Allowing modern GPU configrations to properly run PTXPLUS.

There are several problems with this:

1) To get proper occupancy, based on register file usage, you must querry ptxas with
   the sm version that corresponds to the register usage in the config file. To enable this,
   a new config option has been added that determines what sm version you pass to ptxas to compute reg-usage.
   This configuration option is always required in the gpgpusim.config file
2) If you are running PTXPLUS with a modern card (i.e. volta/pascal), you need ptxas from CUDA 9.1.
   However since PTXPLUS only supports sm_13 - you need a version of CUDA where cudaobjectdump
   supports sm_1x. This ended at CUDA 5 - and PTXPLUS requires CUDA 4.2. Therefore, to run PTXPLUS
   on a modern card, you need CUDA 4.2 + modern CUDA installed. To fascilitate this, a new envronment
   varaible is added and the setup envrionment script prints an appropraite warning if you are using a newer CUDA.

We have tried to make this as fail-proof as possible - and die appropraitely when something is wrong.

1 files changed, 14 insertions, 4 deletions

diff --git a/src/cuda-sim/ptx_loader.cc b/src/cuda-sim/ptx_loader.cc
index 6c1b595..99174cf 100644
--- a/src/cuda-sim/ptx_loader.cc
+++ b/src/cuda-sim/ptx_loader.cc
@@ -54,6 +54,7 @@ extern int ptxinfo_debug;
 extern FILE *ptxinfo_in;
 
 static bool g_save_embedded_ptx;
+static int g_occupancy_sm_number;
 bool g_keep_intermediate_files;
 bool m_ptx_save_converted_ptxplus;
 
@@ -71,6 +72,10 @@ void ptx_reg_options(option_parser_t opp)
                 &m_ptx_save_converted_ptxplus,
                 "Saved converted ptxplus to a file",
                 "0");
+   option_parser_register(opp, "-gpgpu_occupancy_sm_number", OPT_INT32, &g_occupancy_sm_number,
+                "The SM number to pass to ptxas when getting register usage for computing GPU occupancy."
+                "This parameter is required in the config.",
+                "0");
 }
 
 void print_ptx_file( const char *p, unsigned source_num, const char *filename )
@@ -287,7 +292,7 @@ void fix_duplicate_errors(char fname2[1024]) {
 	}
 }
 
-void gpgpu_ptxinfo_load_from_string( const char *p_for_info, unsigned source_num, unsigned sm_version )
+void gpgpu_ptxinfo_load_from_string( const char *p_for_info, unsigned source_num )
 {
     char fname[1024];
     snprintf(fname,1024,"_ptx_XXXXXX");
@@ -321,12 +326,17 @@ void gpgpu_ptxinfo_load_from_string( const char *p_for_info, unsigned source_num
     extra_flags[0]=0;
 
 #if CUDART_VERSION >= 3000
-    if (sm_version == 0) sm_version = 20;
+    if ( g_occupancy_sm_number == 0 ) {
+        printf( "gpgpusim.config must specify the sm version for the GPU that you use to compute occupancy.\n"
+                "The register file size is specifically tied to the sm version used to querry ptxas for register usage."
+                "A register size/SM mismatch may result in occupancy differences." );
+        exit(1);
+    }
     extern bool g_cdp_enabled;
     if(!g_cdp_enabled)
-        snprintf(extra_flags,1024,"--gpu-name=sm_%u",sm_version);
+        snprintf(extra_flags,1024,"--gpu-name=sm_%u", g_occupancy_sm_number);
     else
-        snprintf(extra_flags,1024,"--compile-only --gpu-name=sm_%u",sm_version);
+        snprintf(extra_flags,1024,"--compile-only --gpu-name=sm_%u",g_occupancy_sm_number);
 #endif
 
     snprintf(commandline,1024,"$CUDA_INSTALL_PATH/bin/ptxas %s -v %s --output-file  /dev/null 2> %s",