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>
diff --git a/src/vlib/threads.c b/src/vlib/threads.c
index 713e192..3994afc 100644
--- a/src/vlib/threads.c
+++ b/src/vlib/threads.c
@@ -179,7 +179,9 @@
u32 n_vlib_mains = 1;
u32 first_index = 1;
u32 i;
- uword *avail_cpu;
+ pid_t pid;
+ uword *avail_cpu, *affinity_cpu;
+ uword n_cpus;
u32 stats_num_worker_threads_dir_index;
stats_num_worker_threads_dir_index =
@@ -190,16 +192,39 @@
tm->cpu_core_bitmap = os_get_online_cpu_core_bitmap ();
tm->cpu_socket_bitmap = os_get_online_cpu_node_bitmap ();
+ /* get bitmap of active cpu cores vpp has affinity to */
+ pid = getpid ();
+ tm->cpu_affinity_bitmap = os_get_cpu_affinity_bitmap (pid);
+
+ /* if fetching affinity fails, return online cpu core bmp */
+ if (tm->cpu_affinity_bitmap == 0)
+ tm->cpu_affinity_bitmap = os_get_online_cpu_core_bitmap ();
+
avail_cpu = clib_bitmap_dup (tm->cpu_core_bitmap);
+ affinity_cpu = clib_bitmap_dup (tm->cpu_affinity_bitmap);
/* skip cores */
+ n_cpus = clib_bitmap_count_set_bits (avail_cpu);
+ if (tm->skip_cores >= n_cpus)
+ return clib_error_return (0, "skip-core greater than available cpus");
+ n_cpus = clib_bitmap_count_set_bits (affinity_cpu);
+ if (tm->skip_cores >= n_cpus)
+ return clib_error_return (0, "skip-core greater than affinity cpus");
+
for (i = 0; i < tm->skip_cores; i++)
{
- uword c = clib_bitmap_first_set (avail_cpu);
+ uword c;
+ c = clib_bitmap_first_set (avail_cpu);
if (c == ~0)
return clib_error_return (0, "no available cpus to skip");
avail_cpu = clib_bitmap_set (avail_cpu, c, 0);
+
+ c = clib_bitmap_first_set (affinity_cpu);
+ if (c == ~0)
+ return clib_error_return (0, "no available env cpus to skip");
+
+ affinity_cpu = clib_bitmap_set (affinity_cpu, c, 0);
}
/* grab cpu for main thread */
@@ -209,6 +234,17 @@
return clib_error_return (0, "cpu %u is not available to be used"
" for the main thread", tm->main_lcore);
avail_cpu = clib_bitmap_set (avail_cpu, tm->main_lcore, 0);
+ affinity_cpu = clib_bitmap_set (affinity_cpu, tm->main_lcore, 0);
+ }
+ /* if auto enabled, grab first cpu vpp has affinity to for main thread */
+ else if (tm->use_main_core_auto)
+ {
+ uword c = clib_bitmap_first_set (affinity_cpu);
+ if (c != ~0)
+ tm->main_lcore = c;
+
+ avail_cpu = clib_bitmap_set (avail_cpu, tm->main_lcore, 0);
+ affinity_cpu = clib_bitmap_set (affinity_cpu, tm->main_lcore, 0);
}
/* assume that there is socket 0 only if there is no data from sysfs */
@@ -289,13 +325,23 @@
}
else
{
+ /* for automatic pinning, use cpu affinity list */
+ uword n_env_cpu = 0;
+ n_env_cpu = clib_bitmap_count_set_bits (affinity_cpu);
+
+ if (n_env_cpu < tr->count)
+ return clib_error_return (0,
+ "no available cpus to be used for"
+ " the '%s' thread #%u",
+ tr->name, n_env_cpu);
+
for (j = 0; j < tr->count; j++)
{
/* Do not use CPU 0 by default - leave it to the host and IRQs */
- uword avail_c0 = clib_bitmap_get (avail_cpu, 0);
- avail_cpu = clib_bitmap_set (avail_cpu, 0, 0);
+ uword avail_c0 = clib_bitmap_get (affinity_cpu, 0);
+ affinity_cpu = clib_bitmap_set (affinity_cpu, 0, 0);
- uword c = clib_bitmap_first_set (avail_cpu);
+ uword c = clib_bitmap_first_set (affinity_cpu);
/* Use CPU 0 as a last resort */
if (c == ~0 && avail_c0)
{
@@ -309,14 +355,15 @@
" the '%s' thread #%u",
tr->name, tr->count);
- avail_cpu = clib_bitmap_set (avail_cpu, 0, avail_c0);
- avail_cpu = clib_bitmap_set (avail_cpu, c, 0);
+ affinity_cpu = clib_bitmap_set (affinity_cpu, 0, avail_c0);
+ affinity_cpu = clib_bitmap_set (affinity_cpu, c, 0);
tr->coremask = clib_bitmap_set (tr->coremask, c, 1);
}
}
}
clib_bitmap_free (avail_cpu);
+ clib_bitmap_free (affinity_cpu);
tm->n_vlib_mains = n_vlib_mains;
vlib_stats_set_gauge (stats_num_worker_threads_dir_index, n_vlib_mains - 1);
@@ -1118,6 +1165,7 @@
tm->sched_policy = ~0;
tm->sched_priority = ~0;
tm->main_lcore = ~0;
+ tm->use_main_core_auto = 0;
tr = tm->next;
@@ -1133,6 +1181,8 @@
tm->use_pthreads = 1;
else if (unformat (input, "thread-prefix %v", &tm->thread_prefix))
;
+ else if (unformat (input, "main-core auto"))
+ tm->use_main_core_auto = 1;
else if (unformat (input, "main-core %u", &tm->main_lcore))
;
else if (unformat (input, "skip-cores %u", &tm->skip_cores))
@@ -1191,6 +1241,13 @@
break;
}
+ if (tm->main_lcore != ~0 && tm->use_main_core_auto)
+ {
+ return clib_error_return (
+ 0, "cannot set both 'main-core %u' and 'main-core auto'",
+ tm->main_lcore);
+ }
+
if (tm->sched_priority != ~0)
{
if (tm->sched_policy == SCHED_FIFO || tm->sched_policy == SCHED_RR)
diff --git a/src/vlib/threads.h b/src/vlib/threads.h
index ac0c1d5..3072d0e 100644
--- a/src/vlib/threads.h
+++ b/src/vlib/threads.h
@@ -255,6 +255,8 @@
int use_pthreads;
+ int use_main_core_auto;
+
/* Number of vlib_main / vnet_main clones */
u32 n_vlib_mains;
@@ -282,6 +284,9 @@
/* Bitmap of available CPU sockets (NUMA nodes) */
uword *cpu_socket_bitmap;
+ /* Bitmap of CPU affinity for VPP process */
+ uword *cpu_affinity_bitmap;
+
/* Worker handoff queues */
vlib_frame_queue_main_t *frame_queue_mains;
diff --git a/src/vppinfra/unix-misc.c b/src/vppinfra/unix-misc.c
index e0591ff..4dbc5ce 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 @@
}
__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 651f9bb..3ad57b0 100644
--- a/src/vppinfra/unix.h
+++ b/src/vppinfra/unix.h
@@ -56,6 +56,9 @@
/* 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 ();