Changeset 8fcbb4c for src/libcfa

Timestamp:

Feb 9, 2017, 4:51:40 PM (8 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, resolv-new, with_gc

Children:

8d4f7fe

Parents:

84e2523

Message:

removed pthread_spinlock_t and fixed race condition in yield

Location:

src/libcfa/concurrency

Files:

• kernel (modified) (3 diffs)
• kernel.c (modified) (18 diffs)
• threads.c (modified) (3 diffs)

src/libcfa/concurrency/kernel

@@ -30 +30 @@
 struct cluster {
         simple_thread_list ready_queue;
-        pthread_spinlock_t lock;
+        // pthread_spinlock_t lock;
 };
 
@@ -38 +38 @@
 //-----------------------------------------------------------------------------
 // Processor
+enum ProcessorAction { 
+        Reschedule,
+        NoAction
+};
+
 struct processor {
-        struct processorCtx_t * ctx;
+        struct processorCtx_t * runner;
         cluster * cltr;
         coroutine * current_coroutine;
@@ -46 +51 @@
         simple_lock lock;
         volatile bool terminated;
+        ProcessorAction thread_action;
 };
 

src/libcfa/concurrency/kernel.c

@@ -25 +25 @@
 #include <stddef.h>
 extern "C" {
+#include <fenv.h>
 #include <sys/resource.h>
 }
@@ -35 +36 @@
 #define __CFA_INVOKE_PRIVATE__
 #include "invoke.h"
+
+static volatile int lock;
+
+void spin_lock( volatile int *lock ) {
+        for ( unsigned int i = 1;; i += 1 ) {
+          if ( *lock == 0 && __sync_lock_test_and_set_4( lock, 1 ) == 0 ) break;
+        }
+}
+
+void spin_unlock( volatile int *lock ) {
+        __sync_lock_release_4( lock );
+}
 
 //-----------------------------------------------------------------------------
@@ -127 +140 @@
         (&this->c){};
         this->proc = proc;
-        proc->ctx = this;
+        proc->runner = this;
 }
 
@@ -133 +146 @@
         (&this->c){ info };
         this->proc = proc;
-        proc->ctx = this;
+        proc->runner = this;
 }
 
@@ -152 +165 @@
 }
 
-void ?{}(processor * this, cluster * cltr, processorCtx_t * ctx) {
+void ?{}(processor * this, cluster * cltr, processorCtx_t * runner) {
         this->cltr = cltr;
         this->current_coroutine = NULL;
@@ -159 +172 @@
         this->terminated = false;
 
-        this->ctx = ctx;
-        LIB_DEBUG_PRINTF("Kernel : constructing processor context %p\n", ctx);
-        ctx{ this };
+        this->runner = runner;
+        LIB_DEBUG_PRINTF("Kernel : constructing processor context %p\n", runner);
+        runner{ this };
 }
 
@@ -174 +187 @@
 void ?{}(cluster * this) {
         ( &this->ready_queue ){};
-        pthread_spin_init( &this->lock, PTHREAD_PROCESS_PRIVATE );
+        lock = 0;
 }
 
 void ^?{}(cluster * this) {
-        pthread_spin_destroy( &this->lock );
+        
 }
 
 //-----------------------------------------------------------------------------
 // Processor running routines
-void main(processorCtx_t * ctx);
+void main(processorCtx_t *);
 thread * nextThread(cluster * this);
 void scheduleInternal(processor * this, thread * dst);
 void spin(processor * this, unsigned int * spin_count);
-
-void main(processorCtx_t * ctx) {
-        processor * this = ctx->proc;
+void thread_schedule( thread * thrd );
+
+//Main of the processor contexts
+void main(processorCtx_t * runner) {
+        processor * this = runner->proc;
         LIB_DEBUG_PRINTF("Kernel : core %p starting\n", this);
+
+        fenv_t envp;
+        fegetenv( &envp );
+        LIB_DEBUG_PRINTF("Kernel : mxcsr %x\n", envp.__mxcsr);
 
         thread * readyThread = NULL;
@@ -216 +235 @@
 // from the processor coroutine to the target thread 
 void scheduleInternal(processor * this, thread * dst) {
+        this->thread_action = NoAction;
+
         // coroutine * proc_ctx = get_coroutine(this->ctx);
         // coroutine * thrd_ctx = get_coroutine(dst);
@@ -226 +247 @@
         // // when ThreadCtxSwitch returns we are back in the processor coroutine
 
-        coroutine * proc_ctx = get_coroutine(this->ctx);
+        coroutine * proc_ctx = get_coroutine(this->runner);
         coroutine * thrd_ctx = get_coroutine(dst);
       thrd_ctx->last = proc_ctx;
@@ -232 +253 @@
       // context switch to specified coroutine
       // Which is now the current_coroutine
-      LIB_DEBUG_PRINTF("Kernel : switching to ctx %p (from %p, current %p)\n", thrd_ctx, proc_ctx, this->current_coroutine);
+      // LIB_DEBUG_PRINTF("Kernel : switching to ctx %p (from %p, current %p)\n", thrd_ctx, proc_ctx, this->current_coroutine);
       this->current_thread = dst;
       this->current_coroutine = thrd_ctx;
       CtxSwitch( proc_ctx->stack.context, thrd_ctx->stack.context );
       this->current_coroutine = proc_ctx;
-      LIB_DEBUG_PRINTF("Kernel : returned from ctx %p (to %p, current %p)\n", thrd_ctx, proc_ctx, this->current_coroutine);
+      // LIB_DEBUG_PRINTF("Kernel : returned from ctx %p (to %p, current %p)\n", thrd_ctx, proc_ctx, this->current_coroutine);
  
