small fixies for alltoall running oob

Author: JuliaRS

src_c/IMB_mem_info.h

@@ -55,6 +55,6 @@ Header file newly introduced in IMB 3.1
 #define CACHE_LINE_SIZE  64 /* default last level cache line size (Bytes) */
 
 #define MEM_UNIT 1073741824 /* Units for memory usage sizes */
-#define MAX_MEM_USAGE  1  /* default max. memory (in units MEM_UNIT Bytes) used for message buffers */
+#define MAX_MEM_USAGE  2  /* default max. memory (in units MEM_UNIT Bytes) used for message buffers */
 
 #endif

src_c/IMB_output.c

@@ -342,7 +342,11 @@ Input variables:
                 break;
 
             case SAMPLE_FAILED_INT_OVERFLOW:
-                sprintf(aux_string + offset, " int-overflow.; The production rank*size caused int overflow for given sample");
+#ifdef MPI1
+                sprintf(aux_string + offset, " int-overflow; The production rank*size=%u caused int overflow for given sample; use flag \"-data_type double\"", size*(c_info->w_num_procs));
+#else
+                sprintf(aux_string + offset, " int-overflow; The production rank*size=%u caused int overflow for given sample", size*(c_info->w_num_procs));
+#endif
                 break;
             case SAMPLE_FAILED_TIME_OUT:
                 aux_string[offset] = '\0';