diff --git a/examples/sntlc.c b/examples/sntlc.c
index beb6276..2cd3488 100644
--- a/examples/sntlc.c
+++ b/examples/sntlc.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#define __USE_GNU
 #include <stdlib.h>
 #include <stdarg.h>
 #include <sys/types.h>
@@ -12,15 +13,129 @@
 #include <errno.h>
 #include <assert.h>
 #include <time.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <execinfo.h>
+#include <sys/resource.h>
 
 #include <tdata/usrtc.h>
 #include <sexpr/sexp.h>
 #include <sntl/connection.h>
-
+           
 /* define a little bit */
 #define DEFAULT_PORT  13133
-#define CHANNEL_COUNT 1
-#define CLIENT_COUNT 2
+#define CHANNEL_COUNT 4000
+#define CLIENT_COUNT 2000
+#define MESSAGES_PER_SESSION 10
+#define ITERATION_COUNT 10
+
+#define FAILS_ONLY
+//#define SIMPLE_TESTING
+
+static FILE *log_file = NULL;
+
+inline int log_init(const char *file)
+{
+  if(log_file) { 
+    fclose(log_file); 
+  } 
+  log_file = fopen(file, "w");
+  if(!log_file) return EIO;
+  return 0;
+}
+
+inline void log_msg(const char *prefix, const char *data)
+{
+  if(log_file) fprintf(log_file, "[%s]: %s\n", prefix, data);
+}
+ 
+inline void log_begin(const char *data) 
+{
+#ifndef FAILS_ONLY
+  log_msg("BEGIN", data);
+#endif
+}
+
+inline void log_end(const char *data) 
+{
+#ifndef FAILS_ONLY
+  log_msg("END", data);
+#endif
+}
+
+inline void log_info(const char *data) 
+{
+#ifndef FAILS_ONLY
+  log_msg("INFO", data);
+#endif
+}
+
+inline void log_error(const char *data) 
+{
+  log_msg("FAILED", data);
+}
+
+inline void log_assert(const char *info, int rc, int exp) 
+{
+  if(log_file && (rc) != (exp)) {
+    fprintf(log_file, "[FAILED]: %s result: %d, expected: %d\n", info, rc, exp);
+  }
+}
+
+inline void log_close()
+{
+  if(log_file) { 
+    fflush(log_file); 
+    fclose(log_file); 
+  }
+}
+
+inline void log_flush()
+{
+  fflush(log_file); 
+}
+
+void signal_error(int sig, siginfo_t *si, void *ptr)
+{
+    void* error_addr;
+    void* trace[16];
+    int    x;
+    int    trace_size;
+    char** messages;
+
+    fprintf(stderr, "Something is wrong: backtrace: \n");
+    uintptr_t fptr = (uintptr_t)(si->si_addr);
+    fprintf(stderr, "Signal: %d, function pointer: 0x%.12lX \n", sig, fptr);
+    #if __WORDSIZE == 64
+        error_addr = (void*)((ucontext_t*)ptr)->uc_mcontext.gregs[REG_RIP];
+    #else
+        error_addr = (void*)((ucontext_t*)ptr)->uc_mcontext.gregs[REG_EIP];
+    #endif
+
+    trace_size = backtrace(trace, 16);
+    trace[1] = error_addr;
+
+    messages = backtrace_symbols(trace, trace_size);
+    if (messages)
+    {
+        for (x = 1; x < trace_size; x++)
+        {
+          fprintf(stderr, "%s\n", messages[x]);
+        }
+        free(messages);
+    }
+    
+    fprintf(stderr, "end of backtrace\n");
+
+    exit(1);
+}
+
+typedef struct
+{
+  pthread_t **threads;
+  int thread_count;
+  conn_t *co;
+} test_data_t;
 
 /*static*/ sexp_t *make_request(const char *req)
 {
@@ -30,96 +145,160 @@
   return sx;
 }
 
