Hi

Author: kohler

synch3/GNUmakefile

@@ -1,8 +1,7 @@
 SERVER_PROGRAMS = $(sort $(patsubst %.c,%,$(wildcard serviceserver-??.c)))
-SORT_PROGRAMS = $(sort $(patsubst %.c,%,$(wildcard sort-??.c)))
 SERVICE_PROGRAMS = serviceblaster serviceclient servicelookup serviceserver \
 	$(SERVER_PROGRAMS)
-PROGRAMS = $(SERVICE_PROGRAMS) $(SORT_PROGRAMS)
+PROGRAMS = $(SERVICE_PROGRAMS)
 all: $(PROGRAMS)
 
 O ?= 2
@@ -15,12 +14,9 @@ include ../common/rules.mk
 $(SERVICE_PROGRAMS): %: %.o
 	$(CC) $(CFLAGS) $(O) -o $@ $^
 
-$(SORT_PROGRAMS): %: %.o linereader.o
-	$(CC) $(CFLAGS) $(O) -o $@ $^
-
 
 clean:
-	rm -f *.o *.core $(PROGRAMS)
+	rm -f *.o *.core $(PROGRAMS) sort-[0-9][0-9]
 	rm -rf $(DEPSDIR) *.dSYM
 
 .PHONY: all clean

synch4/.gitignore

@@ -1,2 +1,4 @@
 incr
+incrcmpxchg
+incrlock
 sort-[0-9][0-9]

synch4/GNUmakefile

@@ -1,5 +1,6 @@
 SORT_PROGRAMS = $(sort $(patsubst %.c,%,$(wildcard sort-??.c)))
-PROGRAMS = $(SORT_PROGRAMS) incr
+INCR_PROGRAMS = incr incrlock incrcmpxchg
+PROGRAMS = $(SORT_PROGRAMS) $(INCR_PROGRAMS)
 all: $(PROGRAMS)
 
 O ?= 2
@@ -12,7 +13,7 @@ include ../common/rules.mk
 $(SORT_PROGRAMS): %: %.o linereader.o
 	$(CC) $(CFLAGS) $(O) -o $@ $^
 
-incr: incr.c
+$(INCR_PROGRAMS): %: %.c
 	$(CC) $(CPPFLAGS) $(CFLAGS) $(DEPCFLAGS) -O0 -o $@ $<
 
 

synch4/incr.c

@@ -9,18 +9,11 @@ void* threadfunc(void* arg) {
     return 0;
 }
 
-void* atomic_threadfunc(void* arg) {
-    unsigned* x = (unsigned*) arg;
-    for (int i = 0; i != 10000000; ++i)
-        __sync_fetch_and_add(x, 1);
-    return 0;
-}
-
 int main() {
     pthread_t th[4];
     unsigned n = 0;
     for (int i = 0; i != 4; ++i)
-        pthread_create(&th[i], NULL, atomic_threadfunc, (void*) &n);
+        pthread_create(&th[i], NULL, threadfunc, (void*) &n);
     for (int i = 0; i != 4; ++i)
         pthread_join(th[i], NULL);
     printf("%u\n", n);

synch4/incrcmpxchg.c

@@ -0,0 +1,29 @@
+//! -O0
+#include <pthread.h>
+#include <stdio.h>
+
+void* atomic_threadfunc(void* arg) {
+    unsigned* x = (unsigned*) arg;
+    for (int i = 0; i != 10000000; ++i) {
+        unsigned expected = *x;
+        while (1) {
+            unsigned actual =
+                __sync_val_compare_and_swap(
+                   x, expected, expected + 1);
+            if (actual == expected)
+                break;
+            expected = actual;
+        }
+    }
+    return 0;
+}
+
+int main() {
+    pthread_t th[4];
+    unsigned n = 0;
+    for (int i = 0; i != 4; ++i)
+        pthread_create(&th[i], NULL, atomic_threadfunc, (void*) &n);
+    for (int i = 0; i != 4; ++i)
+        pthread_join(th[i], NULL);
+    printf("%u\n", n);
+}

synch4/incrlock.c

@@ -0,0 +1,20 @@
+//! -O0
+#include <pthread.h>
+#include <stdio.h>
+
+void* atomic_threadfunc(void* arg) {
+    unsigned* x = (unsigned*) arg;
+    for (int i = 0; i != 10000000; ++i)
+        __sync_fetch_and_add(x, 1);
+    return 0;
+}
+
+int main() {
+    pthread_t th[4];
+    unsigned n = 0;
+    for (int i = 0; i != 4; ++i)
+        pthread_create(&th[i], NULL, atomic_threadfunc, (void*) &n);
+    for (int i = 0; i != 4; ++i)
+        pthread_join(th[i], NULL);
+    printf("%u\n", n);
+}

synch4/sort-08.c

@@ -20,7 +20,7 @@ static void* sort_lines(void* arg) {
         pthread_mutex_lock(&mutex);
         if (cur_nthreads < MAX_NTHREADS) {
             method = 1;
-            cur_nthreads += 2;
+            cur_nthreads += 1;
             if (cur_nthreads > max_nthreads)
                 max_nthreads = cur_nthreads;
         } else
@@ -31,19 +31,18 @@ static void* sort_lines(void* arg) {
             lineset left, right;
             split_lines(&left, &right, ls);
 
-            pthread_t left_thread, right_thread;
+            pthread_t left_thread;
             int r1 = pthread_create(&left_thread, NULL, &sort_lines, &left);
-            int r2 = pthread_create(&right_thread, NULL, &sort_lines, &right);
-            assert(r1 == 0 && r2 == 0);
+            assert(r1 == 0);
 
+            sort_lines(&right);
             r1 = pthread_join(left_thread, NULL);
-            r2 = pthread_join(right_thread, NULL);
-            assert(r1 == 0 && r2 == 0);
+            assert(r1 == 0);
 
             merge_lines(ls, &left, &right);
 
             pthread_mutex_lock(&mutex);
-            cur_nthreads -= 2;
+            cur_nthreads -= 1;
             pthread_mutex_unlock(&mutex);
         } else
             qsort(ls->lines, lineset_size(ls), sizeof(line), line_compare);