add RTS tuning to haskell_init

apps/ios/SimpleXChat/hs_init.c

@@ -10,16 +10,32 @@
 
 extern void hs_init_with_rtsopts(int * argc, char **argv[]);
 
-void haskell_init(void) {
-    int argc = 5;
-    char *argv[] = {
-        "simplex",
-        "+RTS", // requires `hs_init_with_rtsopts`
-        "-A16m", // chunk size for new allocations
-        "-H64m", // initial heap size
-        "-xn", // non-moving GC
-        0
-    };
+void haskell_init(const char *eventlog, const char *heap_profile) {
+    // setup static arena for bump allocation and passing to RTS
+    char *argv[32] = {0,};
+    int argc = 0; // number of arguments used so far, always stands at the first NULL in argv
+    // common args
+    argv[argc++] = "simplex"; // fake program name
+    argv[argc++] = "+RTS"; // start adding RTS options
+    argv[argc++] = "-T"; // make GC counters available from inside the program
+    argv[argc++] = "-A16m"; // chunk size for new allocations (less frequent GC)
+    argv[argc++] = "-H64m"; // larger heap size on start (faster boot)
+    // argv[argc++] = "-M8G"; // keep memory usage under 8G, collecting more aggressively when approaching it (and crashing sooner rather than taking down the whole system)
+    if (eventlog) {
+        static char ol[1024] = "-ol";
+        (void)strncpy(ol[3], eventlog, sizeof(ol) - 3);
+        argv[argc++] = "-olsimplex.eventlog"; // produce <eventlog> file relative to "current" directory
+        argv[argc++] = "-l-agu"; // collect GC and user events
+    }
+    if (heap_profile) {
+        static char po[1024] = "-po";
+        (void)strncpy(po[3], heap_profile, sizeof(po) - 3);
+        argv[argc++] = po; // produce <heap_profile>.hp relative to "current" directory
+        argv[argc++] = "-hT"; // emit heap profile by closure type
+    }
+    int non_moving_gc = !heap_profile; // not compatible with heap profile
+    if (non_moving_gc) argv[argc++] = "-xn";
+    // wrap args as expected by RTS
     char **pargv = argv;
     hs_init_with_rtsopts(&argc, &pargv);
 }

apps/ios/SimpleXChat/hs_init.h

@@ -9,7 +9,7 @@
 #ifndef hs_init_h
 #define hs_init_h
 
-void haskell_init(void);
+void haskell_init(const char *eventlog, const char *heap_profile);
 
 void haskell_init_nse(void);