-void *test_send_message(void *ch)
+/*static */int allocate_threads(int count, test_data_t *data)
 {
-  __DBGLINE;
-  chnl_t *chnl = (chnl_t *)ch;
-  char buf[1024];
-  int a = rand() % 100;
-  int b = rand() % 100;
-  sprintf(buf, "(ar-add (%d %d))", a, b);
-  sexp_t *add_request = make_request(buf);
-  sxmsg_t *msg = NULL;
-  int rc = 0;
-  clock_t start = clock();
-  rc = msg_send(chnl, add_request, &msg);
-  clock_t end = clock();
-  double time = (double)(end - start) / CLOCKS_PER_SEC;
-  printf("msg_send execution time: %lf. rc = %d\n", time, rc);
-  assert(rc == a + b);
-  destroy_sexp(add_request);
-  return 0x00;
+  int i = 0;           
+  data->threads = (pthread_t **)malloc(count * sizeof(pthread_t *));
+  for(i = 0; i < count; ++i) {
+    data->threads[i] = (pthread_t *)malloc(sizeof(pthread_t));
+    if(!data->threads) return ENOMEM;
+  }
+  data->thread_count = count;
+  return 0;
+}
+/*static */int deallocate_threads(test_data_t *data)
+{
+  int i = 0;
+  for(i = 0; i < data->thread_count; ++i) {
+    if(!data->threads[i]) return EINVAL;
+    pthread_join(*data->threads[i], NULL);
+    free(data->threads[i]);
+    data->threads[i] = 0;
+  }
+  free(data->threads);
+  data->thread_count = 0;
+  
+  return 0;
 }
 
-void *test_channel(void *ctx)
+void *test_invalid_channel(void *ctx)
 {
+  log_begin("Invalid channel testing");
   conn_t *co = (conn_t *)ctx;
-  printf("Testing channel (%ld)\n", pthread_self());
   chnl_t *channel = NULL;
-  int rc = 0;
-  rc = channel_open(co, &channel, 12);
-  if(rc) {
-    printf("Failed to open channel. rc=%d\n", rc);
+  int rc = 0, i;
+  for(i = 0; i < ITERATION_COUNT || ITERATION_COUNT < 0; ++i) {
+    rc = channel_open(co, &channel, 1);
+    log_assert("channel_open with type 1", rc, EINVAL);
+    // TODO: segmentation fault below 
+    //rc = channel_close(channel);
+    //log_assert("channel_close with type 1", rc, EINVAL);
   }
-  assert(rc == 0);
+  log_end("Invalid channel testing");
+  return 0x00;
+}
+
+void *test_correct_channel(void *ctx)
+{
+  log_begin("Channel testing");
   
-  // test message sending
-  int i;
-  pthread_t threads[CLIENT_COUNT];
-  for(i = 0; i < CLIENT_COUNT; ++i) {
-    if(pthread_create(&(threads[i]), NULL, test_send_message, channel)) {
-      fprintf(stderr, "Error creating thread\n");
-      return 0x00;
-    }
-  }
-  for(i = 0; i < CLIENT_COUNT; ++i) {
-    pthread_join(threads[i], NULL);
-  }
+  conn_t *co = (conn_t *)ctx;
+  chnl_t *channel = NULL;
+  int rc = 0, i, j;
+  char buf[128];
+  time_t start, end;
+  int a, b;
+  sexp_t *add_request = NULL;
+  sxmsg_t *msg = NULL;
+  double exec_time;
   
-  rc = channel_close(channel);
-  if(rc) {
-    printf("Failed to close channel. rc=%d\n", rc);
+  for(j = 0; j < ITERATION_COUNT || ITERATION_COUNT < 0; ++j) {
+    rc = channel_open(co, &channel, 12);
+    log_assert("channel_open with type 12", rc, 0);
+    log_begin("Test messaging");
+    for(i = 0; i < MESSAGES_PER_SESSION; ++i) {
+      a = rand() % 100;
+      b = rand() % 100;
+      sprintf(buf, "(ar-add (%d %d))", a, b);
+      add_request = make_request(buf);
+      time(&start);
+      rc = msg_send(channel, add_request, &msg);
+      time(&end);
+      exec_time = difftime(end, start);
+      sprintf(buf, "rpc execution time: %lf", exec_time);
+      log_info(buf);
+      log_assert("rpc execution", rc, a + b);
+      //destroy_sexp(add_request);
+    }
+    log_end("Test messaging");
+
+//    rc = channel_close(channel);
+//    log_assert("channel_close with type 12", rc, 0);
   }
-  assert(rc == 0);
   
