diff --git a/examples/greenbean.c b/examples/greenbean.c
index d91cac665..e92ceef8f 100644
--- a/examples/greenbean.c
+++ b/examples/greenbean.c
@@ -18,6 +18,7 @@
 #include "libc/fmt/conv.h"
 #include "libc/fmt/itoa.h"
 #include "libc/intrin/kprintf.h"
+#include "libc/intrin/wait0.internal.h"
 #include "libc/limits.h"
 #include "libc/log/check.h"
 #include "libc/log/log.h"
@@ -333,11 +334,17 @@ int main(int argc, char *argv[]) {
   // clean up terminal line
   kprintf("\r\e[K");
 
-  // clean up memory
-  for (i = 0; i < threads; ++i) {
-    if (stack) munmap(stack[i], GetStackSize());
-    if (tls) free(tls[i]);
+  // join the workers
+  // this is how we guarantee stacks are safe to free
+  if (tls && stack) {
+    for (i = 0; i < threads; ++i) {
+      _wait0((int *)(tls[i] + 0x38));
+      munmap(stack[i], GetStackSize());
+      free(tls[i]);
+    }
   }
+
+  // clean up memory
   free(hostips);
   free(stack);
   free(tls);
diff --git a/libc/calls/getloadavg-nt.c b/libc/calls/getloadavg-nt.c
index aad45d409..234bd45fc 100644
--- a/libc/calls/getloadavg-nt.c
+++ b/libc/calls/getloadavg-nt.c
@@ -29,7 +29,7 @@
 
 static int cpus;
 static double load;
-_Alignas(64) static int lock;
+_Alignas(64) static char lock;
 static struct NtFileTime idle1, kern1, user1;
 
 textwindows int sys_getloadavg_nt(double *a, int n) {
diff --git a/libc/intrin/once.h b/libc/intrin/once.h
index 8aa755ad9..52eb74f2d 100644
--- a/libc/intrin/once.h
+++ b/libc/intrin/once.h
@@ -2,20 +2,20 @@
 #define COSMOPOLITAN_LIBC_INTRIN_ONCE_H_
 #include "libc/intrin/spinlock.h"
 
-#define _once(x)                      \
-  ({                                  \
-    typeof(x) oncerc;                 \
-    static bool once;                 \
-    static typeof(oncerc) onceresult; \
-    _Alignas(64) static int oncelock; \
-    _spinlock(&oncelock);             \
-    if (once) {                       \
-      oncerc = onceresult;            \
-    } else {                          \
-      oncerc = onceresult = x;        \
-    }                                 \
-    _spunlock(&oncelock);             \
-    oncerc;                           \
+#define _once(x)                       \
+  ({                                   \
+    typeof(x) oncerc;                  \
+    static bool once;                  \
+    static typeof(oncerc) onceresult;  \
+    _Alignas(64) static char oncelock; \
+    _spinlock(&oncelock);              \
+    if (once) {                        \
+      oncerc = onceresult;             \
+    } else {                           \
+      oncerc = onceresult = x;         \
+    }                                  \
+    _spunlock(&oncelock);              \
+    oncerc;                            \
   })
 
 #endif /* COSMOPOLITAN_LIBC_INTRIN_ONCE_H_ */
diff --git a/libc/intrin/pthread.h b/libc/intrin/pthread.h
index 1c4267424..ac96d8f23 100644
--- a/libc/intrin/pthread.h
+++ b/libc/intrin/pthread.h
@@ -7,9 +7,9 @@ COSMOPOLITAN_C_START_
 
 #define PTHREAD_ONCE_INIT 0
 
-#define PTHREAD_MUTEX_DEFAULT    PTHREAD_MUTEX_RECURSIVE
-#define PTHREAD_MUTEX_NORMAL     0
-#define PTHREAD_MUTEX_RECURSIVE  1
+#define PTHREAD_MUTEX_DEFAULT    PTHREAD_MUTEX_NORMAL
+#define PTHREAD_MUTEX_RECURSIVE  0
+#define PTHREAD_MUTEX_NORMAL     1
 #define PTHREAD_MUTEX_ERRORCHECK 2
 #define PTHREAD_MUTEX_STALLED    0
 #define PTHREAD_MUTEX_ROBUST     1
@@ -26,7 +26,7 @@ typedef int pthread_once_t;
 typedef struct {
   int attr;
   int reent;
-  _Atomic(int) owner;
+  _Atomic(int) lock;
   _Atomic(int) waits;
 } pthread_mutex_t;
 