       // when CtxSwitch returns we are back in the processor coroutine
+        if(this->thread_action == Reschedule) {
+                thread_schedule( dst );
+        }
 }
 
@@ -262 +286 @@
         processorCtx_t proc_cor_storage = { proc, &info };
 
+        LIB_DEBUG_PRINTF("Coroutine : created stack %p\n", proc_cor_storage.c.stack.base);
+
         //Set global state
-        proc->current_coroutine = &proc->ctx->c;
+        proc->current_coroutine = &proc->runner->c;
         proc->current_thread = NULL;
 
         //We now have a proper context from which to schedule threads
-        LIB_DEBUG_PRINTF("Kernel : core %p created (%p)\n", proc, proc->ctx);
+        LIB_DEBUG_PRINTF("Kernel : core %p created (%p, %p)\n", proc, proc->runner, &ctx);
 
         // SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't 
@@ -279 +305 @@
 
         // Main routine of the core returned, the core is now fully terminated
-        LIB_DEBUG_PRINTF("Kernel : core %p main ended (%p)\n", proc, proc->ctx);        
+        LIB_DEBUG_PRINTF("Kernel : core %p main ended (%p)\n", proc, proc->runner);     
 
         return NULL;
@@ -287 +313 @@
         LIB_DEBUG_PRINTF("Kernel : Starting core %p\n", this);
         
-        pthread_attr_t attributes;
-        pthread_attr_init( &attributes );
-
-        pthread_create( &this->kernel_thread, &attributes, CtxInvokeProcessor, (void*)this );
-
-        pthread_attr_destroy( &attributes );
+        // pthread_attr_t attributes;
+        // pthread_attr_init( &attributes );
+
+        pthread_create( &this->kernel_thread, NULL, CtxInvokeProcessor, (void*)this );
+
+        // pthread_attr_destroy( &attributes );
 
         LIB_DEBUG_PRINTF("Kernel : core %p started\n", this);   
@@ -302 +328 @@
         assertf( thrd->next == NULL, "Expected null got %p", thrd->next );
         
-        pthread_spinlock_guard guard = { &systemProcessor->cltr->lock };
+        spin_lock( &lock );
         append( &systemProcessor->cltr->ready_queue, thrd );
+        spin_unlock( &lock );
 }
 
 thread * nextThread(cluster * this) {
-        pthread_spinlock_guard guard = { &this->lock };
-        return pop_head( &this->ready_queue );
+        spin_lock( &lock );
+        thread * head = pop_head( &this->ready_queue );
+        spin_unlock( &lock );
+        return head;
 }
 
@@ -314 +343 @@
 // Kernel boot procedures
 void kernel_startup(void) {
-
+        LIB_DEBUG_PRINTF("Kernel : Starting\n");        
+
+        // Start by initializing the main thread
         // SKULLDUGGERY: the mainThread steals the process main thread 
         // which will then be scheduled by the systemProcessor normally
-        LIB_DEBUG_PRINTF("Kernel : Starting\n");        
-
+        mainThread = (thread *)&mainThread_storage;
         current_stack_info_t info;
-
-        // LIB_DEBUG_PRINTF("Kernel : core    base : %p \n", info.base );
-        // LIB_DEBUG_PRINTF("Kernel : core storage : %p \n", info.storage );
-        // LIB_DEBUG_PRINTF("Kernel : core    size : %x \n", info.size );
-        // LIB_DEBUG_PRINTF("Kernel : core   limit : %p \n", info.limit );
-        // LIB_DEBUG_PRINTF("Kernel : core context : %p \n", info.context );
-        // LIB_DEBUG_PRINTF("Kernel : core     top : %p \n", info.top );
-
-        // Start by initializing the main thread
-        mainThread = (thread *)&mainThread_storage;
         mainThread{ &info };
 
@@ -353 +373 @@
         // context. Hence, the main thread does not begin through CtxInvokeThread, like all other threads. The trick here is that
         // mainThread is on the ready queue when this call is made. 
-        resume(systemProcessor->ctx);
+        resume(systemProcessor->runner);
 
 
 
         // THE SYSTEM IS NOW COMPLETELY RUNNING
-
-
-
         LIB_DEBUG_PRINTF("Kernel : Started\n--------------------------------------------------\n\n");
 }
@@ -377 +394 @@
         // Destroy the system processor and its context in reverse order of construction
         // These were manually constructed so we need manually destroy them
-        ^(systemProcessor->ctx){};
+        ^(systemProcessor->runner){};
         ^(systemProcessor){};
 
@@ -399 +416 @@
 void lock( simple_lock * this ) {
         {
-                pthread_spinlock_guard guard = { &systemCluster->lock };        //HUGE TEMP HACK which only works if we have a single cluster and is stupid
+                spin_lock( &lock );
                 append( &this->blocked, this_thread() );
+                spin_unlock( &lock );
         }
         suspend();

src/libcfa/concurrency/threads.c

@@ -24 +24 @@
 
 extern "C" {
+        #include <fenv.h>
         #include <stddef.h>
 }
@@ -91 +92 @@
         CtxSwitch( thrd_c->last->stack.context, thrd_c->stack.context );
 
+        fenv_t envp;
+        fegetenv( &envp );
+        LIB_DEBUG_PRINTF("Thread : mxcsr %x\n", envp.__mxcsr);
         LIB_DEBUG_PRINTF("Thread started : %p (t %p, c %p)\n", this, thrd_c, thrd_h);
 
@@ -105 +109 @@
 
 void yield( void ) {
-        thread_schedule( this_thread() );
+        get_this_processor()->thread_action = Reschedule;
         suspend();
 }