common/numa: Skip the DPDK thread when setting NUMA affinity

The CPU affinity of the DPDK thread has been set during DPDK initialization.
Do not modify the DPDK affinity when setting NUMA affinity.

Signed-off-by: Chunsong Feng <fengchunsong@huawei.com>
Reviewed-by: luo rixin <luorixin@huawei.com>
Reviewed-by: Han Fengzhe  <hanfengzhe@hisilicon.com>

diff --git a/src/common/numa.cc b/src/common/numa.cc
index 87fde6e68af8a68247228b56f1f9c728e2310b93..7af8247f2a531165b3aa8fd6140cf4cafcceafda 100644 (file)
--- a/src/common/numa.cc
+++ b/src/common/numa.cc
@@ -156,6 +156,32 @@ static int easy_readdir(const std::string& dir, std::set<std::string> *out)
   return 0;
 }
 
+static std::string get_task_comm(pid_t tid)
+{
+  static const char* comm_fmt = "/proc/self/task/%d/comm";
+  char comm_name[strlen(comm_fmt) + 8];
+  snprintf(comm_name, sizeof(comm_name), comm_fmt, tid);
+  int fd = open(comm_name, O_CLOEXEC | O_RDONLY);
+  if (fd == -1) {
+    return "";
+  }
+  // see linux/sched.h
+  static constexpr int TASK_COMM_LEN = 16;
+  char name[TASK_COMM_LEN];
+  ssize_t n = safe_read(fd, name, sizeof(name));
+  close(fd);
+  if (n < 0) {
+    return "";
+  }
+  assert(n <= sizeof(name));
+  if (name[n - 1] == '\n') {
+    name[n - 1] = '\0';
+  } else {
+    name[n] = '\0';
+  }
+  return name;
+}
+
 int set_cpu_affinity_all_threads(size_t cpu_set_size, cpu_set_t *cpu_set)
 {
   // first set my affinity
@@ -179,6 +205,14 @@ int set_cpu_affinity_all_threads(size_t cpu_set_size, cpu_set_t *cpu_set)
       if (!tid) {
        continue;  // wtf
       }
+      #ifdef HAVE_DPDK
+      std::string thread_name = get_task_comm(tid);
+      static const char *dpdk_worker_name = "lcore-worker";
+      if (!thread_name.compare(0, strlen(dpdk_worker_name), dpdk_worker_name)) {
+       // ignore dpdk reactor thread, as it takes case of numa by itself
+        continue;
+      }
+      #endif
       r = sched_setaffinity(tid, cpu_set_size, cpu_set);
       if (r < 0) {
        return -errno;