Changeset 04b5cef for libcfa/src/concurrency

Timestamp:

Jun 19, 2020, 11:22:32 AM (4 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

64a7146

Parents:

37ba662

Message:

Added BIAS option to ready_queue
Added yield test for LibFibre?
Fixed some alignments and minor optimizations

Location:

libcfa/src/concurrency

Files:

• kernel.cfa (modified) (1 diff)
• ready_queue.cfa (modified) (4 diffs)

libcfa/src/concurrency/kernel.cfa

@@ -342 +342 @@
                                 /* paranoid */ verifyf( readyThread->state == Ready || readyThread->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", readyThread->state, readyThread->preempted);
                                 /* paranoid */ verifyf( readyThread->link.next == 0p, "Expected null got %p", readyThread->link.next );
+                                __builtin_prefetch( readyThread->context.SP );
 
                                 // We found a thread run it

libcfa/src/concurrency/ready_queue.cfa

@@ -24 +24 @@
 #include "math.hfa"
 
+#include <unistd.h>
+
 static const size_t cache_line_size = 64;
 
@@ -31 +33 @@
         #define __CFA_MAX_PROCESSORS__ 1024
 #endif
+
+#define BIAS 64
 
 // returns the maximum number of processors the RWLock support
@@ -568 +572 @@
         do {
                 // Pick the index of a lane
-                i = __tls_rand() % lanes.count;
+                #if defined(BIAS)
+                        unsigned r = __tls_rand();
+                        unsigned rlow  = r % BIAS;
+                        unsigned rhigh = r / BIAS;
+                        if(0 != (rlow % BIAS) && kernelTLS.this_processor) {
+                                // (BIAS - 1) out of BIAS chances
+                                // Use perferred queues
+                                i = (kernelTLS.this_processor->id * 4) + (rhigh % 4);
+                        }
+                        else {
+                                // 1 out of BIAS chances
+                                // Use all queues
+                                i = rhigh;
+                        }
+                #else
+                        i = __tls_rand();
+                #endif
+
+                i %= __atomic_load_n( &lanes.count, __ATOMIC_RELAXED );
 
                 #if !defined(__CFA_NO_STATISTICS__)
@@ -666 +688 @@
         while( query(snzi) ) {
                 // Pick two lists at random
-                int i = __tls_rand() % __atomic_load_n( &lanes.count, __ATOMIC_RELAXED );
-                int j = __tls_rand() % __atomic_load_n( &lanes.count, __ATOMIC_RELAXED );
+                #if defined(BIAS)
+                        unsigned i = __tls_rand();
+                        unsigned j = __tls_rand();
+
+                        if(0 == (i % BIAS)) {
+                                i = i / BIAS;
+                        }
+                        else {
+                                i = ((kernelTLS.this_processor->id * 4) + ((i / BIAS) % 4));
+                                j = ((kernelTLS.this_processor->id * 4) + ((j / BIAS) % 4));
+                        }
+                #else
+                        unsigned i = __tls_rand();
+                        unsigned j = __tls_rand();
+                #endif
+
+                i %= __atomic_load_n( &lanes.count, __ATOMIC_RELAXED );
+                j %= __atomic_load_n( &lanes.count, __ATOMIC_RELAXED );
 
                 // try popping from the 2 picked lists