diff --git a/Sources/LinuxHalSwiftIO/swift_fs.c b/Sources/LinuxHalSwiftIO/swift_fs.c
index be3afef..cbde714 100644
--- a/Sources/LinuxHalSwiftIO/swift_fs.c
+++ b/Sources/LinuxHalSwiftIO/swift_fs.c
@@ -92,8 +92,8 @@ int swifthal_fs_rename(const char *from, char *to) {
 int swifthal_fs_write(void *fp, const void *buf, ssize_t size) {
   size_t nbytes;
 
-  nbytes = fwrite(buf, size, 1, fp);
-  if (nbytes != 1) {
+  nbytes = fwrite(buf, 1, size, fp);
+  if (nbytes == 0) {
     if (ferror(fp))
       return -errno;
     return -EIO;
@@ -105,8 +105,8 @@ int swifthal_fs_write(void *fp, const void *buf, ssize_t size) {
 int swifthal_fs_read(void *fp, void *buf, ssize_t size) {
   size_t nbytes;
 
-  nbytes = fread(buf, size, 1, fp);
-  if (nbytes != 1) {
+  nbytes = fread(buf, 1, size, fp);
+  if (nbytes == 0) {
     if (ferror(fp))
       return -errno;
     if (feof(fp))
diff --git a/Sources/LinuxHalSwiftIO/swift_os.c b/Sources/LinuxHalSwiftIO/swift_os.c
index e55120d..be50481 100644
--- a/Sources/LinuxHalSwiftIO/swift_os.c
+++ b/Sources/LinuxHalSwiftIO/swift_os.c
@@ -69,6 +69,8 @@ void *swifthal_os_task_create(char *name,
   task->p3 = p3;
 
   err = pthread_attr_init(&attr);
+  if (err == 0)
+    err = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
   if (err == 0)
     err = pthread_attr_getschedparam(&attr, &param);
   if (err == 0) {
@@ -151,8 +153,13 @@ static struct timespec *swifthal_timeout_to_timespec(int timeout,
   if (timeout == -1)
     return NULL;
 
-  ts->tv_sec = timeout / 1000;
-  ts->tv_nsec = (timeout % 1000) * NSEC_PER_MSEC;
+  clock_gettime(CLOCK_REALTIME, ts);
+  ts->tv_sec += timeout / 1000;
+  ts->tv_nsec += (timeout % 1000) * NSEC_PER_MSEC;
+  if (ts->tv_nsec >= 1000000000L) {
+    ts->tv_sec += ts->tv_nsec / 1000000000L;
+    ts->tv_nsec %= 1000000000L;
+  }
 
   return ts;
 }
@@ -367,7 +374,12 @@ int swifthal_os_sem_reset(const void *arg) {
   if (sem_getvalue(&sem->sem, &value) != 0)
     return -errno;
   while (value > sem->init_cnt) {
-    if (sem_trywait(&sem->sem) != 0 || sem_getvalue(&sem->sem, &value) != 0)
+    if (sem_trywait(&sem->sem) != 0) {
+      if (errno == EAGAIN)
+        break;
+      return -errno;
+    }
+    if (sem_getvalue(&sem->sem, &value) != 0)
       return -errno;
   }
 
diff --git a/Sources/LinuxHalSwiftIO/swift_platform.c b/Sources/LinuxHalSwiftIO/swift_platform.c
index bf63b5a..59e786c 100644
--- a/Sources/LinuxHalSwiftIO/swift_platform.c
+++ b/Sources/LinuxHalSwiftIO/swift_platform.c
@@ -19,6 +19,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <inttypes.h>
+#include <time.h>
 #include <sys/random.h>
 #ifdef __linux__
 #include <sys/sysinfo.h>
@@ -46,7 +47,7 @@ uint32_t swifthal_hwcycle_get(void) {
 #if __x86_64__
   unsigned a, d;
   asm volatile("rdtsc" : "=a"(a), "=d"(d));
-  return ((uint64_t)a) | (((uint64_t)d) << 32);
+  return a;
 #elif defined(__aarch64__)
   uint64_t val;
   asm volatile("mrs %0, cntvct_el0" : "=r"(val));
@@ -61,7 +62,10 @@ uint32_t swifthal_hwcycle_get(void) {
 }
 
 uint32_t swifthal_hwcycle_to_ns(unsigned int cycles) {
-  return (uint32_t)sysconf(_SC_CLK_TCK);
+  struct timespec tp;
+  if (clock_getres(CLOCK_MONOTONIC, &tp) < 0)
+    return 0;
+  return (uint32_t)((uint64_t)cycles * (tp.tv_sec * 1000000000ULL + tp.tv_nsec));
 }
 
 void swiftHal_randomGet(uint8_t *buf, ssize_t length) {
diff --git a/Sources/LinuxHalSwiftIO/swift_timer.c b/Sources/LinuxHalSwiftIO/swift_timer.c
index 011ffe1..8077dcc 100644
--- a/Sources/LinuxHalSwiftIO/swift_timer.c
+++ b/Sources/LinuxHalSwiftIO/swift_timer.c
@@ -52,6 +52,7 @@ int swifthal_timer_close(void *arg) {
 
   if (timer) {
     dispatch_source_cancel(timer->source);
+    dispatch_resume(timer->source);
     dispatch_release(timer->source);
     free(timer);
     return 0;
@@ -61,15 +62,17 @@ int swifthal_timer_close(void *arg) {
 }
 
 int swifthal_timer_start(void *arg, swift_timer_type_t type, ssize_t period) {
-  const struct swifthal_timer *timer = arg;
+  struct swifthal_timer *timer = arg;
 
   if (timer) {
     uint64_t interval = (uint64_t)period * NSEC_PER_MSEC;
 
+    timer->type = type;
     dispatch_source_set_timer(
         timer->source, dispatch_time(DISPATCH_TIME_NOW, interval),
         (type == SWIFT_TIMER_TYPE_ONESHOT) ? DISPATCH_TIME_FOREVER : interval,
         0);
+    dispatch_resume(timer->source);
     return 0;
   }