vlib: improve automatic core pinning

Type: feature

Auto core pinning now fetches vpp cpu affinity list
using pthread api. This enables us to do core-pinning in
environments where the host cpu list does not necessarily align
with cpus available to vpp

Change-Id: Ife8c2a2351c08c5c6c4fdf7c729eeff2697bc39a
Signed-off-by: hsandid <halsandi@cisco.com>

2 files changed, 34 insertions, 0 deletions

diff --git a/src/vppinfra/unix-misc.c b/src/vppinfra/unix-misc.c
index e0591ff4604..4dbc5ce98ce 100644
--- a/src/vppinfra/unix-misc.c
+++ b/src/vppinfra/unix-misc.c
@@ -46,6 +46,7 @@
 
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/syscall.h>
 #include <sys/uio.h>		/* writev */
 #include <fcntl.h>
 #include <stdio.h>		/* for sprintf */
@@ -275,6 +276,36 @@ os_get_online_cpu_core_bitmap ()
 }
 
 __clib_export clib_bitmap_t *
+os_get_cpu_affinity_bitmap (int pid)
+{
+#if __linux
+  int index, ret;
+  cpu_set_t cpuset;
+  uword *affinity_cpus;
+
+  clib_bitmap_alloc (affinity_cpus, sizeof (cpu_set_t));
+  clib_bitmap_zero (affinity_cpus);
+
+  __CPU_ZERO_S (sizeof (cpu_set_t), &cpuset);
+
+  ret = syscall (SYS_sched_getaffinity, 0, sizeof (cpu_set_t), &cpuset);
+
+  if (ret < 0)
+    {
+      clib_bitmap_free (affinity_cpus);
+      return 0;
+    }
+
+  for (index = 0; index < sizeof (cpu_set_t); index++)
+    if (__CPU_ISSET_S (index, sizeof (cpu_set_t), &cpuset))
+      clib_bitmap_set (affinity_cpus, index, 1);
+  return affinity_cpus;
+#else
+  return 0;
+#endif
+}
+
+__clib_export clib_bitmap_t *
 os_get_online_cpu_node_bitmap ()
 {
 #if __linux__
diff --git a/src/vppinfra/unix.h b/src/vppinfra/unix.h
index 651f9bb99e0..3ad57b05e72 100644
--- a/src/vppinfra/unix.h
+++ b/src/vppinfra/unix.h
@@ -56,6 +56,9 @@ clib_error_t *unix_proc_file_contents (char *file, u8 ** result);
 /* Retrieve bitmap of online cpu cures */
 clib_bitmap_t *os_get_online_cpu_core_bitmap ();
 
+/* Retrieve bitmap of cpus vpp has affinity to */
+clib_bitmap_t *os_get_cpu_affinity_bitmap (int pid);
+
 /* Retrieve bitmap of online cpu nodes (sockets) */
 clib_bitmap_t *os_get_online_cpu_node_bitmap ();