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

Signed-off-by: TejaswineeL <[email protected]>

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

@@ -14,8 +14,6 @@
                      * ../../../include/arch/x86_64/linux/ucontext.h:136:5: error: unknown type name ‘__sigset_t’
                      *      __sigset_t uc_sigmask;
                      */
-
-#include <dirent.h>
 #include <linux/signal.h>
 #include <stdbool.h>
 
@@ -190,39 +188,31 @@ static void handle_dummy_signal(int signum, siginfo_t* info, struct ucontext* uc
     /* we need this handler to interrupt blocking syscalls in RPC threads */
 }
 
-static int send_sigusr1_signal_to_children(void) {
-    int signal_counter= 0;
+static size_t send_sigusr1_signal_to_children(pid_t main_tid) {
+    size_t no_of_signal_sent = 0;
 
-    for (size_t i = 1; i < MAX_DBG_THREADS; i++) {
+    for (size_t i = 0; i < MAX_DBG_THREADS; i++) {
         int child_tid = ((struct enclave_dbginfo*)DBGINFO_ADDR)->thread_tids[i];
-        if(child_tid > 0) {
+        if (child_tid == main_tid)
+            continue;
+
+        if (child_tid) {
             DO_SYSCALL(tkill, child_tid, SIGUSR1);
-            signal_counter++;
+            no_of_signal_sent++;
         }
     }
-
-    return signal_counter;
+    return no_of_signal_sent;
 }
 
-static void dump_and_reset_stats(void)
-{
-    static atomic_int no_of_children_visited = 0;
-    static const uint64_t LOOP_ATTEMPTS_MAX = 10000;   /* rather arbitrary */
-
-    if(DO_SYSCALL(gettid) == g_host_pid) {
-        int no_of_children = send_sigusr1_signal_to_children();
-        uint64_t loop_attempts = 0;
-
-        /* Wait here until all the children are done processing the signal. */
-        while((no_of_children) > (__atomic_load_n(&no_of_children_visited, __ATOMIC_ACQUIRE))) {
-            if (loop_attempts == LOOP_ATTEMPTS_MAX) {
-                DO_SYSCALL(sched_yield);
-            } else {
-                loop_attempts++;
-                CPU_RELAX();
-            }
-        }
+static void dump_and_reset_stats(void) {
+    static size_t no_of_children_visited = 0;
 
+    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)) {
+            DO_SYSCALL(sched_yield);
+        }
         update_and_print_stats(/*process_wide=*/true);
         __atomic_store_n(&no_of_children_visited, 0, __ATOMIC_RELEASE);
     } else {
@@ -231,18 +221,15 @@ static void dump_and_reset_stats(void)
         __atomic_fetch_add(&no_of_children_visited, 1, __ATOMIC_ACQ_REL);
     }
 
-    PAL_HOST_TCB* tcb = pal_get_host_tcb();
-    int ret = pal_host_tcb_reset_stats(tcb);
-    if(ret < 0)
-        return;
+    pal_host_tcb_reset_stats();
 }
 
 static void handle_sigusr1(int signum, siginfo_t* info, struct ucontext* uc) {
     __UNUSED(signum);
     __UNUSED(info);
     __UNUSED(uc);
 
-    if(g_sgx_enable_stats)
+    if (g_sgx_enable_stats)
         dump_and_reset_stats();
 
     return;

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

@@ -65,8 +65,9 @@ void update_and_print_stats(bool process_wide) {
                    "  # of AEXs:           %lu\n"
                    "  # of sync signals:   %lu\n"
                    "  # of async signals:  %lu",
-                   pid, g_eenter_cnt, g_eexit_cnt, g_aex_cnt,
-                   g_sync_signal_cnt, g_async_signal_cnt);
+                   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);
         __atomic_store_n(&g_eexit_cnt, 0, __ATOMIC_RELEASE);
@@ -93,21 +94,13 @@ void pal_host_tcb_init(PAL_HOST_TCB* tcb, void* stack, void* alt_stack) {
     tcb->last_async_event = PAL_EVENT_NO_EVENT;
 }
 
-int pal_host_tcb_reset_stats(PAL_HOST_TCB* tcb) {
+void pal_host_tcb_reset_stats(void) {
+    PAL_HOST_TCB* tcb = pal_get_host_tcb();
     tcb->eenter_cnt       = 0;
     tcb->eexit_cnt        = 0;
     tcb->aex_cnt          = 0;
     tcb->sync_signal_cnt  = 0;
     tcb->async_signal_cnt = 0;
-
-    int ret;
-
-    ret = DO_SYSCALL(arch_prctl, ARCH_SET_GS, tcb);
-    if (ret < 0) {
-        ret = -EPERM;
-        log_always("error at pal_thread_reset_stats %d", ret);
-    }
-    return ret;
 }
 
 int create_tcs_mapper(void* tcs_base, unsigned int thread_num) {

pal/src/host/linux-sgx/pal_tcb.h

@@ -108,7 +108,7 @@ typedef struct pal_host_tcb {
 } PAL_HOST_TCB;
 
 extern void pal_host_tcb_init(PAL_HOST_TCB* tcb, void* stack, void* alt_stack);
-extern int pal_host_tcb_reset_stats(PAL_HOST_TCB* tcb);
+extern void pal_host_tcb_reset_stats(void);
 
 static inline PAL_HOST_TCB* pal_get_host_tcb(void) {
     PAL_HOST_TCB* tcb;