diff --git a/libc/intrin/pthread_mutex_lock.c b/libc/intrin/pthread_mutex_lock.c
index c2fc26d00..049cb8200 100644
--- a/libc/intrin/pthread_mutex_lock.c
+++ b/libc/intrin/pthread_mutex_lock.c
@@ -29,11 +29,12 @@
  * @return 0 on success, or error number on failure
  */
 int pthread_mutex_lock(pthread_mutex_t *mutex) {
-  int me, owner;
-  unsigned tries;
+  int i, me, owner, tries;
   for (tries = 0, me = gettid();;) {
-    owner = 0;
-    if (atomic_compare_exchange_strong(&mutex->owner, &owner, me)) {
+    owner = atomic_load_explicit(&mutex->lock, memory_order_relaxed);
+    if (!owner && atomic_compare_exchange_weak_explicit(
+                      &mutex->lock, &owner, me, memory_order_acquire,
+                      memory_order_relaxed)) {
       break;
     } else if (owner == me) {
       if (mutex->attr != PTHREAD_MUTEX_ERRORCHECK) {
@@ -42,15 +43,17 @@ int pthread_mutex_lock(pthread_mutex_t *mutex) {
         return EDEADLK;
       }
     }
-    atomic_fetch_add(&mutex->waits, 1);
-    if (!IsLinux() || LinuxFutexWait((void *)&mutex->owner, owner, 0)) {
-      if (++tries & 7) {
-        __builtin_ia32_pause();
-      } else {
-        sched_yield();
+    if (tries < 7) {
+      for (i = 0; i != 1 << tries; i++) {
       }
+      tries++;
+    } else if (IsLinux()) {
+      atomic_fetch_add(&mutex->waits, 1);
+      LinuxFutexWait(&mutex->lock, owner, 0);
+      atomic_fetch_sub(&mutex->waits, 1);
+    } else {
+      sched_yield();
     }
-    atomic_fetch_sub(&mutex->waits, 1);
   }
   ++mutex->reent;
   return 0;
diff --git a/libc/intrin/pthread_mutex_trylock.c b/libc/intrin/pthread_mutex_trylock.c
index 20063a856..8e995a4d4 100644
--- a/libc/intrin/pthread_mutex_trylock.c
+++ b/libc/intrin/pthread_mutex_trylock.c
@@ -29,7 +29,7 @@ int pthread_mutex_trylock(pthread_mutex_t *mutex) {
   int rc, me, owner;
   me = gettid();
   owner = 0;
-  if (!atomic_compare_exchange_strong(&mutex->owner, &owner, me) &&
+  if (!atomic_compare_exchange_strong(&mutex->lock, &owner, me) &&
       owner == me) {
     rc = 0;
     ++mutex->reent;
diff --git a/libc/intrin/pthread_mutex_unlock.c b/libc/intrin/pthread_mutex_unlock.c
index 3a9238cd8..265c507c0 100644
--- a/libc/intrin/pthread_mutex_unlock.c
+++ b/libc/intrin/pthread_mutex_unlock.c
@@ -31,14 +31,14 @@
  */
 int pthread_mutex_unlock(pthread_mutex_t *mutex) {
   int owner;
-  if (mutex->attr == PTHREAD_MUTEX_ERRORCHECK && mutex->owner != gettid()) {
+  if (mutex->attr == PTHREAD_MUTEX_ERRORCHECK && mutex->lock != gettid()) {
     return EPERM;
   }
   if (!--mutex->reent) {
-    atomic_store_explicit(&mutex->owner, 0, memory_order_relaxed);
+    atomic_store_explicit(&mutex->lock, 0, memory_order_relaxed);
     if (IsLinux() &&
         atomic_load_explicit(&mutex->waits, memory_order_acquire)) {
-      LinuxFutexWake(&mutex->owner, 1);
+      LinuxFutexWake(&mutex->lock, 1);
     }
   }
   return 0;
diff --git a/libc/intrin/spinlock.h b/libc/intrin/spinlock.h
index 8ee2690cb..9294432b4 100644
--- a/libc/intrin/spinlock.h
+++ b/libc/intrin/spinlock.h
@@ -20,20 +20,19 @@
     __atomic_store(__lock, &__x, __ATOMIC_RELEASE); \
   })
 
-#define _spinlock_tiny(lock)        \
-  ({                                \
-    autotype(lock) __lock = (lock); \
-    while (_trylock(__lock)) {      \
-      __builtin_ia32_pause();       \
-    }                               \
-    0;                              \
+#define _spinlock_tiny(lock)  \
+  ({                          \
+    while (_trylock(lock)) {  \
+      __builtin_ia32_pause(); \
+    }                         \
+    0;                        \
   })
 
 #define _spinlock_cooperative(lock)                  \
   ({                                                 \
-    autotype(lock) __lock = (lock);                  \
-    typeof(*__lock) __x;                             \
+    char __x;                                        \
     unsigned __tries = 0;                            \
+    char *__lock = (lock);                           \
     for (;;) {                                       \
       __atomic_load(__lock, &__x, __ATOMIC_RELAXED); \
       if (!__x && !_trylock(__lock)) {               \
@@ -47,6 +46,27 @@
     0;                                               \
   })
 
+#define _spinlock_cooperative_(lock)                 \
+  ({                                                 \
+    char __x;                                        \
+    volatile int __i;                                \
+    unsigned __tries = 0;                            \
+    char *__lock = (lock);                           \
+    for (;;) {                                       \
+      __atomic_load(__lock, &__x, __ATOMIC_RELAXED); \
+      if (!__x && !_trylock(__lock)) {               \
+        break;                                       \
+      } else if (__tries < 7) {                      \
+        for (__i = 0; __i != 1 << __tries; __i++) {  \
+        }                                            \
+        __tries++;                                   \
+      } else {                                       \
+        _spinlock_yield();                           \
+      }                                              \
+    }                                                \
+    0;                                               \
+  })
+
 #define _trylock(lock) __atomic_test_and_set(lock, __ATOMIC_SEQ_CST)
 
