[difftest] add "success" field in perf.json

It indicates "online dpi" finishes normally , rather than terminated due to timeout.

difftest/dpi_common/src/util.rs

@@ -1,9 +1,10 @@
 //! utility functions
 
-pub fn write_perf_json(cycle: u64) {
+pub fn write_perf_json(cycle: u64, success: bool) {
   let mut content = String::new();
   content += "{\n";
-  content += &format!("    \"total_cycles\": {cycle}\n");
+  content += &format!("    \"total_cycles\": {cycle},\n");
+  content += &format!("    \"success\": {success}\n");
   content += "}\n";
 
   match std::fs::write("perf.json", &content) {

difftest/dpi_t1/src/dpi.rs

@@ -231,7 +231,9 @@ unsafe extern "C" fn t1_cosim_init() {
 
 #[no_mangle]
 unsafe extern "C" fn t1_cosim_final() {
-  dpi_common::util::write_perf_json(crate::get_t());
+  TARGET.with(|driver| {
+    dpi_common::util::write_perf_json(crate::get_t(), driver.success);
+  })
 }
 
 /// evaluate at every 1024 cycles, return reason = 0 to continue simulation,

difftest/dpi_t1/src/drive.rs

@@ -103,6 +103,7 @@ pub(crate) struct Driver {
   scope: SvScope,
 
   dump_control: DumpControl,
+  pub(crate) success: bool,
 
   pub(crate) dlen: u32,
 
@@ -132,6 +133,7 @@ impl Driver {
 
       scope,
       dump_control,
+      success: false,
 
       dlen: args.dlen,
       timeout: args.timeout,
@@ -261,6 +263,7 @@ impl Driver {
               get_t(),
               se.pc
             );
+            self.success = true;
             IssueData { meta: ISSUE_EXIT, ..Default::default() }
           } else {
             self.spike_runner.commit_queue.pop_back();

difftest/dpi_t1rocket/src/dpi.rs

@@ -284,7 +284,9 @@ unsafe extern "C" fn t1rocket_cosim_init() {
 
 #[no_mangle]
 unsafe extern "C" fn t1rocket_cosim_final() {
-  dpi_common::util::write_perf_json(crate::get_t());
+  TARGET.with(|driver| {
+    dpi_common::util::write_perf_json(crate::get_t(), driver.success);
+  });
 }
 
 /// evaluate at every 1024 cycles, return reason = 0 to continue simulation,

difftest/dpi_t1rocket/src/drive.rs

@@ -121,6 +121,7 @@ pub(crate) struct Driver {
   shadow_mem: ShadowMem,
 
   pub(crate) quit: bool,
+  pub(crate) success: bool,
 }
 
 impl Driver {
@@ -142,6 +143,7 @@ impl Driver {
       shadow_mem,
 
       quit: false,
+      success: false,
     }
   }
 
@@ -305,6 +307,7 @@ impl Driver {
       let exit_data_slice = data[..4].try_into().expect("slice with incorrect length");
       if u32::from_le_bytes(exit_data_slice) == EXIT_CODE {
         info!("driver is ready to quit");
+        self.success = true;
         self.quit = true;
       }
     }