fixup! fixup! Dump and Reset stats data on demand using SIGUSR1 signal

Signed-off-by: TejaswineeL <tejaswinee.ramdas.langhe@intel.com>

Documentation/performance.rst

@@ -103,6 +103,15 @@ How to read this output:
    counters should be compared against "golden runs" to deduce any interesting
    trends.
 
+It is also possible to reset the performance statistics interactively, using
+``SIGUSR1`` signal. This helps to collect performance statistics only for a
+particular period e.g., skipping the Gramine startup and application
+initialization time and concentrating only on the actual application processing.
+Send ``SIGUSR1`` using command ``kill -SIGUSR1 <gramine-pid>``  (note the
+minus sign before <gramine-pid>). Sending multiple ``SIGUSR1`` will result
+in a sequential dump and reset of the statistics, each dump and reset of
+statistics will be done after the previous ``SIGUSR1``.
+
 Effects of system calls / ocalls
 --------------------------------
 

pal/src/host/linux-sgx/host_exception.c

@@ -189,7 +189,7 @@ static void handle_dummy_signal(int signum, siginfo_t* info, struct ucontext* uc
 }
 
 static size_t send_sigusr1_signal_to_children(pid_t main_tid) {
-    size_t no_of_signal_sent = 0;
+    size_t no_of_signals_sent = 0;
 
     for (size_t i = 0; i < MAX_DBG_THREADS; i++) {
         int child_tid = ((struct enclave_dbginfo*)DBGINFO_ADDR)->thread_tids[i];
@@ -198,10 +198,10 @@ static size_t send_sigusr1_signal_to_children(pid_t main_tid) {
 
         if (child_tid) {
             DO_SYSCALL(tkill, child_tid, SIGUSR1);
-            no_of_signal_sent++;
+            no_of_signals_sent++;
         }
     }
-    return no_of_signal_sent;
+    return no_of_signals_sent;
 }
 
 static void dump_and_reset_stats(void) {
@@ -210,13 +210,14 @@ static void dump_and_reset_stats(void) {
     if (DO_SYSCALL(gettid) == g_host_pid) {
         size_t no_of_children = send_sigusr1_signal_to_children(g_host_pid);
 
-        while ((__atomic_load_n(&no_of_children_visited, __ATOMIC_ACQUIRE)) < (no_of_children)) {
+        while ((__atomic_load_n(&no_of_children_visited, __ATOMIC_ACQUIRE)) < no_of_children) {
             DO_SYSCALL(sched_yield);
         }
+        log_always("----- DUMPING and RESETTING SGX STATS -----");
         update_and_print_stats(/*process_wide=*/true);
         __atomic_store_n(&no_of_children_visited, 0, __ATOMIC_RELEASE);
     } else {
-        log_always("----- DUMPTING and RESETTING SGX STATS -----");
+        log_always("----- DUMPING and RESETTING SGX STATS -----");
         update_and_print_stats(/*process_wide=*/false);
         __atomic_fetch_add(&no_of_children_visited, 1, __ATOMIC_ACQ_REL);
     }
@@ -231,8 +232,6 @@ static void handle_sigusr1(int signum, siginfo_t* info, struct ucontext* uc) {
 
     if (g_sgx_enable_stats)
         dump_and_reset_stats();
-
-    return;
 }
 
 int sgx_signal_setup(void) {

pal/src/host/linux-sgx/host_thread.c

@@ -65,8 +65,10 @@ void update_and_print_stats(bool process_wide) {
                    "  # of AEXs:           %lu\n"
                    "  # of sync signals:   %lu\n"
                    "  # of async signals:  %lu",
-                   pid, __atomic_load_n(&g_eenter_cnt, __ATOMIC_ACQUIRE), __atomic_load_n(&g_eexit_cnt, __ATOMIC_ACQUIRE),
-                   __atomic_load_n(&g_aex_cnt, __ATOMIC_ACQUIRE), __atomic_load_n(&g_sync_signal_cnt, __ATOMIC_ACQUIRE),
+                   pid, __atomic_load_n(&g_eenter_cnt, __ATOMIC_ACQUIRE),
+                   __atomic_load_n(&g_eexit_cnt, __ATOMIC_ACQUIRE),
+                   __atomic_load_n(&g_aex_cnt, __ATOMIC_ACQUIRE),
+                   __atomic_load_n(&g_sync_signal_cnt, __ATOMIC_ACQUIRE),
                    __atomic_load_n(&g_async_signal_cnt, __ATOMIC_ACQUIRE));
 
         __atomic_store_n(&g_eenter_cnt, 0, __ATOMIC_RELEASE);