+  log_end("Channel testing");
   return 0x00;
 }
 
-/*static*/ int start_testing(conn_t *co)
+int test_channels(test_data_t *data, int index)
 {
-  printf("---------------===========    Testing...   ===========------------------\n");
-  int i;
-  pthread_t threads[CHANNEL_COUNT];
-  for(i = 0; i < CHANNEL_COUNT; ++i) {
-    if(pthread_create(&(threads[i]), NULL, test_channel, co)) {
-      fprintf(stderr, "Error creating thread\n");
-      return EINVAL;
-    }
+  int rc = 0;  
+  if(index < CLIENT_COUNT) {
+    rc = pthread_create(data->threads[index], NULL, test_correct_channel, data->co);
+  } else {
+    rc = pthread_create(data->threads[index], NULL, test_invalid_channel, data->co);
   }
-  for(i = 0; i < CHANNEL_COUNT; ++i) {
-    pthread_join(threads[i], NULL);
+  
+  return rc;
+}
+
+void test_channel_handling(conn_t *co)
+{
+  chnl_t *channel = NULL;
+  int rc = 0, i = 0;
+  
+  for(i = 0; i < ITERATION_COUNT; ++i) {
+    rc = channel_open(co, &channel, 12);
+    log_assert("channel open function", rc, 0);
+    rc = channel_close(channel);
+    log_assert("channel close function", rc, 0);
   }
-  printf("---------------===========   Testing end   ===========------------------\n");
-  return 0;  
 }
-           
-/*static*/ int test_error_codes(conn_t *co)
+
+void test_message_handling(conn_t* co)
 {
-  printf("---------------===========   Error codes   ===========------------------\n");
   chnl_t *channel = NULL;
-  // there is no such channel on the server
-  assert(channel_open(co, &channel, 777) == EINVAL);
+  int rc = 0, i = 0, a = 0, b = 0;
+  sexp_t *sx = NULL;
+  char *buf = NULL;
+  sxmsg_t *msg = NULL;
   
-  printf("---------------=========== Error codes end ===========------------------\n");
-  return 0;
+  buf = malloc(4096);
+  rc = channel_open(co, &channel, 12);
+  log_assert("channel open function", rc, 0);
+  for(i = 0; i < ITERATION_COUNT; ++i) {
+    a = rand() % 100;
+    b = rand() % 100;
+    sprintf(buf, "(ar-add (%d %d))", a, b);
+    sx = parse_sexp(buf, strlen(buf));
+    rc = msg_send(channel, sx, &msg);
+    log_assert("message send function", rc, a + b);
+    // destroy_sexp(sx);
+  }
+  rc = channel_close(channel);
+  free(buf);
+  log_assert("channel close function", rc, 0);
 }
-           
+
 int main(int argc, char **argv)
 {
+  // set detailed signal handler
+  struct sigaction sigact;
+  sigact.sa_flags = SA_SIGINFO;
+  sigact.sa_sigaction = signal_error;
+  sigemptyset(&sigact.sa_mask);
+  sigaction(SIGFPE, &sigact, 0);
+  sigaction(SIGILL, &sigact, 0);
+  sigaction(SIGSEGV, &sigact, 0);
+  sigaction(SIGBUS, &sigact, 0);
+  
   char *rootca = NULL, *cert = NULL;
   int port = DEFAULT_PORT;
   char *addr = NULL, *login = NULL, *password = NULL;
   int opt;
+#ifndef SIMPLE_TESTING
+  int rc, i;
+#endif
   while((opt = getopt(argc, argv, "p:r:a:u:l:w:")) != -1) {
     switch(opt) {
     case 'p':
@@ -184,18 +363,44 @@ int main(int argc, char **argv)
     fprintf(stderr, "Subsystem init failed (set SSL x.509 pems): %d\n", opt);
     return opt;
   }
-
+  
   /* Tests */
   /* try to open connection */
   conn_t *co = malloc(sizeof(conn_t));
   perm_ctx_t *ctx = (perm_ctx_t *)malloc(sizeof(perm_ctx_t));
   ctx->login = login;
   ctx->passwd = password;
+
+  log_init("test.log");
+          
+  log_begin("Connection initiate");
+  log_assert("Connection initiate", connection_initiate(co, addr, port, cert, ctx), 0);
+  log_end("Connection initiate");
+
+#ifndef SIMPLE_TESTING
+  test_data_t data;
+  data.co = co;
+  rc = allocate_threads(CHANNEL_COUNT, &data);
+  log_assert("Thread list allocation", rc, 0);
+  
+  for(i = 0; i < CHANNEL_COUNT; ++i) {
+    log_assert("Channel testing", test_channels(&data, i), 0);
+  }
+  
+  rc = deallocate_threads(&data);
+  log_assert("Thread list deallocation", rc, 0);
+#endif
+#ifdef SIMPLE_TESTING
+  //test_channel_handling(co);
+  test_message_handling(co);
+#endif
+  printf("HERE!!!!\n");
+  log_begin("Connection close");
+  log_assert("Connection close", connection_close(co), 0);
+  log_end("Connection close");
+
+  log_close();
   