 void _spinlock_yield(void);
diff --git a/libc/intrin/wait0.internal.h b/libc/intrin/wait0.internal.h
new file mode 100644
index 000000000..28d104629
--- /dev/null
+++ b/libc/intrin/wait0.internal.h
@@ -0,0 +1,20 @@
+#ifndef COSMOPOLITAN_LIBC_INTRIN_WAIT0_H_
+#define COSMOPOLITAN_LIBC_INTRIN_WAIT0_H_
+#include "libc/bits/atomic.h"
+#include "libc/calls/calls.h"
+#include "libc/dce.h"
+#include "libc/linux/futex.h"
+
+#define _wait0(ptid)                                               \
+  do {                                                             \
+    int x;                                                         \
+    if (!(x = atomic_load_explicit(ptid, memory_order_relaxed))) { \
+      break;                                                       \
+    } else if (IsLinux()) {                                        \
+      LinuxFutexWait(ptid, x, 0);                                  \
+    } else {                                                       \
+      sched_yield();                                               \
+    }                                                              \
+  } while (1)
+
+#endif /* COSMOPOLITAN_LIBC_INTRIN_WAIT0_H_ */
diff --git a/libc/nt/gdi32/DdEntry0.s b/libc/nt/gdi32/DdEntry0.s
deleted file mode 100644
index b54a028da..000000000
--- a/libc/nt/gdi32/DdEntry0.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry0,DdEntry0,1324
diff --git a/libc/nt/gdi32/DdEntry1.s b/libc/nt/gdi32/DdEntry1.s
deleted file mode 100644
index 88ed6fc32..000000000
--- a/libc/nt/gdi32/DdEntry1.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry1,DdEntry1,1325
diff --git a/libc/nt/gdi32/DdEntry10.s b/libc/nt/gdi32/DdEntry10.s
deleted file mode 100644
index 9d58c5a92..000000000
--- a/libc/nt/gdi32/DdEntry10.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry10,DdEntry10,1326
diff --git a/libc/nt/gdi32/DdEntry11.s b/libc/nt/gdi32/DdEntry11.s
deleted file mode 100644
index 8193ae74a..000000000
--- a/libc/nt/gdi32/DdEntry11.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry11,DdEntry11,1327
diff --git a/libc/nt/gdi32/DdEntry12.s b/libc/nt/gdi32/DdEntry12.s
deleted file mode 100644
index ef5706740..000000000
--- a/libc/nt/gdi32/DdEntry12.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry12,DdEntry12,1328
diff --git a/libc/nt/gdi32/DdEntry13.s b/libc/nt/gdi32/DdEntry13.s
deleted file mode 100644
index fc13c41ad..000000000
--- a/libc/nt/gdi32/DdEntry13.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry13,DdEntry13,1329
diff --git a/libc/nt/gdi32/DdEntry14.s b/libc/nt/gdi32/DdEntry14.s
deleted file mode 100644
index 4b8d188be..000000000
--- a/libc/nt/gdi32/DdEntry14.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry14,DdEntry14,1330
diff --git a/libc/nt/gdi32/DdEntry15.s b/libc/nt/gdi32/DdEntry15.s
deleted file mode 100644
index f95c54f2b..000000000
--- a/libc/nt/gdi32/DdEntry15.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry15,DdEntry15,1331
diff --git a/libc/nt/gdi32/DdEntry16.s b/libc/nt/gdi32/DdEntry16.s
deleted file mode 100644
index 2ceb8985c..000000000
--- a/libc/nt/gdi32/DdEntry16.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry16,DdEntry16,1332
diff --git a/libc/nt/gdi32/DdEntry17.s b/libc/nt/gdi32/DdEntry17.s
deleted file mode 100644
index 2a7648d7a..000000000
--- a/libc/nt/gdi32/DdEntry17.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry17,DdEntry17,1333
diff --git a/libc/nt/gdi32/DdEntry18.s b/libc/nt/gdi32/DdEntry18.s
deleted file mode 100644
index 095275a09..000000000
--- a/libc/nt/gdi32/DdEntry18.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry18,DdEntry18,1334
diff --git a/libc/nt/gdi32/DdEntry19.s b/libc/nt/gdi32/DdEntry19.s
deleted file mode 100644
index 8222d138d..000000000
--- a/libc/nt/gdi32/DdEntry19.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry19,DdEntry19,1335
diff --git a/libc/nt/gdi32/DdEntry2.s b/libc/nt/gdi32/DdEntry2.s
deleted file mode 100644
index b02cd8443..000000000
--- a/libc/nt/gdi32/DdEntry2.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry2,DdEntry2,1336
diff --git a/libc/nt/gdi32/DdEntry20.s b/libc/nt/gdi32/DdEntry20.s
deleted file mode 100644
index 38e796a53..000000000
--- a/libc/nt/gdi32/DdEntry20.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry20,DdEntry20,1337
diff --git a/libc/nt/gdi32/DdEntry21.s b/libc/nt/gdi32/DdEntry21.s
deleted file mode 100644
index 48d29c6a7..000000000
--- a/libc/nt/gdi32/DdEntry21.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry21,DdEntry21,1338
diff --git a/libc/nt/gdi32/DdEntry22.s b/libc/nt/gdi32/DdEntry22.s
deleted file mode 100644
index 50ce1b7ce..000000000
--- a/libc/nt/gdi32/DdEntry22.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry22,DdEntry22,1339
diff --git a/libc/nt/gdi32/DdEntry23.s b/libc/nt/gdi32/DdEntry23.s
deleted file mode 100644
index 9626d3758..000000000
--- a/libc/nt/gdi32/DdEntry23.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry23,DdEntry23,1340
diff --git a/libc/nt/gdi32/DdEntry24.s b/libc/nt/gdi32/DdEntry24.s
deleted file mode 100644
index e89d76aab..000000000
--- a/libc/nt/gdi32/DdEntry24.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry24,DdEntry24,1341
diff --git a/libc/nt/gdi32/DdEntry25.s b/libc/nt/gdi32/DdEntry25.s
deleted file mode 100644
index cc1d638cd..000000000
--- a/libc/nt/gdi32/DdEntry25.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry25,DdEntry25,1342
diff --git a/libc/nt/gdi32/DdEntry26.s b/libc/nt/gdi32/DdEntry26.s
deleted file mode 100644
index 3c7949dae..000000000
--- a/libc/nt/gdi32/DdEntry26.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry26,DdEntry26,1343
diff --git a/libc/nt/gdi32/DdEntry27.s b/libc/nt/gdi32/DdEntry27.s
deleted file mode 100644
index d088ad12e..000000000
--- a/libc/nt/gdi32/DdEntry27.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry27,DdEntry27,1344
diff --git a/libc/nt/gdi32/DdEntry28.s b/libc/nt/gdi32/DdEntry28.s
deleted file mode 100644
index 4f9a21a79..000000000
--- a/libc/nt/gdi32/DdEntry28.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry28,DdEntry28,1345
