examples/vm_power: show warning when more than 64 cores

When using VM power manager app on systems with more than 64 cores,
app could not run even though user does not use cores 64 or higher.
The problem happens only in that case, in which case it will result
in an undefined behaviour.

Thefere, this patch allows the user to run the app on a system with more
than 64 cores, warning the user not to use cores higher than 64 in the VM(s).

Add new known issue where VM power manager app may not work
in a system with more than 64 cores, in release notes.

Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Tested-by: Marvin Liu <yong.liu@intel.com>
Acked-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>

diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
index 7b62085..a39c714 100644 (file)
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -837,3 +837,27 @@ Devices bound to igb_uio with VT-d enabled do not work on Linux* kernel 3.15-3.1
 +--------------------------------+--------------------------------------------------------------------------------------+
 | Driver/Module                  | igb_uio module                                                                       |
 +--------------------------------+--------------------------------------------------------------------------------------+
+
+VM power manager may not work on systems with more than 64 cores
+----------------------------------------------------------------
+
++--------------------------------+--------------------------------------------------------------------------------------+
+| Title                          | VM power manager may not work on systems with more than 64 cores                     |
+|                                |                                                                                      |
++================================+======================================================================================+
+| Description                    | When using VM power manager on a system with more than 64 cores,                     |
+|                                | VM(s) should not use cores 64 or higher.                                             |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Implication                    | VM power manager should not be used with VM(s) that are using cores 64 or above.     |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Resolution/ Workaround         | Do not use cores 64 or above.                                                        |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Affected Environment/ Platform | Platforms with more than 64 cores.                                                   |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Driver/Module                  | VM power manager application                                                         |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+

diff --git a/examples/vm_power_manager/channel_manager.c b/examples/vm_power_manager/channel_manager.c
index 7d892e2..35ff40a 100644 (file)
--- a/examples/vm_power_manager/channel_manager.c
+++ b/examples/vm_power_manager/channel_manager.c
@@ -764,12 +764,11 @@ channel_manager_init(const char *path)
        }
        global_n_host_cpus = (unsigned)n_cpus;
 
-       if (global_n_host_cpus > CHANNEL_CMDS_MAX_CPUS) {
-               RTE_LOG(ERR, CHANNEL_MANAGER, "The number of host CPUs(%u) exceeds the "
-                               "maximum of %u\n", global_n_host_cpus, CHANNEL_CMDS_MAX_CPUS);
-               goto error;
-
-       }
+       if (global_n_host_cpus > CHANNEL_CMDS_MAX_CPUS)
+               RTE_LOG(WARNING, CHANNEL_MANAGER, "The number of host CPUs(%u) exceeds the "
+                               "maximum of %u. No cores over %u should be used.\n",
+                               global_n_host_cpus, CHANNEL_CMDS_MAX_CPUS,
+                               CHANNEL_CMDS_MAX_CPUS - 1);
 
        return 0;
 error: