Commit 5713f35c authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
Browse files

proc: read kernel cpu stat pointer once 

Help gcc generate better code:

	$ ./scripts/bloat-o-meter ../vmlinux-000 ../vmlinux-001
	add/remove: 2/2 grow/shrink: 0/1 up/down: 92/-142 (-50)
	Function                                     old     new   delta
	get_iowait_time.isra                           -      46     +46
	get_idle_time.isra                             -      46     +46
	show_stat                                   1489    1477     -12
	get_iowait_time                               65       -     -65
	get_idle_time                                 65       -     -65

Link: http://lkml.kernel.org/r/20190114195907.GA9680@avx2


Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 867aaccf

fs/proc/stat.c

+32 −28
Original line number Diff line number Diff line
@@ -23,21 +23,21 @@ 


#ifdef arch_idle_time



static u64 get_idle_time(int cpu)

static u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)

{

	u64 idle;



	idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];

	idle = kcs->cpustat[CPUTIME_IDLE];

	if (cpu_online(cpu) && !nr_iowait_cpu(cpu))

		idle += arch_idle_time(cpu);

	return idle;

}



static u64 get_iowait_time(int cpu)

static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)

{

	u64 iowait;



	iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];

	iowait = kcs->cpustat[CPUTIME_IOWAIT];

	if (cpu_online(cpu) && nr_iowait_cpu(cpu))

		iowait += arch_idle_time(cpu);

	return iowait;
@@ -45,7 +45,7 @@ static u64 get_iowait_time(int cpu) 


#else



static u64 get_idle_time(int cpu)

static u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)

{

	u64 idle, idle_usecs = -1ULL;
@@ -54,14 +54,14 @@ static u64 get_idle_time(int cpu) 


	if (idle_usecs == -1ULL)

		/* !NO_HZ or cpu offline so we can rely on cpustat.idle */

		idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];

		idle = kcs->cpustat[CPUTIME_IDLE];

	else

		idle = idle_usecs * NSEC_PER_USEC;



	return idle;

}



static u64 get_iowait_time(int cpu)

static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)

{

	u64 iowait, iowait_usecs = -1ULL;
@@ -70,7 +70,7 @@ static u64 get_iowait_time(int cpu) 


	if (iowait_usecs == -1ULL)

		/* !NO_HZ or cpu offline so we can rely on cpustat.iowait */

		iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];

		iowait = kcs->cpustat[CPUTIME_IOWAIT];

	else

		iowait = iowait_usecs * NSEC_PER_USEC;
@@ -95,16 +95,18 @@ static int show_stat(struct seq_file *p, void *v) 
	getboottime64(&boottime);



	for_each_possible_cpu(i) {

		user += kcpustat_cpu(i).cpustat[CPUTIME_USER];

		nice += kcpustat_cpu(i).cpustat[CPUTIME_NICE];

		system += kcpustat_cpu(i).cpustat[CPUTIME_SYSTEM];

		idle += get_idle_time(i);

		iowait += get_iowait_time(i);

		irq += kcpustat_cpu(i).cpustat[CPUTIME_IRQ];

		softirq += kcpustat_cpu(i).cpustat[CPUTIME_SOFTIRQ];

		steal += kcpustat_cpu(i).cpustat[CPUTIME_STEAL];

		guest += kcpustat_cpu(i).cpustat[CPUTIME_GUEST];

		guest_nice += kcpustat_cpu(i).cpustat[CPUTIME_GUEST_NICE];

		struct kernel_cpustat *kcs = &kcpustat_cpu(i);



		user += kcs->cpustat[CPUTIME_USER];

		nice += kcs->cpustat[CPUTIME_NICE];

		system += kcs->cpustat[CPUTIME_SYSTEM];

		idle += get_idle_time(kcs, i);

		iowait += get_iowait_time(kcs, i);

		irq += kcs->cpustat[CPUTIME_IRQ];

		softirq += kcs->cpustat[CPUTIME_SOFTIRQ];

		steal += kcs->cpustat[CPUTIME_STEAL];

		guest += kcs->cpustat[CPUTIME_GUEST];

		guest_nice += kcs->cpustat[CPUTIME_GUEST_NICE];

		sum += kstat_cpu_irqs_sum(i);

		sum += arch_irq_stat_cpu(i);
@@ -130,17 +132,19 @@ static int show_stat(struct seq_file *p, void *v) 
	seq_putc(p, '\n');



	for_each_online_cpu(i) {

		struct kernel_cpustat *kcs = &kcpustat_cpu(i);



		/* Copy values here to work around gcc-2.95.3, gcc-2.96 */

		user = kcpustat_cpu(i).cpustat[CPUTIME_USER];

		nice = kcpustat_cpu(i).cpustat[CPUTIME_NICE];

		system = kcpustat_cpu(i).cpustat[CPUTIME_SYSTEM];

		idle = get_idle_time(i);

		iowait = get_iowait_time(i);

		irq = kcpustat_cpu(i).cpustat[CPUTIME_IRQ];

		softirq = kcpustat_cpu(i).cpustat[CPUTIME_SOFTIRQ];

		steal = kcpustat_cpu(i).cpustat[CPUTIME_STEAL];

		guest = kcpustat_cpu(i).cpustat[CPUTIME_GUEST];

		guest_nice = kcpustat_cpu(i).cpustat[CPUTIME_GUEST_NICE];

		user = kcs->cpustat[CPUTIME_USER];

		nice = kcs->cpustat[CPUTIME_NICE];

		system = kcs->cpustat[CPUTIME_SYSTEM];

		idle = get_idle_time(kcs, i);

		iowait = get_iowait_time(kcs, i);

		irq = kcs->cpustat[CPUTIME_IRQ];

		softirq = kcs->cpustat[CPUTIME_SOFTIRQ];

		steal = kcs->cpustat[CPUTIME_STEAL];

		guest = kcs->cpustat[CPUTIME_GUEST];

		guest_nice = kcs->cpustat[CPUTIME_GUEST_NICE];

		seq_printf(p, "cpu%d", i);

		seq_put_decimal_ull(p, " ", nsec_to_clock_t(user));

		seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));

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