diff --git a/libc/nt/gdi32/DdEntry29.s b/libc/nt/gdi32/DdEntry29.s
deleted file mode 100644
index 3b1bd4f13..000000000
--- a/libc/nt/gdi32/DdEntry29.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry29,DdEntry29,1346
diff --git a/libc/nt/gdi32/DdEntry3.s b/libc/nt/gdi32/DdEntry3.s
deleted file mode 100644
index 3d69c6140..000000000
--- a/libc/nt/gdi32/DdEntry3.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry3,DdEntry3,1347
diff --git a/libc/nt/gdi32/DdEntry30.s b/libc/nt/gdi32/DdEntry30.s
deleted file mode 100644
index 403a112cc..000000000
--- a/libc/nt/gdi32/DdEntry30.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry30,DdEntry30,1348
diff --git a/libc/nt/gdi32/DdEntry31.s b/libc/nt/gdi32/DdEntry31.s
deleted file mode 100644
index 462b58f31..000000000
--- a/libc/nt/gdi32/DdEntry31.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry31,DdEntry31,1349
diff --git a/libc/nt/gdi32/DdEntry32.s b/libc/nt/gdi32/DdEntry32.s
deleted file mode 100644
index b87b8b8d9..000000000
--- a/libc/nt/gdi32/DdEntry32.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry32,DdEntry32,1350
diff --git a/libc/nt/gdi32/DdEntry33.s b/libc/nt/gdi32/DdEntry33.s
deleted file mode 100644
index 84ce424fb..000000000
--- a/libc/nt/gdi32/DdEntry33.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry33,DdEntry33,1351
diff --git a/libc/nt/gdi32/DdEntry34.s b/libc/nt/gdi32/DdEntry34.s
deleted file mode 100644
index 52abe2753..000000000
--- a/libc/nt/gdi32/DdEntry34.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry34,DdEntry34,1352
diff --git a/libc/nt/gdi32/DdEntry35.s b/libc/nt/gdi32/DdEntry35.s
deleted file mode 100644
index 49b45d222..000000000
--- a/libc/nt/gdi32/DdEntry35.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry35,DdEntry35,1353
diff --git a/libc/nt/gdi32/DdEntry36.s b/libc/nt/gdi32/DdEntry36.s
deleted file mode 100644
index 3c51c1529..000000000
--- a/libc/nt/gdi32/DdEntry36.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry36,DdEntry36,1354
diff --git a/libc/nt/gdi32/DdEntry37.s b/libc/nt/gdi32/DdEntry37.s
deleted file mode 100644
index e2eadb885..000000000
--- a/libc/nt/gdi32/DdEntry37.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry37,DdEntry37,1355
diff --git a/libc/nt/gdi32/DdEntry38.s b/libc/nt/gdi32/DdEntry38.s
deleted file mode 100644
index 281b331ed..000000000
--- a/libc/nt/gdi32/DdEntry38.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry38,DdEntry38,1356
diff --git a/libc/nt/gdi32/DdEntry39.s b/libc/nt/gdi32/DdEntry39.s
deleted file mode 100644
index 4b9e36225..000000000
--- a/libc/nt/gdi32/DdEntry39.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry39,DdEntry39,1357
diff --git a/libc/nt/gdi32/DdEntry4.s b/libc/nt/gdi32/DdEntry4.s
deleted file mode 100644
index d729bdfcb..000000000
--- a/libc/nt/gdi32/DdEntry4.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry4,DdEntry4,1358
diff --git a/libc/nt/gdi32/DdEntry40.s b/libc/nt/gdi32/DdEntry40.s
deleted file mode 100644
index a8dc142e7..000000000
--- a/libc/nt/gdi32/DdEntry40.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry40,DdEntry40,1359
diff --git a/libc/nt/gdi32/DdEntry41.s b/libc/nt/gdi32/DdEntry41.s
deleted file mode 100644
index aaffe57f6..000000000
--- a/libc/nt/gdi32/DdEntry41.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry41,DdEntry41,1360
diff --git a/libc/nt/gdi32/DdEntry42.s b/libc/nt/gdi32/DdEntry42.s
deleted file mode 100644
index d146ea69b..000000000
--- a/libc/nt/gdi32/DdEntry42.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry42,DdEntry42,1361
diff --git a/libc/nt/gdi32/DdEntry43.s b/libc/nt/gdi32/DdEntry43.s
deleted file mode 100644
index 1a67232c5..000000000
--- a/libc/nt/gdi32/DdEntry43.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry43,DdEntry43,1362
diff --git a/libc/nt/gdi32/DdEntry44.s b/libc/nt/gdi32/DdEntry44.s
deleted file mode 100644
index fe7a1030e..000000000
--- a/libc/nt/gdi32/DdEntry44.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry44,DdEntry44,1363
diff --git a/libc/nt/gdi32/DdEntry45.s b/libc/nt/gdi32/DdEntry45.s
deleted file mode 100644
index b853411b8..000000000
--- a/libc/nt/gdi32/DdEntry45.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry45,DdEntry45,1364
diff --git a/libc/nt/gdi32/DdEntry46.s b/libc/nt/gdi32/DdEntry46.s
deleted file mode 100644
index 9ac43e3c5..000000000
--- a/libc/nt/gdi32/DdEntry46.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry46,DdEntry46,1365
diff --git a/libc/nt/gdi32/DdEntry47.s b/libc/nt/gdi32/DdEntry47.s
deleted file mode 100644
index 5fb90a3b5..000000000
--- a/libc/nt/gdi32/DdEntry47.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry47,DdEntry47,1366
diff --git a/libc/nt/gdi32/DdEntry48.s b/libc/nt/gdi32/DdEntry48.s
deleted file mode 100644
index 40be41e0c..000000000
--- a/libc/nt/gdi32/DdEntry48.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry48,DdEntry48,1367
diff --git a/libc/nt/gdi32/DdEntry49.s b/libc/nt/gdi32/DdEntry49.s
deleted file mode 100644
index 621622130..000000000
--- a/libc/nt/gdi32/DdEntry49.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry49,DdEntry49,1368
diff --git a/libc/nt/gdi32/DdEntry5.s b/libc/nt/gdi32/DdEntry5.s
deleted file mode 100644
index 154167112..000000000
--- a/libc/nt/gdi32/DdEntry5.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry5,DdEntry5,1369
diff --git a/libc/nt/gdi32/DdEntry50.s b/libc/nt/gdi32/DdEntry50.s
deleted file mode 100644
index 6fabf567d..000000000
--- a/libc/nt/gdi32/DdEntry50.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry50,DdEntry50,1370
diff --git a/libc/nt/gdi32/DdEntry51.s b/libc/nt/gdi32/DdEntry51.s
deleted file mode 100644
index e5d6efc39..000000000
--- a/libc/nt/gdi32/DdEntry51.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry51,DdEntry51,1371
diff --git a/libc/nt/gdi32/DdEntry52.s b/libc/nt/gdi32/DdEntry52.s
deleted file mode 100644
index ffb246a5e..000000000
--- a/libc/nt/gdi32/DdEntry52.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry52,DdEntry52,1372
diff --git a/libc/nt/gdi32/DdEntry53.s b/libc/nt/gdi32/DdEntry53.s
