added MCA parameter to limit number of ptls used

This commit was SVN r3490.

src/mca/ptl/mx/ptl_mx.h

@@ -28,6 +28,7 @@ struct mca_ptl_mx_component_t {
     int mx_debug;                          /**< debug level */
     uint32_t mx_filter;                    /**< filter assigned to application */
     uint32_t mx_num_ptls;                  /**< number of MX NICs available to app */
+    uint32_t mx_max_ptls;                  /**< max number  of MX NICs to use */
     struct mca_ptl_mx_module_t** mx_ptls;  /**< array of available PTL moduless */
     ompi_free_list_t mx_send_frags;        /**< free list of mx send fragments */
     ompi_free_list_t mx_recv_frags;        /**< free list of mx recv fragments */

src/mca/ptl/mx/ptl_mx_component.c

@@ -102,6 +102,8 @@ int mca_ptl_mx_component_open(void)
         mca_ptl_mx_param_register_int("free_list_max", -1);
     mca_ptl_mx_component.mx_free_list_inc =
         mca_ptl_mx_param_register_int("free_list_inc", 256);
+    mca_ptl_mx_component.mx_max_ptls = 
+        (uint32_t)mca_ptl_mx_param_register_int("num_nics", -1);
     mca_ptl_mx_module.super.ptl_exclusivity =
         mca_ptl_mx_param_register_int("exclusivity", 0);
     mca_ptl_mx_module.super.ptl_first_frag_size =
@@ -154,7 +156,7 @@ mca_ptl_base_module_t** mca_ptl_mx_component_init(
     mca_ptl_base_module_t** ptls;
     *num_ptls = 0;
     *allow_multi_user_threads = true;
-    *have_hidden_threads = OMPI_HAVE_THREADS;
+    *have_hidden_threads = true; /* MX driver/callbacks are multi-threaded */
 
     ompi_free_list_init(&mca_ptl_mx_component.mx_send_frags, 
         sizeof(mca_ptl_mx_send_frag_t),

src/mca/ptl/mx/ptl_mx_module.c

@@ -56,6 +56,10 @@ int mca_ptl_mx_module_init(void)
         return OMPI_ERR_INIT;
     }
 
+    /* check for limit on number of ptls */
+    if(mca_ptl_mx_component.mx_num_ptls > mca_ptl_mx_component.mx_max_ptls)
+       mca_ptl_mx_component.mx_num_ptls = mca_ptl_mx_component.mx_max_ptls;
+
     /* allocate an array of pointers to ptls */
     mca_ptl_mx_component.mx_ptls = (mca_ptl_mx_module_t**)malloc(
         sizeof(mca_ptl_mx_module_t*) * mca_ptl_mx_component.mx_num_ptls);