
+
+ base = now - tsk->ts_alloced;
+ if (base == 0)
+ goto out; /* duration too small. can not collect statistics. */
+
+ tsk_load = CPU_RC_LOAD_SCALE * (tsk->last_slice - tsk->time_slice)
+ + (CPU_RC_LOAD_SCALE / 2);
+ if (base > CPU_RC_SPREAD_PERIOD)
+ tsk_load = CPU_RC_SPREAD_PERIOD * tsk_load / base;
+
+ last = cr->stat[cpu].timestamp;
+ update = now - last;
+ if (update > CPU_RC_SPREAD_PERIOD)
+ resgrp_load = 0; /* statistics data obsolete. */
+ else
+ resgrp_load = cr->stat[cpu].load
+ * (CPU_RC_SPREAD_PERIOD - update);
+
+ cr->stat[cpu].timestamp = now;
+ cr->stat[cpu].load = (resgrp_load + tsk_load) / CPU_RC_SPREAD_PERIOD;
+out:
+ put_cpu();
+}
Index: linux-2.6.17-rc3/kernel/sched.c
===================================================================
--- linux-2.6.17-rc3.orig/kernel/sched.c
+++ linux-2.6.17-rc3/kernel/sched.c
@@ -43,6 +43,7 @@
#include <linux/rcupdate.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
+#include <linux/cpu_rc.h>
#include <linux/percpu.h>
#include <linux/kthread.h>
#include <linux/seq_file.h>
@@ -1377,6 +1378,7 @@ int fastcall wake_up_state(task_t *p, un
void fastcall sched_fork(task_t *p, int clone_flags)
{
int cpu = get_cpu();
+ unsigned long now;
#ifdef CONFIG_SMP
cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
@@ -1416,6 +1418,9 @@ void fastcall sched_fork(task_t *p, int
p->first_time_slice = 1;
current->time_slice >>= 1;
p->timestamp = sched_clock();
+ now = jiffies;
+ cpu_rc_record_allocation(current, current->time_slice, now);
+ cpu_rc_record_allocation(p, p->time_slice, now);
if (unlikely(!current->time_slice)) {
/*
* This case is rare, it happens when the parent has only
@@ -1533,6 +1538,8 @@ void fastcall sched_exit(task_t *p)
p->parent->time_slice += p->time_slice;
if (unlikely(p->parent->time_slice > task_timeslice(p)))
p->parent->time_slice = task_timeslice(p);
+ cpu_rc_record_allocation(p->parent,
+ p->parent->time_slice, jiffies);
}
if (p->sleep_avg < p->parent->sleep_avg)
p->parent->sleep_avg = p->parent->sleep_avg /
@@ -2617,6 +2624,7 @@ void scheduler_tick(void)
runqueue_t *rq = this_rq();
task_t *p = current;
unsigned long long now = sched_clock();
+ unsigned long jnow;
update_cpu_clock(p, rq, now);
@@ -2651,6 +2659,9 @@ void scheduler_tick(void)
p->time_slice = task_timeslice(p);
p->first_time_slice = 0;
set_tsk_need_resched(p);
+#ifdef CONFIG_CPU_RC
+ /* XXX need accounting even for rt_task? */
+#endif
/* put it at the end of the queue: */
requeue_task(p, rq->active);
@@ -2660,9 +2671,12 @@ void scheduler_tick(void)
if (!--p->time_slice) {
dequeue_task(p, rq->active);
set_tsk_need_resched(p);
+ jnow = jiffies;
+ cpu_rc_account(p, jnow);
p->prio = effective_prio(p);
p->time_slice = task_timeslice(p);
p->first_time_slice = 0;
+ cpu_rc_record_allocation(p, p->time_slice, jnow);
if (!rq->expired_timestamp)
rq->expired_timestamp = jiffies;
Index: linux-2.6.17-rc3/kernel/exit.c
===================================================================
--- linux-2.6.17-rc3.orig/kernel/exit.c
+++ linux-2.6.17-rc3/kernel/exit.c
@@ -36,6 +36,7 @@
#include <linux/compat.h>
#include <linux/pipe_fs_i.h>
#include <linux/res_group.h>
+#include <linux/cpu_rc.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -852,6 +853,7 @@ fastcall NORET_TYPE void do_exit(long co
int group_dead;
profile_task_exit(tsk);
+ cpu_rc_account(tsk, jiffies);
WARN_ON(atomic_read(&tsk->fs_excl));
-
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