Changeset 18f7858 for libcfa/src/concurrency/kernel.cfa

Timestamp:

Mar 28, 2022, 4:00:32 PM (2 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, ast-experimental, enum, master, pthread-emulation, qualifiedEnum

Children:

37a3aa23

Parents:

2377ca2

Message:

Refactored io to allow holding the lock duirng idle sleep

File:

• libcfa/src/concurrency/kernel.cfa (modified) (10 diffs)

libcfa/src/concurrency/kernel.cfa

@@ -132 +132 @@
 static void __wake_one(cluster * cltr);
 
-static void idle_sleep(processor * proc, io_future_t & future, iovec & iov);
+static void idle_sleep(processor * proc);
 static bool mark_idle (__cluster_proc_list & idles, processor & proc);
 static void mark_awake(__cluster_proc_list & idles, processor & proc);
 
 extern bool __cfa_io_drain( processor * proc ) __attribute__((nonnull (1)));
-extern bool __cfa_io_flush( processor *, int min_comp );
-static inline bool __maybe_io_drain( processor * );
+extern bool __cfa_io_flush( processor * ) __attribute__((nonnull (1)));
+extern void __cfa_io_idle( processor * ) __attribute__((nonnull (1)));
 
 #if defined(CFA_WITH_IO_URING_IDLE)
@@ -168 +168 @@
         // mark it as already fulfilled so we know if there is a pending request or not
         this->idle_wctx.ftr->self.ptr = 1p;
-        iovec idle_iovec = { this->idle_wctx.rdbuf, sizeof(eventfd_t) };
 
         __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
@@ -193 +192 @@
                 for() {
                         // Check if there is pending io
-                        __maybe_io_drain( this );
+                        __cfa_io_drain( this );
 
                         // Try to get the next thread
@@ -199 +198 @@
 
                         if( !readyThread ) {
+                                // there is no point in holding submissions if we are idle
                                 __IO_STATS__(true, io.flush.idle++; )
-                                __cfa_io_flush( this, 0 );
+                                __cfa_io_flush( this );
+
+                                // drain again in case something showed up
+                                __cfa_io_drain( this );
 
                                 readyThread = __next_thread( this->cltr );
@@ -206 +209 @@
 
                         if( !readyThread ) for(5) {
+                                readyThread = __next_thread_slow( this->cltr );
+
+                                if( readyThread ) break;
+
+                                // It's unlikely we still I/O to submit, but the arbiter could
                                 __IO_STATS__(true, io.flush.idle++; )
-
-                                readyThread = __next_thread_slow( this->cltr );
-
-                                if( readyThread ) break;
-
-                                __cfa_io_flush( this, 0 );
+                                __cfa_io_flush( this );
+
+                                // drain again in case something showed up
+                                __cfa_io_drain( this );
                         }
 
@@ -235 +241 @@
                                 }
 
-                                idle_sleep( this, *this->idle_wctx.ftr, idle_iovec );
+                                idle_sleep( this );
 
                                 // We were woken up, remove self from idle
@@ -257 +263 @@
                         if(__atomic_load_n(&this->io.pending, __ATOMIC_RELAXED) && !__atomic_load_n(&this->io.dirty, __ATOMIC_RELAXED)) {
                                 __IO_STATS__(true, io.flush.dirty++; )
-                                __cfa_io_flush( this, 0 );
+                                __cfa_io_flush( this );
                         }
                 }
@@ -683 +689 @@
 }
 
-static void idle_sleep(processor * this, io_future_t & future, iovec & iov) {
+static void idle_sleep(processor * this) {
         /* paranoid */ verify( this->idle_wctx.evfd != 1 );
         /* paranoid */ verify( this->idle_wctx.evfd != 2 );
@@ -735 +741 @@
                 #endif
         #else
-                // Do we already have a pending read
-                if(available(future)) {
-                        // There is no pending read, we need to add one
-                        reset(future);
-
-                        __kernel_read(this, future, iov, this->idle_wctx.evfd );
-                }
-
-                __cfa_io_flush( this, 1 );
+                __cfa_io_idle( this );
         #endif
 }
@@ -831 +829 @@
 #endif
 
-static inline bool __maybe_io_drain( processor * proc ) {
-        /* paranoid */ verify( proc );
-        bool ret = false;
-        #if defined(CFA_HAVE_LINUX_IO_URING_H)
-                __cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
-
-                // Check if we should drain the queue
-                $io_context * ctx = proc->io.ctx;
-                unsigned head = *ctx->cq.head;
-                unsigned tail = *ctx->cq.tail;
-                if(head == tail) return false;
-                ready_schedule_lock();
-                ret = __cfa_io_drain( proc );
-                ready_schedule_unlock();
-        #endif
-        return ret;
-}
+
 
 //-----------------------------------------------------------------------------