-  assert(connection_initiate(co, addr, port, cert, ctx) == 0);
-  assert(start_testing(co) == 0);
-  assert(test_error_codes(co) == 0);
-  assert(connection_close(co) == 0);
   
   free(rootca);
   free(cert);
diff --git a/examples/sntld.c b/examples/sntld.c
index 5477d9e..3603a53 100644
--- a/examples/sntld.c
+++ b/examples/sntld.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#define __USE_GNU
 #include <stdlib.h>
 #include <stdarg.h>
 #include <sys/types.h>
@@ -9,11 +10,50 @@
 #include <stdint.h>
 #include <getopt.h>
 #include <errno.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <execinfo.h>
+#include <sys/resource.h>
 
 #include <tdata/usrtc.h>
 #include <sexpr/sexp.h>
 #include <sntl/connection.h>
 
+void signal_error(int sig, siginfo_t *si, void *ptr)
+{
+    void* error_addr;
+    void* trace[16];
+    int    x;
+    int    trace_size;
+    char** messages;
+
+    fprintf(stderr, "Something is wrong: backtrace: \n");
+    uintptr_t fptr = (uintptr_t)(si->si_addr);
+    fprintf(stderr, "Signal: %d, function pointer: 0x%.12lX \n", sig, fptr);
+    #if __WORDSIZE == 64
+        error_addr = (void*)((ucontext_t*)ptr)->uc_mcontext.gregs[REG_RIP];
+    #else
+        error_addr = (void*)((ucontext_t*)ptr)->uc_mcontext.gregs[REG_EIP];
+    #endif
+
+    trace_size = backtrace(trace, 16);
+    trace[1] = error_addr;
+
+    messages = backtrace_symbols(trace, trace_size);
+    if (messages)
+    {
+        for (x = 1; x < trace_size; x++)
+        {
+          fprintf(stderr, "%s\n", messages[x]);
+        }
+        free(messages);
+    }
+    
+    fprintf(stderr, "end of backtrace\n");
+
+    exit(1);
+}
+
 /* helper functions */
 int __openlistener(int port)
 {
@@ -75,6 +115,8 @@ usrtc_t *__rettlist(conn_t *c)
 /* RPC functions implementation */
 static int __ar_add(void *m, sexp_t *sx)
 {
+//  int timout = rand() % 1000000;
+//  usleep(timout);
   sexp_t *lsx = NULL, *sx_iter;
   sxmsg_t *msg = (sxmsg_t *)m;
   int idx, rc = 0;
@@ -126,6 +168,16 @@ static int __ar_multiply(void *data, sexp_t *sx)
 
 int main(int argc, char **argv)
 {
+  // set detailed signal handler
+  struct sigaction sigact;
+  sigact.sa_flags = SA_SIGINFO;
+  sigact.sa_sigaction = signal_error;
+  sigemptyset(&sigact.sa_mask);
+  sigaction(SIGFPE, &sigact, 0);
+  sigaction(SIGILL, &sigact, 0);
+  sigaction(SIGSEGV, &sigact, 0);
+  sigaction(SIGBUS, &sigact, 0);
+  
   char *rootca = NULL, *cert = NULL;
   int port = DEFAULT_PORT;
   int opt;