CPU Affinity Not Working in RHEL8 with DPDK 20.05

[Rashi Agarwal]

Hi DPDK Community,

I am facing an issue where CPU affinity is not working as expected in RHEL8 
with DPDK 20.05, while it works fine in RHEL7.
Problem Statement:
      *  When running my program with numactl -C4,5 ./testRTE on RHEL7, the 
worker threads correctly bind to the assigned cores.
      *  However, on RHEL8, the worker threads always bind to core 1, ignoring 
the specified CPU set.

Environment Details:

  *   DPDK Version: 20.05.0
  *   OS: RHEL8 (Issue) | RHEL7 (Works Fine)
  *   CPU Affinity Tool: numactl -C
Sample Program:  Attached
Observations:

  *   In RHEL7, worker threads correctly bind to cores specified using numactl 
-C.
  *   In RHEL8, the threads always bind to core 1, ignoring the CPU set.
  *   Could DPDK be overriding the CPU affinity in RHEL8?
Questions:

  1.  Is there any known change in CPU affinity handling between RHEL7 and 
RHEL8 affecting DPDK?
  2.  Does DPDK override thread affinity when rte_eal_init() is called?
  3.  Is there any workaround or EAL flag to ensure that CPU affinity is 
respected?
Any insights or suggestions would be greatly appreciated.
Thanks,
Rashi Agarwal.

#include <iostream>
#include "stdlib.h"
#include <fstream>
#include <string>
#include "unistd.h"
#include "time.h"
#include "math.h"
#include <pthread.h>
#include <csignal>

#include <rte_common.h>
#include <rte_eal.h>
#include <rte_ring.h>
#include <rte_ring_core.h>


using namespace std;
int keepRunning=1;

void signal_handler(int signum) 
{
    std::cout << "\nSignal (" << signum << ") received. Exiting..." << 
std::endl;
    keepRunning = 0;
}

void init_dpdk()
{
    /* DPDK initialization */
    int instId = 12;
    char procName[50] = {0} ;
    char filePrefix[50] = {0} ;
    sprintf(procName, "ipp-dpdk-opt-%d", instId) ;
    sprintf(filePrefix, "--file-prefix=ipp-inst-%d", instId) ;
    int dpdk_argc = 8; char *dpdk_argv[] = { procName, "-c", "0x2", 
"--no-huge", filePrefix ,"-m","64" , "--log-level=eal,8"};

    int ret = rte_eal_init(dpdk_argc, dpdk_argv);
        if(ret < 0)
    {
        cout << "DPDK initialization: rte_eal_init failed with code "<< ret << 
endl;
        return  ;
    }
        cout << "\n\n\n";

}

void init_ring()
{
        for (int i=0; i<25; i++)
        {
                int size = pow(2,i) ;
                cout << i+1 << " " << size -1 << endl; //" "<< 
rte_ring_get_memsize(size) << endl ;
                char name [50];
                sprintf (name,"test_ring-%d",i);
                rte_ring_create(name, size-1, 0, RING_F_EXACT_SZ);
        }
}

static void* thread_func1(void *arg)
{
        while(keepRunning)
        {
                printf("this is thread1\n");
                sleep(100);
        }
        return NULL;
}

static void* thread_func2(void *arg)
{
        while(keepRunning)
        {
                printf("this is thread2\n");
                sleep(100);
        }
        return NULL;
}

int main() {
        std::cout << "##################### Starting the test ################ 
" << std::endl;

    struct sigaction sig_action;
    sig_action.sa_handler = signal_handler;
    sigemptyset(&sig_action.sa_mask);
    sig_action.sa_flags = 0;
    sigaction(SIGINT, &sig_action, NULL);

        init_dpdk();

        // worker threads initializtion
    pthread_t thread_id1, thread_id2;
    pthread_attr_t thread_attr;
    pthread_attr_init(&thread_attr);

    pthread_create(&thread_id1, &thread_attr, &thread_func1,NULL);
    pthread_setname_np(thread_id1, "WorkerThread1");
    pthread_create(&thread_id2, &thread_attr, &thread_func2,NULL);
    pthread_setname_np(thread_id2, "WorkerThread2");

    while (keepRunning) {
        pause();  
    }

    std::cout << "##################### Edning the test ################ " << 
std::endl;
    pthread_join(thread_id1, NULL);
    pthread_join(thread_id2, NULL);


    return 0;
}