How to get possible CPUS in Ubuntu 14.04 or 16.04
I have a process which is pinned on core 1. I have written the below function to get the affinity.
count_cpu_cores()
{
long int n_cores;
n_cores = sysconf(_SC_NPROCESSORS_CONF);
if (n_cores > 0) {
cpu_set_t *set = CPU_ALLOC(n_cores);
if (set) {
size_t size = CPU_ALLOC_SIZE(n_cores);
if (!sched_getaffinity(146244, size, set)) {
printf("enter sched affinityn");
n_cores = CPU_COUNT_S(size, set);
}
CPU_FREE(set);
}
printf("n_cores-%d",n_cores);
}
When i print ncores , it give me value of 32 which is incorrect. On further debugging i find that
sched_getaffinity return EINVAL as it is expecting the greater size. Now when i hardcode n_cores
to be 144 which is the number in possible cpus as below. I get the correct value of the number of
CPUS that is 1. How can i fix this problem in my program without hardcoding ?
sdn@dell33:~$ cd /sys/devices/system/cpu
sdn@dell33:/sys/devices/system/cpu$ ls
cpu0 cpu12 cpu16 cpu2 cpu23 cpu27 cpu30 cpu6 cpufreq kernel_max online uevent
cpu1 cpu13 cpu17 cpu20 cpu24 cpu28 cpu31 cpu7 cpuidle microcode possible vulnerabilities
cpu10 cpu14 cpu18 cpu21 cpu25 cpu29 cpu4 cpu8 intel_pstate modalias power
cpu11 cpu15 cpu19 cpu22 cpu26 cpu3 cpu5 cpu9 isolated offline present
sdn@dell33:/sys/devices/system/cpu$ cat possible
0-143
sdn@dell33:/sys/devices/system/cpu$ cat kernel_max
511
14.04 16.04 cpu coreutils cpuinfo
asked Jan 16 at 4:13
Vincent AVincent A
11
add a comment |
I have a process which is pinned on core 1. I have written the below function to get the affinity.
count_cpu_cores()
{
long int n_cores;
n_cores = sysconf(_SC_NPROCESSORS_CONF);
if (n_cores > 0) {
cpu_set_t *set = CPU_ALLOC(n_cores);
if (set) {
size_t size = CPU_ALLOC_SIZE(n_cores);
if (!sched_getaffinity(146244, size, set)) {
printf("enter sched affinityn");
n_cores = CPU_COUNT_S(size, set);
}
CPU_FREE(set);
}
printf("n_cores-%d",n_cores);
}
When i print ncores , it give me value of 32 which is incorrect. On further debugging i find that
sched_getaffinity return EINVAL as it is expecting the greater size. Now when i hardcode n_cores
to be 144 which is the number in possible cpus as below. I get the correct value of the number of
CPUS that is 1. How can i fix this problem in my program without hardcoding ?
sdn@dell33:~$ cd /sys/devices/system/cpu
sdn@dell33:/sys/devices/system/cpu$ ls
cpu0 cpu12 cpu16 cpu2 cpu23 cpu27 cpu30 cpu6 cpufreq kernel_max online uevent
cpu1 cpu13 cpu17 cpu20 cpu24 cpu28 cpu31 cpu7 cpuidle microcode possible vulnerabilities
cpu10 cpu14 cpu18 cpu21 cpu25 cpu29 cpu4 cpu8 intel_pstate modalias power
cpu11 cpu15 cpu19 cpu22 cpu26 cpu3 cpu5 cpu9 isolated offline present
sdn@dell33:/sys/devices/system/cpu$ cat possible
0-143
sdn@dell33:/sys/devices/system/cpu$ cat kernel_max
511
14.04 16.04 cpu coreutils cpuinfo
asked Jan 16 at 4:13
Vincent AVincent A
11
add a comment |
I have a process which is pinned on core 1. I have written the below function to get the affinity.
