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authorLinus Torvalds <torvalds@linux-foundation.org>2010-05-18 08:27:54 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-18 08:27:54 -0700
commitb8ae30ee26d379db436b0b8c8c3ff1b52f69e5d1 (patch)
tree506aa0b4bdbf90f61e7e9261c7db90aa1452dcce /drivers
parent4d7b4ac22fbec1a03206c6cde353f2fd6942f828 (diff)
parent9c6f7e43b4e02c161b53e97ba913855246876c61 (diff)
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (49 commits) stop_machine: Move local variable closer to the usage site in cpu_stop_cpu_callback() sched, wait: Use wrapper functions sched: Remove a stale comment ondemand: Make the iowait-is-busy time a sysfs tunable ondemand: Solve a big performance issue by counting IOWAIT time as busy sched: Intoduce get_cpu_iowait_time_us() sched: Eliminate the ts->idle_lastupdate field sched: Fold updating of the last_update_time_info into update_ts_time_stats() sched: Update the idle statistics in get_cpu_idle_time_us() sched: Introduce a function to update the idle statistics sched: Add a comment to get_cpu_idle_time_us() cpu_stop: add dummy implementation for UP sched: Remove rq argument to the tracepoints rcu: need barrier() in UP synchronize_sched_expedited() sched: correctly place paranioa memory barriers in synchronize_sched_expedited() sched: kill paranoia check in synchronize_sched_expedited() sched: replace migration_thread with cpu_stop stop_machine: reimplement using cpu_stop cpu_stop: implement stop_cpu[s]() sched: Fix select_idle_sibling() logic in select_task_rq_fair() ...
Diffstat (limited to 'drivers')
-rw-r--r--drivers/cpufreq/cpufreq_ondemand.c75
-rw-r--r--drivers/xen/manage.c14
2 files changed, 75 insertions, 14 deletions
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index bd444dc93cf2..8e9dbdc6c700 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -73,6 +73,7 @@ enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE};
struct cpu_dbs_info_s {
cputime64_t prev_cpu_idle;
+ cputime64_t prev_cpu_iowait;
cputime64_t prev_cpu_wall;
cputime64_t prev_cpu_nice;
struct cpufreq_policy *cur_policy;
@@ -108,6 +109,7 @@ static struct dbs_tuners {
unsigned int down_differential;
unsigned int ignore_nice;
unsigned int powersave_bias;
+ unsigned int io_is_busy;
} dbs_tuners_ins = {
.up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
.down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL,
@@ -148,6 +150,16 @@ static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
return idle_time;
}
+static inline cputime64_t get_cpu_iowait_time(unsigned int cpu, cputime64_t *wall)
+{
+ u64 iowait_time = get_cpu_iowait_time_us(cpu, wall);
+
+ if (iowait_time == -1ULL)
+ return 0;
+
+ return iowait_time;
+}
+
/*
* Find right freq to be set now with powersave_bias on.
* Returns the freq_hi to be used right now and will set freq_hi_jiffies,
@@ -249,6 +261,7 @@ static ssize_t show_##file_name \
return sprintf(buf, "%u\n", dbs_tuners_ins.object); \
}
show_one(sampling_rate, sampling_rate);
+show_one(io_is_busy, io_is_busy);
show_one(up_threshold, up_threshold);
show_one(ignore_nice_load, ignore_nice);
show_one(powersave_bias, powersave_bias);
@@ -299,6 +312,23 @@ static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b,
return count;
}
+static ssize_t store_io_is_busy(struct kobject *a, struct attribute *b,
+ const char *buf, size_t count)
+{
+ unsigned int input;
+ int ret;
+
+ ret = sscanf(buf, "%u", &input);
+ if (ret != 1)
+ return -EINVAL;
+
+ mutex_lock(&dbs_mutex);
+ dbs_tuners_ins.io_is_busy = !!input;
+ mutex_unlock(&dbs_mutex);
+
+ return count;
+}
+
static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
const char *buf, size_t count)
{
@@ -381,6 +411,7 @@ static struct global_attr _name = \
__ATTR(_name, 0644, show_##_name, store_##_name)
define_one_rw(sampling_rate);
