providing and using destroy method

Author: dderjoel

Changelog

@@ -1,5 +1,7 @@
 version 2.1.2-beta
 	- fix build errors
+	- fix segfault caused by incorrect syscall in timer.c
+	- adding `destroy` method to cleanly free/unmap data
 
 version 2.1.1 (2023-06-29)
 	- fix package-lock.json file

lib/src/measuresuite.c

@@ -131,6 +131,7 @@ int ms_get_cycles(measuresuite_t ms, size_t **dest, size_t idx) {
 int ms_terminate(measuresuite_t ms) {
   if (ms_unload_all(ms) // unload all the loaded functions
       || end_random(ms) // free random data spot
+      || end_timer(ms)  // free all timer related data
   ) {
     return 1;
   }

lib/src/timer.c

@@ -178,6 +178,9 @@ static uint64_t measuresuite_time_rdtscp() {
  */
 int init_timer(struct measuresuite *ms) {
 
+  // init timer struct
+  memset(&ms->timer, 0, sizeof(ms->timer));
+
   // try to initialize
   init_fdperf(ms);
 
@@ -192,6 +195,23 @@ int init_timer(struct measuresuite *ms) {
   return 0;
 }
 
+/**
+ * This function checks if we used PMC and will then free the mmapped region
+ */
+int end_timer(struct measuresuite *ms) {
+
+  if (ms->timer.fdperf == -1) {
+    // we've used RDTSCP, nothing to be done
+    return 0;
+  }
+  // otherwise we used pmc
+  if (munmap(ms->timer.buf, sysconf(_SC_PAGESIZE)) == 0) {
+    return 0;
+  }
+  perror("munmap of timer buffer (pmc) failed.");
+  return 1;
+}
+
 void start_timer(struct measuresuite *ms, uint64_t *start) {
   // we need to reset the PMC if we are using them.
   if (ms->timer.timer_function == measuresuite_time_pmc) {

lib/src/timer.h

@@ -21,6 +21,7 @@
 #include <stdint.h>
 
 int init_timer(struct measuresuite *ms);
+int end_timer(struct measuresuite *ms);
 void start_timer(struct measuresuite *ms, uint64_t *start);
 uint64_t stop_timer(struct measuresuite *ms, uint64_t start);
 

ts/src/binding/binding.c

@@ -66,6 +66,9 @@ napi_value Init(napi_env env, napi_value exports) {
   // measure(batchSize: number, numBatches: number): string;
   register_function(env, exports, measure, "measure");
 
+  // destroy(): number;
+  register_function(env, exports, destroy, "destroy");
+
   return exports;
 }
 

ts/src/binding/helper.c

@@ -16,8 +16,8 @@
 
 #include "helper.h"
 // NOLINTNEXTLINE (must declare hint as a valid callback for NODE_API)
-void finalise(napi_env env, void *finalize_data, void *finalize_hint) {
-  if (ms_terminate((measuresuite_t)finalize_data)) {
+void finalise(napi_env env, void *finalise_data, void *finalize_hint) {
+  if (ms_terminate((measuresuite_t)finalise_data)) {
     if (napi_throw_error(env, NULL, "measure_end didnt work.") != napi_ok) {
       fprintf(stderr, "Unable to throw error.\n");
     }

ts/src/binding/helper.h

@@ -22,7 +22,7 @@
 #include <stdio.h>
 #include <string.h>
 
-void finalise(napi_env env, void *finalize_data, void *finalize_hint);
+void finalise(napi_env env, void *finalise_data, void *finalize_hint);
 
 void throw_error_return_void(napi_env env, const char *msg);
 

ts/src/binding/other_functions.c

@@ -58,12 +58,26 @@ void init(napi_env env, napi_callback_info info) {
   }
 
   // save the measuresuite_t handle in as the instance data. and set the
-  // finalise callback to call measure end
+  // finalise callback to call ms_teminate
   if (napi_set_instance_data(env, ms, &finalise, NULL) != napi_ok) {
     return throw_error_return_void(
         env, "Unable to set instance data / finalize_cb.");
   }
 }
+napi_value destroy(napi_env env, napi_callback_info info) {
+  void *instance_data = NULL;
+  if (napi_get_instance_data(env, &instance_data) != napi_ok) {
+    return throw_and_return_napi_val(env, "Unable to get instance data.");
+  }
+
+  measuresuite_t ms = (measuresuite_t)instance_data;
+  if (ms_terminate(ms)) {
+    throw_and_return_napi_val(env, "Unable to destroy measuresuite instance.");
+  }
+  napi_value napi_result = NULL;
+  napi_create_int32(env, 0, &napi_result);
+  return napi_result;
+}
 
 napi_value binding_set_bounds(napi_env env, napi_callback_info info) {
   // getting back the instance

ts/src/binding/other_functions.h

@@ -20,5 +20,6 @@
 void init(napi_env env, napi_callback_info info);
 napi_value binding_set_bounds(napi_env env, napi_callback_info info);
 napi_value measure(napi_env env, napi_callback_info info);
+napi_value destroy(napi_env env, napi_callback_info info);
 
 #endif /* OTHER_FUNCTIONS_H */

ts/src/measuresuite-native-module.d.ts

@@ -32,4 +32,5 @@ declare module "measuresuite-native-module" {
   function set_bounds(bounds: BigUint64Array): void;
 
   function measure(batchSize: number, numBatches: number): string;
+  function destroy(): number;
 }

ts/src/measuresuite.ts

@@ -43,6 +43,7 @@ export const native_ms = {
   set_bounds: ms.set_bounds,
 
   measure: ms.measure,
+  destroy: ms.destroy,
 };
 
 export class Measuresuite {
@@ -96,6 +97,10 @@ export class Measuresuite {
     this.ft2load.set("SHARED_OBJECT", ms.load_shared_object_file);
   }
 
+  public destroy(): number {
+    return ms.destroy();
+  }
+
   // mapping tables
   private ft2load = new Map<FunctionType, (filename: string, symbol: string) => void>();