Changes in libcfa/src/concurrency/preemption.cfa [92bfda0:a3821fa]

File:

• libcfa/src/concurrency/preemption.cfa (modified) (12 diffs)

libcfa/src/concurrency/preemption.cfa

@@ -15 +15 @@
 
 #define __cforall_thread__
+// #define __CFA_DEBUG_PRINT_PREEMPTION__
 
 #include "preemption.hfa"
@@ -28 +29 @@
 #include "kernel_private.hfa"
 
+
 #if !defined(__CFA_DEFAULT_PREEMPTION__)
 #define __CFA_DEFAULT_PREEMPTION__ 10`ms
 #endif
 
-Duration default_preemption() __attribute__((weak)) {
-        return __CFA_DEFAULT_PREEMPTION__;
+__attribute__((weak)) Duration default_preemption() {
+        const char * preempt_rate_s = getenv("CFA_DEFAULT_PREEMPTION");
+        if(!preempt_rate_s) {
+                __cfadbg_print_safe(preemption, "No CFA_DEFAULT_PREEMPTION in ENV\n");
+                return __CFA_DEFAULT_PREEMPTION__;
+        }
+
+        char * endptr = 0p;
+        long int preempt_rate_l = strtol(preempt_rate_s, &endptr, 10);
+        if(preempt_rate_l < 0 || preempt_rate_l > 65535) {
+                __cfadbg_print_safe(preemption, "CFA_DEFAULT_PREEMPTION out of range : %ld\n", preempt_rate_l);
+                return __CFA_DEFAULT_PREEMPTION__;
+        }
+        if('\0' != *endptr) {
+                __cfadbg_print_safe(preemption, "CFA_DEFAULT_PREEMPTION not a decimal number : %s\n", preempt_rate_s);
+                return __CFA_DEFAULT_PREEMPTION__;
+        }
+
+        return preempt_rate_l`ms;
 }
 
@@ -98 +117 @@
         //Loop throught every thing expired
         while( node = get_expired( alarms, currtime ) ) {
-                // __cfaabi_dbg_print_buffer_decl( " KERNEL: preemption tick.\n" );
+                __cfadbg_print_buffer_decl( preemption, " KERNEL: preemption tick %lu\n", currtime.tn);
                 Duration period = node->period;
                 if( period == 0) {
@@ -104 +123 @@
                 }
 
+                __cfadbg_print_buffer_local( preemption, " KERNEL: alarm ticking node %p.\n", node );
+
+
                 // Check if this is a kernel
                 if( node->type == Kernel ) {
@@ -109 +131 @@
                 }
                 else if( node->type == User ) {
+                        __cfadbg_print_buffer_local( preemption, " KERNEL: alarm unparking %p.\n", node->thrd );
                         timeout( node->thrd );
                 }
@@ -117 +140 @@
                 // Check if this is a periodic alarm
                 if( period > 0 ) {
-                        // __cfaabi_dbg_print_buffer_local( " KERNEL: alarm period is %lu.\n", period.tv );
+                        __cfadbg_print_buffer_local( preemption, " KERNEL: alarm period is %lu.\n", period`ns );
                         node->alarm = currtime + period;    // Alarm is periodic, add currtime to it (used cached current time)
                         insert( alarms, node );             // Reinsert the node for the next time it triggers
@@ -125 +148 @@
         // If there are still alarms pending, reset the timer
         if( & (*alarms)`first ) {
-                __cfadbg_print_buffer_decl(preemption, " KERNEL: @%ju(%ju) resetting alarm to %ju.\n", currtime.tv, __kernel_get_time().tv, (alarms->head->alarm - currtime).tv);
                 Duration delta = (*alarms)`first.alarm - currtime;
                 Duration capped = max(delta, 50`us);
-                // itimerval tim  = { caped };
-                // __cfaabi_dbg_print_buffer_local( "    Values are %lu, %lu, %lu %lu.\n", delta.tv, caped.tv, tim.it_value.tv_sec, tim.it_value.tv_usec);
-
                 __kernel_set_timer( capped );
         }
@@ -296 +315 @@
         // Enable interrupts by decrementing the counter
         // If counter reaches 0, execute any pending __cfactx_switch
-        void enable_interrupts( __cfaabi_dbg_ctx_param ) {
+        void enable_interrupts( bool poll ) {
                 // Cache the processor now since interrupts can start happening after the atomic store
                 processor   * proc = __cfaabi_tls.this_processor;
-                /* paranoid */ verify( proc );
+                /* paranoid */ verify( !poll || proc );
 