count_cpu_cores()
{
long int n_cores;
n_cores = sysconf(_SC_NPROCESSORS_CONF);
if (n_cores > 0) {
cpu_set_t *set = CPU_ALLOC(n_cores);
if (set) {
size_t size = CPU_ALLOC_SIZE(n_cores);
if (!sched_getaffinity(146244, size, set)) {
printf("enter sched affinityn");
n_cores = CPU_COUNT_S(size, set);
}
CPU_FREE(set);
}
printf("n_cores-%d",n_cores);
}
When i print ncores , it give me value of 32 which is incorrect. On further debugging i find that
sched_getaffinity return EINVAL as it is expecting the greater size. Now when i hardcode n_cores
to be 144 which is the number in possible cpus as below. I get the correct value of the number of
CPUS that is 1. How can i fix this problem in my program without hardcoding ?
sdn@dell33:~$ cd /sys/devices/system/cpu
sdn@dell33:/sys/devices/system/cpu$ ls
cpu0 cpu12 cpu16 cpu2 cpu23 cpu27 cpu30 cpu6 cpufreq kernel_max online uevent
cpu1 cpu13 cpu17 cpu20 cpu24 cpu28 cpu31 cpu7 cpuidle microcode possible vulnerabilities
cpu10 cpu14 cpu18 cpu21 cpu25 cpu29 cpu4 cpu8 intel_pstate modalias power
cpu11 cpu15 cpu19 cpu22 cpu26 cpu3 cpu5 cpu9 isolated offline present
sdn@dell33:/sys/devices/system/cpu$ cat possible
0-143
sdn@dell33:/sys/devices/system/cpu$ cat kernel_max
511
14.04 16.04 cpu coreutils cpuinfo
asked Jan 16 at 4:13
Vincent AVincent A
11
I have a process which is pinned on core 1. I have written the below function to get the affinity.
count_cpu_cores()
{
long int n_cores;
n_cores = sysconf(_SC_NPROCESSORS_CONF);
if (n_cores > 0) {
cpu_set_t *set = CPU_ALLOC(n_cores);
if (set) {
size_t size = CPU_ALLOC_SIZE(n_cores);
if (!sched_getaffinity(146244, size, set)) {
printf("enter sched affinityn");
n_cores = CPU_COUNT_S(size, set);
}
CPU_FREE(set);
}
printf("n_cores-%d",n_cores);
}
When i print ncores , it give me value of 32 which is incorrect. On further debugging i find that
sched_getaffinity return EINVAL as it is expecting the greater size. Now when i hardcode n_cores
to be 144 which is the number in possible cpus as below. I get the correct value of the number of
CPUS that is 1. How can i fix this problem in my program without hardcoding ?
sdn@dell33:~$ cd /sys/devices/system/cpu
sdn@dell33:/sys/devices/system/cpu$ ls
cpu0 cpu12 cpu16 cpu2 cpu23 cpu27 cpu30 cpu6 cpufreq kernel_max online uevent
cpu1 cpu13 cpu17 cpu20 cpu24 cpu28 cpu31 cpu7 cpuidle microcode possible vulnerabilities
cpu10 cpu14 cpu18 cpu21 cpu25 cpu29 cpu4 cpu8 intel_pstate modalias power
cpu11 cpu15 cpu19 cpu22 cpu26 cpu3 cpu5 cpu9 isolated offline present
sdn@dell33:/sys/devices/system/cpu$ cat possible
0-143
sdn@dell33:/sys/devices/system/cpu$ cat kernel_max
511
14.04 16.04 cpu coreutils cpuinfo
14.04 16.04 cpu coreutils cpuinfo
asked Jan 16 at 4:13
Vincent AVincent A
11
asked Jan 16 at 4:13
Vincent AVincent A
11
asked Jan 16 at 4:13
Vincent AVincent A
11
asked Jan 16 at 4:13
Vincent AVincent A
11
asked Jan 16 at 4:13
Vincent AVincent A
11
11
add a comment |
add a comment |
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