deleted file mode 100644
index cb15fea97..000000000
--- a/libc/nt/gdi32/DdEntry53.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry53,DdEntry53,1373
diff --git a/libc/nt/gdi32/DdEntry54.s b/libc/nt/gdi32/DdEntry54.s
deleted file mode 100644
index 2cd8d68e8..000000000
--- a/libc/nt/gdi32/DdEntry54.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry54,DdEntry54,1374
diff --git a/libc/nt/gdi32/DdEntry55.s b/libc/nt/gdi32/DdEntry55.s
deleted file mode 100644
index bd3d28ce9..000000000
--- a/libc/nt/gdi32/DdEntry55.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry55,DdEntry55,1375
diff --git a/libc/nt/gdi32/DdEntry56.s b/libc/nt/gdi32/DdEntry56.s
deleted file mode 100644
index ddae132c7..000000000
--- a/libc/nt/gdi32/DdEntry56.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry56,DdEntry56,1376
diff --git a/libc/nt/gdi32/DdEntry6.s b/libc/nt/gdi32/DdEntry6.s
deleted file mode 100644
index 100809bfb..000000000
--- a/libc/nt/gdi32/DdEntry6.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry6,DdEntry6,1377
diff --git a/libc/nt/gdi32/DdEntry7.s b/libc/nt/gdi32/DdEntry7.s
deleted file mode 100644
index 20ad1fc55..000000000
--- a/libc/nt/gdi32/DdEntry7.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry7,DdEntry7,1378
diff --git a/libc/nt/gdi32/DdEntry8.s b/libc/nt/gdi32/DdEntry8.s
deleted file mode 100644
index 3502030d0..000000000
--- a/libc/nt/gdi32/DdEntry8.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry8,DdEntry8,1379
diff --git a/libc/nt/gdi32/DdEntry9.s b/libc/nt/gdi32/DdEntry9.s
deleted file mode 100644
index 265418dfc..000000000
--- a/libc/nt/gdi32/DdEntry9.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_DdEntry9,DdEntry9,1380
diff --git a/libc/nt/gdi32/GdiEntry1.s b/libc/nt/gdi32/GdiEntry1.s
deleted file mode 100644
index e21fb95cb..000000000
--- a/libc/nt/gdi32/GdiEntry1.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry1,GdiEntry1,1518
diff --git a/libc/nt/gdi32/GdiEntry10.s b/libc/nt/gdi32/GdiEntry10.s
deleted file mode 100644
index 865d6b48f..000000000
--- a/libc/nt/gdi32/GdiEntry10.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry10,GdiEntry10,1519
diff --git a/libc/nt/gdi32/GdiEntry11.s b/libc/nt/gdi32/GdiEntry11.s
deleted file mode 100644
index 297be2389..000000000
--- a/libc/nt/gdi32/GdiEntry11.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry11,GdiEntry11,1520
diff --git a/libc/nt/gdi32/GdiEntry12.s b/libc/nt/gdi32/GdiEntry12.s
deleted file mode 100644
index e7d9ddcbc..000000000
--- a/libc/nt/gdi32/GdiEntry12.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry12,GdiEntry12,1521
diff --git a/libc/nt/gdi32/GdiEntry13.s b/libc/nt/gdi32/GdiEntry13.s
deleted file mode 100644
index cd17cedc2..000000000
--- a/libc/nt/gdi32/GdiEntry13.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry13,GdiEntry13,1522
diff --git a/libc/nt/gdi32/GdiEntry14.s b/libc/nt/gdi32/GdiEntry14.s
deleted file mode 100644
index f2892ec2c..000000000
--- a/libc/nt/gdi32/GdiEntry14.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry14,GdiEntry14,1523
diff --git a/libc/nt/gdi32/GdiEntry15.s b/libc/nt/gdi32/GdiEntry15.s
deleted file mode 100644
index 81e3b1dca..000000000
--- a/libc/nt/gdi32/GdiEntry15.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry15,GdiEntry15,1524
diff --git a/libc/nt/gdi32/GdiEntry16.s b/libc/nt/gdi32/GdiEntry16.s
deleted file mode 100644
index 394669389..000000000
--- a/libc/nt/gdi32/GdiEntry16.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry16,GdiEntry16,1525
diff --git a/libc/nt/gdi32/GdiEntry2.s b/libc/nt/gdi32/GdiEntry2.s
deleted file mode 100644
index 20c3d8e5f..000000000
--- a/libc/nt/gdi32/GdiEntry2.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry2,GdiEntry2,1526
diff --git a/libc/nt/gdi32/GdiEntry3.s b/libc/nt/gdi32/GdiEntry3.s
deleted file mode 100644
index 07951818d..000000000
--- a/libc/nt/gdi32/GdiEntry3.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry3,GdiEntry3,1527
diff --git a/libc/nt/gdi32/GdiEntry4.s b/libc/nt/gdi32/GdiEntry4.s
deleted file mode 100644
index 0625863e9..000000000
--- a/libc/nt/gdi32/GdiEntry4.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry4,GdiEntry4,1528
diff --git a/libc/nt/gdi32/GdiEntry5.s b/libc/nt/gdi32/GdiEntry5.s
deleted file mode 100644
index 833a80134..000000000
--- a/libc/nt/gdi32/GdiEntry5.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry5,GdiEntry5,1529
diff --git a/libc/nt/gdi32/GdiEntry6.s b/libc/nt/gdi32/GdiEntry6.s
deleted file mode 100644
index b814bf101..000000000
--- a/libc/nt/gdi32/GdiEntry6.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry6,GdiEntry6,1530
diff --git a/libc/nt/gdi32/GdiEntry7.s b/libc/nt/gdi32/GdiEntry7.s
deleted file mode 100644
index 9bd13d5e3..000000000
--- a/libc/nt/gdi32/GdiEntry7.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry7,GdiEntry7,1531
diff --git a/libc/nt/gdi32/GdiEntry8.s b/libc/nt/gdi32/GdiEntry8.s
deleted file mode 100644
index 2de940358..000000000
--- a/libc/nt/gdi32/GdiEntry8.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry8,GdiEntry8,1532
diff --git a/libc/nt/gdi32/GdiEntry9.s b/libc/nt/gdi32/GdiEntry9.s
deleted file mode 100644
index 43944a292..000000000
--- a/libc/nt/gdi32/GdiEntry9.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.include "o/libc/nt/codegen.inc"
-.imp	gdi32,__imp_GdiEntry9,GdiEntry9,1533
diff --git a/libc/runtime/clone.c b/libc/runtime/clone.c
index 88f7b87b6..73a8e746a 100644
--- a/libc/runtime/clone.c
+++ b/libc/runtime/clone.c
@@ -63,7 +63,7 @@ struct CloneArgs {
     int64_t tid64;
   };
   union {
-    int lock;
+    char lock;
     void *pstack;
   };
   int *ctid;
diff --git a/libc/testlib/showerror.c b/libc/testlib/showerror.c
index 680ee7ef6..320e2facc 100644
--- a/libc/testlib/showerror.c
+++ b/libc/testlib/showerror.c
@@ -32,7 +32,7 @@ const char *testlib_showerror_func;
 const char *testlib_showerror_isfatal;
 const char *testlib_showerror_macro;
 const char *testlib_showerror_symbol;
-_Alignas(64) static int testlib_showerror_lock;
+_Alignas(64) static char testlib_showerror_lock;
 