+define_one_rw(io_is_busy);
define_one_rw(up_threshold);
define_one_rw(ignore_nice_load);
define_one_rw(powersave_bias);
@@ -392,6 +423,7 @@ static struct attribute *dbs_attributes[] = {
&up_threshold.attr,
&ignore_nice_load.attr,
&powersave_bias.attr,
+ &io_is_busy.attr,
NULL
};
@@ -470,14 +502,15 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
for_each_cpu(j, policy->cpus) {
struct cpu_dbs_info_s *j_dbs_info;
- cputime64_t cur_wall_time, cur_idle_time;
- unsigned int idle_time, wall_time;
+ cputime64_t cur_wall_time, cur_idle_time, cur_iowait_time;
+ unsigned int idle_time, wall_time, iowait_time;
unsigned int load, load_freq;
int freq_avg;
j_dbs_info = &per_cpu(od_cpu_dbs_info, j);
cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
+ cur_iowait_time = get_cpu_iowait_time(j, &cur_wall_time);
wall_time = (unsigned int) cputime64_sub(cur_wall_time,
j_dbs_info->prev_cpu_wall);
@@ -487,6 +520,10 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
j_dbs_info->prev_cpu_idle);
j_dbs_info->prev_cpu_idle = cur_idle_time;
+ iowait_time = (unsigned int) cputime64_sub(cur_iowait_time,
+ j_dbs_info->prev_cpu_iowait);
+ j_dbs_info->prev_cpu_iowait = cur_iowait_time;
+
if (dbs_tuners_ins.ignore_nice) {
cputime64_t cur_nice;
unsigned long cur_nice_jiffies;
@@ -504,6 +541,16 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
idle_time += jiffies_to_usecs(cur_nice_jiffies);
}
+ /*
+ * For the purpose of ondemand, waiting for disk IO is an
+ * indication that you're performance critical, and not that
+ * the system is actually idle. So subtract the iowait time
+ * from the cpu idle time.
+ */
+
+ if (dbs_tuners_ins.io_is_busy && idle_time >= iowait_time)
+ idle_time -= iowait_time;
+
if (unlikely(!wall_time || wall_time < idle_time))
continue;
@@ -617,6 +664,29 @@ static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
cancel_delayed_work_sync(&dbs_info->work);
}
+/*
+ * Not all CPUs want IO time to be accounted as busy; this dependson how
+ * efficient idling at a higher frequency/voltage is.
+ * Pavel Machek says this is not so for various generations of AMD and old
+ * Intel systems.
+ * Mike Chan (androidlcom) calis this is also not true for ARM.
+ * Because of this, whitelist specific known (series) of CPUs by default, and
+ * leave all others up to the user.
+ */
+static int should_io_be_busy(void)
+{
+#if defined(CONFIG_X86)
+ /*
+ * For Intel, Core 2 (model 15) andl later have an efficient idle.
+ */
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
+ boot_cpu_data.x86 == 6 &&
+ boot_cpu_data.x86_model >= 15)
+ return 1;
+#endif
+ return 0;
+}
+
static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
unsigned int event)
{
@@ -679,6 +749,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
dbs_tuners_ins.sampling_rate =
max(min_sampling_rate,
latency * LATENCY_MULTIPLIER);
+ dbs_tuners_ins.io_is_busy = should_io_be_busy();
}
mutex_unlock(&dbs_mutex);
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index 2ac4440e7b08..8943b8ccee1a 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -80,12 +80,6 @@ static void do_suspend(void)
shutting_down = SHUTDOWN_SUSPEND;
- err = stop_machine_create();
- if (err) {
- printk(KERN_ERR "xen suspend: failed to setup stop_machine %d\n", err);
- goto out;
- }
-
#ifdef CONFIG_PREEMPT
/* If the kernel is preemptible, we need to freeze all the processes
to prevent them from being in the middle of a pagetable update
@@ -93,7 +87,7 @@ static void do_suspend(void)
err = freeze_processes();
if (err) {
printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
- goto out_destroy_sm;
+ goto out;
}
#endif
@@ -136,12 +130,8 @@ out_resume:
out_thaw:
#ifdef CONFIG_PREEMPT
thaw_processes();
-
-out_destroy_sm:
-#endif
- stop_machine_destroy();
-
out:
+#endif
shutting_down = SHUTDOWN_INVALID;
}
#endif /* CONFIG_PM_SLEEP */