Changeset 4ecc35a for libcfa

Timestamp:

Mar 21, 2022, 1:28:59 PM (2 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

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

Children:

dbe2533

Parents:

98d1b90

Message:

Added spin lock to io drain.
last step before completion fairness

Location:

libcfa/src/concurrency

Files:

• io.cfa (modified) (4 diffs)
• io/setup.cfa (modified) (1 diff)
• io/types.hfa (modified) (1 diff)
• kernel.cfa (modified) (2 diffs)

libcfa/src/concurrency/io.cfa

@@ -93 +93 @@
         extern void __kernel_unpark( thread$ * thrd, unpark_hint );
 
-        bool __cfa_io_drain( processor * proc ) {
+        bool __cfa_io_drain( $io_context * ctx ) {
                 /* paranoid */ verify( ! __preemption_enabled() );
                 /* paranoid */ verify( ready_schedule_islocked() );
-                /* paranoid */ verify( proc );
-                /* paranoid */ verify( proc->io.ctx );
+                /* paranoid */ verify( ctx );
 
                 // Drain the queue
-                $io_context * ctx = proc->io.ctx;
                 unsigned head = *ctx->cq.head;
                 unsigned tail = *ctx->cq.tail;
@@ -110 +108 @@
                 if(count == 0) return false;
 
+                if(!__atomic_try_acquire(&ctx->cq.lock)) {
+                        return false;
+                }
+
                 for(i; count) {
                         unsigned idx = (head + i) & mask;
@@ -130 +132 @@
                 /* paranoid */ verify( ready_schedule_islocked() );
                 /* paranoid */ verify( ! __preemption_enabled() );
+
+                __atomic_unlock(&ctx->cq.lock);
 
                 return true;
@@ -179 +183 @@
 
                 ready_schedule_lock();
-                bool ret = __cfa_io_drain( proc );
+                bool ret = __cfa_io_drain( &ctx );
                 ready_schedule_unlock();
                 return ret;

libcfa/src/concurrency/io/setup.cfa

@@ -214 +214 @@
 
                 // completion queue
+                cq.lock      = 0;
                 cq.head      = (volatile __u32 *)(((intptr_t)cq.ring_ptr) + params.cq_off.head);
                 cq.tail      = (volatile __u32 *)(((intptr_t)cq.ring_ptr) + params.cq_off.tail);

libcfa/src/concurrency/io/types.hfa

@@ -78 +78 @@
 
         struct __cmp_ring_t {
+                volatile bool lock;
+
                 // Head and tail of the ring
                 volatile __u32 * head;

libcfa/src/concurrency/kernel.cfa

@@ -136 +136 @@
 static void mark_awake(__cluster_proc_list & idles, processor & proc);
 
-extern bool __cfa_io_drain( processor * );
+extern bool __cfa_io_drain( $io_context * );
 extern bool __cfa_io_flush( processor *, int min_comp );
 static inline bool __maybe_io_drain( processor * );
@@ -839 +839 @@
                 if(head == tail) return false;
                 ready_schedule_lock();
-                ret = __cfa_io_drain( proc );
+                ret = __cfa_io_drain( ctx );
                 ready_schedule_unlock();
         #endif