 testonly void testlib_showerror(const char *file, int line, const char *func,
                                 const char *method, const char *symbol,
diff --git a/libc/thread/join.c b/libc/thread/join.c
index c07e98482..05dedb134 100644
--- a/libc/thread/join.c
+++ b/libc/thread/join.c
@@ -22,7 +22,6 @@
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/intrin/asan.internal.h"
-#include "libc/intrin/spinlock.h"
 #include "libc/runtime/runtime.h"
 #include "libc/str/str.h"
 #include "libc/sysv/consts/futex.h"
diff --git a/test/libc/calls/reservefd_test.c b/test/libc/calls/reservefd_test.c
index 5c2a314f7..ace2bb5be 100644
--- a/test/libc/calls/reservefd_test.c
+++ b/test/libc/calls/reservefd_test.c
@@ -25,6 +25,7 @@
 #include "libc/errno.h"
 #include "libc/intrin/kprintf.h"
 #include "libc/intrin/spinlock.h"
+#include "libc/intrin/wait0.internal.h"
 #include "libc/macros.internal.h"
 #include "libc/nexgen32e/threaded.h"
 #include "libc/rand/rand.h"
@@ -128,7 +129,7 @@ TEST(reservefd, tortureTest) {
           (int *)(tls[i] + 0x38));
   }
   for (i = 0; i < THREADS; ++i) {
-    _spinlock((int *)(tls[i] + 0x38));
+    _wait0((int *)(tls[i] + 0x38));
   }
   // EXPECT_SYS(0, 0, sigaction(SIGALRM, &oldsa, 0));
   // EXPECT_SYS(0, 0, setitimer(ITIMER_REAL, &oldit, 0));
diff --git a/test/libc/intrin/pthread_mutex_lock_test.c b/test/libc/intrin/pthread_mutex_lock_test.c
index 79d0a6c36..4cfc7ea3f 100644
--- a/test/libc/intrin/pthread_mutex_lock_test.c
+++ b/test/libc/intrin/pthread_mutex_lock_test.c
@@ -22,7 +22,9 @@
 #include "libc/intrin/kprintf.h"
 #include "libc/intrin/pthread.h"
 #include "libc/intrin/spinlock.h"
+#include "libc/intrin/wait0.internal.h"
 #include "libc/nexgen32e/threaded.h"
+#include "libc/runtime/internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/runtime/stack.h"
 #include "libc/sysv/consts/clone.h"
@@ -32,24 +34,23 @@
 #include "libc/testlib/testlib.h"
 #include "libc/thread/thread.h"
 