                 with( __cfaabi_tls.preemption_state ){
@@ -321 +340 @@
                                 // Signal the compiler that a fence is needed but only for signal handlers
                                 __atomic_signal_fence(__ATOMIC_RELEASE);
-                                if( proc->pending_preemption ) {
+                                if( poll && proc->pending_preemption ) {
                                         proc->pending_preemption = false;
                                         force_yield( __POLL_PREEMPTION );
                                 }
                         }
-                }
-
-                // For debugging purposes : keep track of the last person to enable the interrupts
-                __cfaabi_dbg_debug_do( proc->last_enable = caller; )
-        }
-
-        // Disable interrupts by incrementint the counter
-        // Don't execute any pending __cfactx_switch even if counter reaches 0
-        void enable_interrupts_noPoll() {
-                unsigned short prev = __cfaabi_tls.preemption_state.disable_count;
-                __cfaabi_tls.preemption_state.disable_count -= 1;
-                // If this triggers someone is enabled already enabled interrupts
-                /* paranoid */ verifyf( prev != 0u, "Incremented from %u\n", prev );
-                if( prev == 1 ) {
-                        #if GCC_VERSION > 50000
-                                static_assert(__atomic_always_lock_free(sizeof(__cfaabi_tls.preemption_state.enabled), &__cfaabi_tls.preemption_state.enabled), "Must be lock-free");
-                        #endif
-                        // Set enabled flag to true
-                        // should be atomic to avoid preemption in the middle of the operation.
-                        // use memory order RELAXED since there is no inter-thread on this variable requirements
-                        __atomic_store_n(&__cfaabi_tls.preemption_state.enabled, true, __ATOMIC_RELAXED);
-
-                        // Signal the compiler that a fence is needed but only for signal handlers
-                        __atomic_signal_fence(__ATOMIC_RELEASE);
                 }
         }
@@ -585 +580 @@
 
         // Setup proper signal handlers
-        __cfaabi_sigaction( SIGUSR1, sigHandler_ctxSwitch, SA_SIGINFO | SA_RESTART ); // __cfactx_switch handler
-        __cfaabi_sigaction( SIGALRM, sigHandler_alarm    , SA_SIGINFO | SA_RESTART ); // debug handler
+        __cfaabi_sigaction( SIGUSR1, sigHandler_ctxSwitch, SA_SIGINFO ); // __cfactx_switch handler
+        __cfaabi_sigaction( SIGALRM, sigHandler_alarm    , SA_SIGINFO ); // debug handler
 
         signal_block( SIGALRM );
@@ -689 +684 @@
 }
 
-#if !defined(__CFA_NO_STATISTICS__)
-        int __print_alarm_stats = 0;
-#endif
-
 // Main of the alarm thread
 // Waits on SIGALRM and send SIGUSR1 to whom ever needs it
 static void * alarm_loop( __attribute__((unused)) void * args ) {
         __processor_id_t id;
-        id.full_proc = false;
-        id.id = doregister(&id);
+        register_proc_id(&id);
         __cfaabi_tls.this_proc_id = &id;
 
-        #if !defined(__CFA_NO_STATISTICS__)
-                struct __stats_t local_stats;
-                __cfaabi_tls.this_stats = &local_stats;
-                __init_stats( &local_stats );
-        #endif
 
         // Block sigalrms to control when they arrive
@@ -764 +749 @@
 EXIT:
         __cfaabi_dbg_print_safe( "Kernel : Preemption thread stopping\n" );
-        unregister(&id);
-
-        #if !defined(__CFA_NO_STATISTICS__)
-                if( 0 != __print_alarm_stats ) {
-                        __print_stats( &local_stats, __print_alarm_stats, "Alarm", "Thread", 0p );
-                }
-        #endif
+        register_proc_id(&id);
+
         return 0p;
 }