Changeset 040334e

Timestamp:

Jan 27, 2022, 1:16:42 PM (23 months ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, ast-experimental, enum, forall-pointer-decay, master, pthread-emulation, qualifiedEnum

Children:

ac6fc48

Parents:

00a8e19

Message:

Removed so-called 'new proc main' which wasn't useful.

File:

• libcfa/src/concurrency/kernel.cfa (modified) (3 diffs)

libcfa/src/concurrency/kernel.cfa

@@ -187 +187 @@
                 MAIN_LOOP:
                 for() {
-                        #define OLD_MAIN 1
-                        #if OLD_MAIN
                         // Check if there is pending io
                         __maybe_io_drain( this );
@@ -248 +246 @@
                                 __cfa_io_flush( this, 0 );
                         }
-
-                        #else
-                                #warning new kernel loop
-                        SEARCH: {
-                                /* paranoid */ verify( ! __preemption_enabled() );
-
-                                // First, lock the scheduler since we are searching for a thread
-                                ready_schedule_lock();
-
-                                // Try to get the next thread
-                                readyThread = pop_fast( this->cltr );
-                                if(readyThread) { ready_schedule_unlock(); break SEARCH; }
-
-                                // If we can't find a thread, might as well flush any outstanding I/O
-                                if(this->io.pending) { __cfa_io_flush( this, 0 ); }
-
-                                // Spin a little on I/O, just in case
-                                for(5) {
-                                        __maybe_io_drain( this );
-                                        readyThread = pop_fast( this->cltr );
-                                        if(readyThread) { ready_schedule_unlock(); break SEARCH; }
-                                }
-
-                                // no luck, try stealing a few times
-                                for(5) {
-                                        if( __maybe_io_drain( this ) ) {
-                                                readyThread = pop_fast( this->cltr );
-                                        } else {
-                                                readyThread = pop_slow( this->cltr );
-                                        }
-                                        if(readyThread) { ready_schedule_unlock(); break SEARCH; }
-                                }
-
-                                // still no luck, search for a thread
-                                readyThread = pop_search( this->cltr );
-                                if(readyThread) { ready_schedule_unlock(); break SEARCH; }
-
-                                // Don't block if we are done
-                                if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) {
-                                        ready_schedule_unlock();
-                                        break MAIN_LOOP;
-                                }
-
-                                __STATS( __tls_stats()->ready.sleep.halts++; )
-
-                                // Push self to idle stack
-                                ready_schedule_unlock();
-                                if(!mark_idle(this->cltr->procs, * this)) goto SEARCH;
-                                ready_schedule_lock();
-
-                                // Confirm the ready-queue is empty
-                                __maybe_io_drain( this );
-                                readyThread = pop_search( this->cltr );
-                                ready_schedule_unlock();
-
-                                if( readyThread ) {
-                                        // A thread was found, cancel the halt
-                                        mark_awake(this->cltr->procs, * this);
-
-                                        __STATS( __tls_stats()->ready.sleep.cancels++; )
-
-                                        // continue the main loop
-                                        break SEARCH;
-                                }
-
-                                __STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl()); )
-                                __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle_fd);
-
-                                {
-                                        eventfd_t val;
-                                        ssize_t ret = read( this->idle_fd, &val, sizeof(val) );
-                                        if(ret < 0) {
-                                                switch((int)errno) {
-                                                case EAGAIN:
-                                                #if EAGAIN != EWOULDBLOCK
-                                                        case EWOULDBLOCK:
-                                                #endif
-                                                case EINTR:
-                                                        // No need to do anything special here, just assume it's a legitimate wake-up
-                                                        break;
-                                                default:
-                                                        abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
-                                                }
-                                        }
-                                }
-
-                                        __STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl()); )
-
-                                // We were woken up, remove self from idle
-                                mark_awake(this->cltr->procs, * this);
-
-                                // DON'T just proceed, start looking again
-                                continue MAIN_LOOP;
-                        }
-
-                RUN_THREAD:
-                        /* paranoid */ verify( ! __preemption_enabled() );
-                        /* paranoid */ verify( readyThread );
-
-                        // Reset io dirty bit
-                        this->io.dirty = false;
-
-                        // We found a thread run it
-                        __run_thread(this, readyThread);
-
-                        // Are we done?
-                        if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
-
-                        if(this->io.pending && !this->io.dirty) {
-                                __cfa_io_flush( this, 0 );
-                        }
-
-                        ready_schedule_lock();
-                        __maybe_io_drain( this );
-                        ready_schedule_unlock();
-                        #endif
                 }
 
@@ -951 +833 @@
                 unsigned tail = *ctx->cq.tail;
                 if(head == tail) return false;
-                #if OLD_MAIN
-                        ready_schedule_lock();
-                        ret = __cfa_io_drain( proc );
-                        ready_schedule_unlock();
-                #else
-                        ret = __cfa_io_drain( proc );
-                #endif
+                ready_schedule_lock();
+                ret = __cfa_io_drain( proc );
+                ready_schedule_unlock();
         #endif
         return ret;