-static char tls[64];
+#define THREADS    8
+#define ITERATIONS 512
 
-int PutProcessInThreadingMode(void *p) {
-  return 0;
-}
+char *stack[THREADS];
+char tls[THREADS][64];
 
-void SetUp(void) {
-  clone(PutProcessInThreadingMode,
-        mmap(0, GetStackSize(), PROT_READ | PROT_WRITE,
-             MAP_STACK | MAP_ANONYMOUS, -1, 0),
-        GetStackSize(),
-        CLONE_THREAD | CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND |
-            CLONE_SETTLS,
-        0, 0, __initialize_tls(tls), sizeof(tls), 0);
+__attribute__((__constructor__)) void init(void) {
+  __enable_tls();
+  __enable_threads();
 }
 
 TEST(pthread_mutex_lock, normal) {
   pthread_mutex_t lock;
+  pthread_mutexattr_t attr;
+  ASSERT_EQ(0, pthread_mutexattr_init(&attr));
+  ASSERT_EQ(0, pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL));
+  ASSERT_EQ(0, pthread_mutex_init(&lock, &attr));
   ASSERT_EQ(0, pthread_mutex_init(&lock, 0));
   ASSERT_EQ(0, pthread_mutex_lock(&lock));
   ASSERT_EQ(0, pthread_mutex_unlock(&lock));
@@ -89,6 +90,78 @@ TEST(pthread_mutex_lock, errorcheck) {
   ASSERT_EQ(0, pthread_mutexattr_destroy(&attr));
 }
 
+int count;
+_Atomic(int) finished;
+_Alignas(64) char slock;
+pthread_mutex_t lock;
+
+int MutexWorker(void *p) {
+  int i;
+  for (i = 0; i < ITERATIONS; ++i) {
+    pthread_mutex_lock(&lock);
+    ++count;
+    pthread_mutex_unlock(&lock);
+  }
+  return 0;
+}
+
+TEST(pthread_mutex_lock, contention) {
+  int i;
+  count = 0;
+  for (i = 0; i < THREADS; ++i) {
+    clone(MutexWorker,
+          (stack[i] = mmap(0, GetStackSize(), PROT_READ | PROT_WRITE,
+                           MAP_STACK | MAP_ANONYMOUS, -1, 0)),
+          GetStackSize(),
+          CLONE_THREAD | CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND |
+              CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | CLONE_SETTLS,
+          0, 0, __initialize_tls(tls[i]), sizeof(tls[i]),
+          (int *)(tls[i] + 0x38));
+  }
+  for (i = 0; i < THREADS; ++i) {
+    _wait0((int *)(tls[i] + 0x38));
+  }
+  ASSERT_EQ(THREADS * ITERATIONS, count);
+  for (i = 0; i < THREADS; ++i) {
+    munmap(stack[i], GetStackSize());
+  }
+}
+
+int SpinlockWorker(void *p) {
+  int i;
+  for (i = 0; i < ITERATIONS; ++i) {
+    _spinlock(&slock);
+    ++count;
+    _spunlock(&slock);
+  }
+  ++finished;
+  return 0;
+}
+
+TEST(_spinlock, contention) {
+  int i;
+  count = 0;
+  finished = 0;
+  for (i = 0; i < THREADS; ++i) {
+    clone(SpinlockWorker,
+          (stack[i] = mmap(0, GetStackSize(), PROT_READ | PROT_WRITE,
+                           MAP_STACK | MAP_ANONYMOUS, -1, 0)),
+          GetStackSize(),
+          CLONE_THREAD | CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND |
+              CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | CLONE_SETTLS,
+          0, 0, __initialize_tls(tls[i]), sizeof(tls[i]),
+          (int *)(tls[i] + 0x38));
+  }
+  for (i = 0; i < THREADS; ++i) {
+    _wait0((int *)(tls[i] + 0x38));
+  }
+  ASSERT_EQ(THREADS, finished);
+  ASSERT_EQ(THREADS * ITERATIONS, count);
+  for (i = 0; i < THREADS; ++i) {
+    munmap(stack[i], GetStackSize());
+  }
+}
+
 BENCH(pthread_mutex_lock, bench) {
   char schar = 0;
   pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
@@ -100,4 +173,6 @@ BENCH(pthread_mutex_lock, bench) {
            (_spinlock_tiny(&schar), _spunlock(&schar)));
   EZBENCH2("_spinlock_coop", donothing,
            (_spinlock_cooperative(&schar), _spunlock(&schar)));
+  EZBENCH2("content mut", donothing, pthread_mutex_lock_contention());
+  EZBENCH2("content spin", donothing, _spinlock_contention());
 }
diff --git a/test/libc/runtime/clone_test.c b/test/libc/runtime/clone_test.c
index 5fd0384a1..25fcb6b2d 100644
--- a/test/libc/runtime/clone_test.c
+++ b/test/libc/runtime/clone_test.c
@@ -21,6 +21,7 @@
 #include "libc/errno.h"
 #include "libc/intrin/kprintf.h"
 #include "libc/intrin/spinlock.h"
+#include "libc/intrin/wait0.internal.h"
 #include "libc/log/backtrace.internal.h"
 #include "libc/mem/mem.h"
 #include "libc/nexgen32e/gettls.h"
@@ -102,14 +103,13 @@ int CloneTest1(void *arg) {
 TEST(clone, test1) {
   int ptid = 0;
   *childetid = -1;
-  _seizelock(childetid, -1);
   ASSERT_NE(-1, (tid = clone(CloneTest1, stack, GetStackSize(),
                              CLONE_THREAD | CLONE_VM | CLONE_FS | CLONE_FILES |
                                  CLONE_SIGHAND | CLONE_PARENT_SETTID |
                                  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID |
                                  CLONE_SETTLS,
                              (void *)23, &ptid, tls, 64, childetid)));
-  _spinlock(childetid);  // CLONE_CHILD_CLEARTID
+  _wait0(childetid);  // CLONE_CHILD_CLEARTID
   ASSERT_NE(gettid(), tid);
   ASSERT_EQ(tid, ptid);
   ASSERT_EQ(42, x);
@@ -174,7 +174,7 @@ TEST(clone, tlsSystemCallsErrno_wontClobberMainThreadBecauseTls) {
   }
   sysbarrier = 1;
   for (i = 0; i < 8; ++i) {
-    _spinlock((int *)(tls[i] + 0x38));
+    _wait0((int *)(tls[i] + 0x38));
     free(tls[i]);
     munmap(stack[i], GetStackSize());
   }
diff --git a/test/libc/stdio/dtoa_test.c b/test/libc/stdio/dtoa_test.c
index 8d2a315d6..1ccd2a6d9 100644
--- a/test/libc/stdio/dtoa_test.c
+++ b/test/libc/stdio/dtoa_test.c
@@ -19,6 +19,7 @@
 #include "libc/calls/calls.h"
 #include "libc/fmt/fmt.h"
 #include "libc/intrin/spinlock.h"
+#include "libc/intrin/wait0.internal.h"
 #include "libc/math.h"
 #include "libc/runtime/stack.h"
 #include "libc/stdio/stdio.h"
@@ -71,7 +72,7 @@ TEST(dtoa, test) {
           (int *)(tls[i] + 0x38));
   }
   for (i = 0; i < THREADS; ++i) {
-    _spinlock((int *)(tls[i] + 0x38));
+    _wait0((int *)(tls[i] + 0x38));
   }
 }
 
