diff --git a/src/donar.c b/src/donar.c
index 85905f9..041a318 100644
--- a/src/donar.c
+++ b/src/donar.c
@@ -15,8 +15,11 @@ int main(int argc, char** argv) {
     struct donar_params dp;
     donar_init_params (&dp);
 
-    while ((dp.opt = getopt(argc, argv, "cse:r:o:a:bh")) != -1) {
+    while ((dp.opt = getopt(argc, argv, "vcse:r:o:a:bh")) != -1) {
       switch(dp.opt) {
+      case 'v':
+        dp.verbose++;
+        break;
       case 's':
         dp.is_server = 1;
         break;
diff --git a/src/donar_client.c b/src/donar_client.c
index ee4e994..99f9e85 100644
--- a/src/donar_client.c
+++ b/src/donar_client.c
@@ -76,7 +76,7 @@ void donar_client(struct donar_client_ctx* ctx, struct donar_params* dp) {
     .is_healing = dp->is_healing
   };
 
-  evt_core_init (&(ctx->evts));
+  evt_core_init (&(ctx->evts), dp->verbose);
   init_algo(&ctx->evts, &algo, dp->algo, &ap);
   socks5_init (&ctx->evts);
   init_socks5_sinks(ctx);
diff --git a/src/donar_init.h b/src/donar_init.h
index 72595c5..6d83551 100644
--- a/src/donar_init.h
+++ b/src/donar_init.h
@@ -7,7 +7,7 @@
 #include "packet.h"
 
 struct donar_params {
-  int opt, is_server, is_client, is_waiting_bootstrap, is_healing, errored;
+  int opt, is_server, is_client, is_waiting_bootstrap, is_healing, errored, verbose;
   char *port, *onion_file, *algo;
   GPtrArray *remote_ports, *exposed_ports;
 };
diff --git a/src/donar_server.c b/src/donar_server.c
index 310f2b5..48e309f 100644
--- a/src/donar_server.c
+++ b/src/donar_server.c
@@ -58,7 +58,7 @@ void donar_server(struct donar_server_ctx* ctx,  struct donar_params* dp) {
     .is_healing = dp->is_healing
   };
 
-  evt_core_init (&(ctx->evts));
+  evt_core_init (&(ctx->evts), dp->verbose);
   init_algo(&ctx->evts, &algo, dp->algo, &ap);
   evt_core_add_cat (&(ctx->evts), &(algo.on_tcp_co));
   evt_core_add_cat (&(ctx->evts), &(algo.on_udp_read));
diff --git a/src/evt_core.c b/src/evt_core.c
index 1e7b728..498679e 100644
--- a/src/evt_core.c
+++ b/src/evt_core.c
@@ -20,13 +20,13 @@ void free_cat(void* vcat) {
   free(cat);
 }
 
-void evt_core_init(struct evt_core_ctx* ctx) {
+void evt_core_init(struct evt_core_ctx* ctx, uint8_t verbose) {
   ctx->epollfd = epoll_create1(0);
   if (ctx->epollfd == -1) {
     perror("Failed to create epoll file descriptor epoll_create1");
     exit(EXIT_FAILURE);
   }
-
+  ctx->verbose = verbose;
   ctx->catlist = g_hash_table_new_full(g_str_hash, g_str_equal,NULL, free_cat);
   ctx->socklist = g_hash_table_new_full(g_int_hash, g_int_equal, NULL, free_fdinfo);
   ctx->urltofd = g_hash_table_new_full(g_str_hash, g_str_equal, NULL, NULL);
@@ -65,7 +65,7 @@ void evt_core_add_cat(struct evt_core_ctx* ctx, struct evt_core_cat* cat) {
 }
 
 void evt_core_mv_fd(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo, struct evt_core_cat* to_cat) {
-  printf("Moving fd=%d from cat=%s to cat=%s\n",fdinfo->fd, fdinfo->cat->name, to_cat->name);
+  if (ctx->verbose) printf("Moving fd=%d from cat=%s to cat=%s\n",fdinfo->fd, fdinfo->cat->name, to_cat->name);
 
   // 1. Update old category
   for (int i = 0; i < fdinfo->cat->socklist->len; i++) {
@@ -130,7 +130,7 @@ struct evt_core_fdinfo* evt_core_add_fd(struct evt_core_ctx* ctx, struct evt_cor
 
   // 5. Add file descriptor to epoll
   add_fd_to_epoll(ctx->epollfd, user_data->fd, cat->flags);
-  printf("Added fd=%d with url=%s in cat=%s\n", fdinfo->fd, fdinfo->url, fdinfo->cat->name);
+  if (ctx->verbose) printf("Added fd=%d with url=%s in cat=%s\n", fdinfo->fd, fdinfo->url, fdinfo->cat->name);
 
   // 6. Ensure that events arrived before epoll registering are handled
   fdinfo->cat->cb(ctx, fdinfo);
@@ -145,7 +145,7 @@ struct evt_core_cat* evt_core_rm_fd(struct evt_core_ctx* ctx, int fd) {
   struct evt_core_fdinfo* fdinfo = g_hash_table_lookup (ctx->socklist, &fd);
   if (fdinfo == NULL) return NULL;
   cat = fdinfo->cat;
-  printf("Closing fd=%d from cat=%s\n",fdinfo->fd, fdinfo->cat->name);
+  if (ctx->verbose) printf("Closing fd=%d from cat=%s\n",fdinfo->fd, fdinfo->cat->name);
 
