[PATCH 43/70] cpufreq: interactive: add io_is_busy interface

From: BÃlint Czobor
Date: Tue Oct 27 2015 - 13:33:18 EST


From: Lianwei Wang <lian-wei.wang@xxxxxxxxxxxx>

Previously the idle time returned from get_cpu_idle_time_us included the
iowait time. So the iowait time was always calculated as idle time.

But now the idle time returned from get_cpu_idle_time_us does not include
the iowait time anymore because of below commit which cause the iowait time
always calculated as busy time:
6beea0c nohz: Fix update_ts_time_stat idle accounting

Add the io_is_busy interface, as does the ondemand governor, and let the user
configure the iowait time as busy or idle through the io_is_busy sysfs
interface.

By default, io_is_busy is disabled.

[toddpoynor@xxxxxxxxxx: minor updates]
Change-Id: If7d70ff864c43bc9c8d7fd7cfc66f930d339f9b4
Signed-off-by: Lianwei Wang <lian-wei.wang@xxxxxxxxxxxx>
Signed-off-by: Todd Poynor <toddpoynor@xxxxxxxxxx>
Signed-off-by: BÃlint Czobor <czoborbalint@xxxxxxxxx>
---
drivers/cpufreq/cpufreq_interactive.c | 66 ++++++++++++++++++++++++++++++++-
1 file changed, 64 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index 620b46c..7c734fa 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -30,6 +30,7 @@
#include <linux/workqueue.h>
#include <linux/kthread.h>
#include <linux/slab.h>
+#include <linux/kernel_stat.h>
#include <asm/cputime.h>

#define CREATE_TRACE_POINTS
@@ -114,6 +115,8 @@ static u64 boostpulse_endtime;
#define DEFAULT_TIMER_SLACK (4 * DEFAULT_TIMER_RATE)
static int timer_slack_val = DEFAULT_TIMER_SLACK;

+static bool io_is_busy;
+
static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
unsigned int event);

@@ -127,6 +130,42 @@ struct cpufreq_governor cpufreq_gov_interactive = {
.owner = THIS_MODULE,
};

+static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
+ cputime64_t *wall)
+{
+ u64 idle_time;
+ u64 cur_wall_time;
+ u64 busy_time;
+
+ cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
+
+ busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
+ busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
+ busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
+ busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
+ busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
+ busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
+
+ idle_time = cur_wall_time - busy_time;
+ if (wall)
+ *wall = jiffies_to_usecs(cur_wall_time);
+
+ return jiffies_to_usecs(idle_time);
+}
+
+static inline cputime64_t get_cpu_idle_time(unsigned int cpu,
+ cputime64_t *wall)
+{
+ u64 idle_time = get_cpu_idle_time_us(cpu, wall);
+
+ if (idle_time == -1ULL)
+ idle_time = get_cpu_idle_time_jiffy(cpu, wall);
+ else if (!io_is_busy)
+ idle_time += get_cpu_iowait_time_us(cpu, wall);
+
+ return idle_time;
+}
+
static void cpufreq_interactive_timer_resched(
struct cpufreq_interactive_cpuinfo *pcpu)
{
@@ -141,7 +180,7 @@ static void cpufreq_interactive_timer_resched(

spin_lock_irqsave(&pcpu->load_lock, flags);
pcpu->time_in_idle =
- get_cpu_idle_time_us(smp_processor_id(),
+ get_cpu_idle_time(smp_processor_id(),
&pcpu->time_in_idle_timestamp);
pcpu->cputime_speedadj = 0;
pcpu->cputime_speedadj_timestamp = pcpu->time_in_idle_timestamp;
@@ -278,7 +317,7 @@ static u64 update_load(int cpu)
unsigned int delta_time;
u64 active_time;

- now_idle = get_cpu_idle_time_us(cpu, &now);
+ now_idle = get_cpu_idle_time(cpu, &now);
delta_idle = (unsigned int)(now_idle - pcpu->time_in_idle);
delta_time = (unsigned int)(now - pcpu->time_in_idle_timestamp);
active_time = delta_time - delta_idle;
@@ -924,6 +963,28 @@ static ssize_t store_boostpulse_duration(

define_one_global_rw(boostpulse_duration);

+static ssize_t show_io_is_busy(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ return sprintf(buf, "%u\n", io_is_busy);
+}
+
+static ssize_t store_io_is_busy(struct kobject *kobj,
+ struct attribute *attr, const char *buf, size_t count)
+{
+ int ret;
+ unsigned long val;
+
+ ret = kstrtoul(buf, 0, &val);
+ if (ret < 0)
+ return ret;
+ io_is_busy = val;
+ return count;
+}
+
+static struct global_attr io_is_busy_attr = __ATTR(io_is_busy, 0644,
+ show_io_is_busy, store_io_is_busy);
+
static struct attribute *interactive_attributes[] = {
&target_loads_attr.attr,
&above_hispeed_delay_attr.attr,
@@ -935,6 +996,7 @@ static struct attribute *interactive_attributes[] = {
&boost.attr,
&boostpulse.attr,
&boostpulse_duration.attr,
+ &io_is_busy_attr.attr,
NULL,
};

--
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/