diff --git a/tool/build/mkdeps.c b/tool/build/mkdeps.c
index a27647aef..7501a3cfc 100644
--- a/tool/build/mkdeps.c
+++ b/tool/build/mkdeps.c
@@ -30,6 +30,7 @@
 #include "libc/fmt/fmt.h"
 #include "libc/intrin/kprintf.h"
 #include "libc/intrin/spinlock.h"
+#include "libc/intrin/wait0.internal.h"
 #include "libc/log/check.h"
 #include "libc/log/log.h"
 #include "libc/macros.internal.h"
@@ -131,10 +132,10 @@ struct Sauce *sauces;
 struct Strings strings;
 struct Sources sources;
 const char *buildroot;
-_Alignas(64) int galock;
-_Alignas(64) int readlock;
-_Alignas(64) int writelock;
-_Alignas(64) int reportlock;
+_Alignas(64) char galock;
+_Alignas(64) char readlock;
+_Alignas(64) char writelock;
+_Alignas(64) char reportlock;
 
 unsigned Hash(const void *s, size_t l) {
   return max(1, crc32c(0, s, l));
@@ -316,7 +317,7 @@ void LoadRelationships(int argc, char *argv[]) {
     }
   }
   for (i = 0; i < threads; ++i) {
-    _spinlock((int *)(tls[i] + 0x38));
+    _wait0((int *)(tls[i] + 0x38));
   }
   getargs_destroy(&ga);
 }
@@ -431,7 +432,7 @@ void Explore(void) {
     }
   }
   for (i = 0; i < threads; ++i) {
-    _spinlock((int *)(tls[i] + 0x38));
+    _wait0((int *)(tls[i] + 0x38));
   }
 }
 
diff --git a/tool/build/wastecpu.c b/tool/build/wastecpu.c
index bce1ea198..fbb1d86e1 100644
--- a/tool/build/wastecpu.c
+++ b/tool/build/wastecpu.c
@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/struct/sigaction.h"
 #include "libc/intrin/spinlock.h"
+#include "libc/intrin/wait0.internal.h"
 #include "libc/log/log.h"
 #include "libc/mem/mem.h"
 #include "libc/nexgen32e/threaded.h"
@@ -71,7 +72,7 @@ int main(int argc, char *argv[]) {
     usleep(1000);
   }
   for (i = 0; i < n; ++i) {
-    _spinlock((int *)(tls[i] + 0x38));
+    _wait0((int *)(tls[i] + 0x38));
     free(tls[i]);
   }
 }
diff --git a/tool/net/redbean.c b/tool/net/redbean.c
index 739afabb4..db0646c3d 100644
--- a/tool/net/redbean.c
+++ b/tool/net/redbean.c
@@ -36,6 +36,7 @@
 #include "libc/fmt/itoa.h"
 #include "libc/intrin/kprintf.h"
 #include "libc/intrin/nomultics.internal.h"
+#include "libc/intrin/wait0.internal.h"
 #include "libc/log/check.h"
 #include "libc/log/log.h"
 #include "libc/macros.internal.h"
@@ -6357,7 +6358,7 @@ static int ExitWorker(void) {
   }
   if (monitortty) {
     terminatemonitor = true;
-    _spinlock(monitortid);
+    _wait0(monitortid);
   }
   _Exit(0);
 }
@@ -7295,7 +7296,7 @@ void RedBean(int argc, char *argv[]) {
   if (!IsTiny()) {
     if (monitortty) {
       terminatemonitor = true;
-      _spinlock(monitortid);
+      _wait0(monitortid);
       munmap(monitorstack, GetStackSize());
       free(monitortls);
     }