   // 2. Update category
   for (int i = 0; i < cat->socklist->len; i++) {
@@ -176,6 +176,8 @@ void evt_core_loop(struct evt_core_ctx* ctx) {
   struct epoll_event current_event, events[EVT_CORE_MAX_EVENTS];
   struct evt_core_fdinfo* fdinfo;
   struct evt_core_cat* cat;
+  clock_t start, end;
+  double elapsed_in_cb;
 
   printf("--- Start main loop\n");
   int num_fd, n = 0;
@@ -231,12 +233,18 @@ void evt_core_loop(struct evt_core_ctx* ctx) {
         fprintf(stderr, "Ignoring file descriptor %d as it is not registered. This is a bug.\n", events[n].data.fd);
         continue;
       }
+      if (ctx->verbose) start = clock();
       while(fdinfo->cat->cb(ctx, fdinfo) == 0);
-
+      if (ctx->verbose) {
+        end = clock();
+        elapsed_in_cb = ((double) (end - start)) / CLOCKS_PER_SEC;
+        printf("%s cb took %f seconds to execute.\n", fdinfo->url, elapsed_in_cb);
+      }
     }
   }
 
   evt_core_free(ctx);
+  return;
 }
 
 struct evt_core_fdinfo* evt_core_get_from_fd(struct evt_core_ctx* ctx, int fd) {
diff --git a/src/evt_core.h b/src/evt_core.h
index 0b5b2ac..4f3c39b 100644
--- a/src/evt_core.h
+++ b/src/evt_core.h
@@ -30,6 +30,7 @@ struct evt_core_cat {
 
 struct evt_core_ctx {
   int epollfd;
+  uint8_t verbose;
   GHashTable* catlist;  // name -> category
   GHashTable* socklist; // fd -> category
   GHashTable* urltofd;  // url -> fd, like "tcp:127.0.0.1:7500"
@@ -43,7 +44,7 @@ struct evt_core_fdinfo {
   evt_core_free_app_ctx free_other;
 };
 
-void evt_core_init(struct evt_core_ctx* ctx);
+void evt_core_init(struct evt_core_ctx* ctx, uint8_t verbose);
 void evt_core_add_cat(struct evt_core_ctx* ctx, struct evt_core_cat* cat);
 void evt_core_mv_fd(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo, struct evt_core_cat* to_cat);
 void evt_core_mv_fd2(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo, char* to_cat);
diff --git a/src/meas_lat.c b/src/meas_lat.c
index 679cab4..972be87 100644
--- a/src/meas_lat.c
+++ b/src/meas_lat.c
@@ -9,7 +9,7 @@
 #include "socks5.h"
 
 struct measlat_ctx {
-  int count, size, interval;
+  int count, size, interval, verbose;
   char *host, *port, *transport;
 };
 
@@ -213,7 +213,7 @@ int on_socks5_failed_measlat(struct evt_core_ctx* ctx, struct evt_core_fdinfo* f
 void register_categories(struct evt_core_ctx* evts, struct measlat_ctx* mctx) {
   struct evt_core_cat template = {0};
   template.app_ctx = mctx;
-  evt_core_init(evts);
+  evt_core_init(evts, mctx->verbose);
 
   template.cb = on_timer;
   template.name = "timer";
@@ -282,8 +282,11 @@ int main(int argc, char** argv) {
   struct evt_core_ctx evts = {0};
 
   // 1. Parse parameters
-  while ((opt = getopt(argc, argv, "h:p:c:s:i:t:")) != -1) {
+  while ((opt = getopt(argc, argv, "vh:p:c:s:i:t:")) != -1) {
       switch(opt) {
+      case 'v':
+        mctx.verbose++;
+        break;
       case 'h': // host
         mctx.host = optarg;
         break;
diff --git a/src/tor_echo.c b/src/tor_echo.c
index 2436b4c..a612a60 100644
--- a/src/tor_echo.c
+++ b/src/tor_echo.c
@@ -110,7 +110,7 @@ int main(int argc, char** argv) {
     .flags = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLRDHUP,
     .socklist = NULL
   };
-  evt_core_init(&evts);
+  evt_core_init(&evts, 0);
   evt_core_add_cat(&evts, &tcp_co);
   evt_core_add_cat(&evts, &tcp_all);
   printf("--- Categories created\n");
diff --git a/src/udp_echo.c b/src/udp_echo.c
index 3fd6256..71d2caf 100644
--- a/src/udp_echo.c
+++ b/src/udp_echo.c
@@ -41,7 +41,7 @@ int main(int argc, char** argv) {
   while ((opt = getopt(argc, argv, "p:v")) != -1) {
       switch(opt) {
       case 'v':
-        verbose = 1;
+        verbose++;
         break;
       case 'p':
         port = optarg;
@@ -61,7 +61,7 @@ int main(int argc, char** argv) {
     .flags = EPOLLIN | EPOLLET,
     .socklist = NULL
   };
-  evt_core_init(&evts);
+  evt_core_init(&evts, verbose);
   evt_core_add_cat(&evts, &udp_read);
 
   // 3. Register UDP socket