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Write some lock contention tests

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This commit is contained in:
Justine Tunney 2022-06-16 09:06:09 -07:00
parent 42c38bc3e3
commit c06ffd458c
19 changed files with 205 additions and 76 deletions
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15
examples/greenbean.c
View file

@ -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);

2
libc/calls/getloadavg-nt.c
View file

@ -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) {

28
libc/intrin/once.h
View file

@ -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_ */

8
libc/intrin/pthread.h
View file

@ -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;

25
libc/intrin/pthread_mutex_lock.c
View file

@ -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;

2
libc/intrin/pthread_mutex_trylock.c
View file

@ -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;

6
libc/intrin/pthread_mutex_unlock.c
View file

@ -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;

38
libc/intrin/spinlock.h
View file

@ -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);

20
libc/intrin/wait0.internal.h Normal file
View file

@ -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_ */

2
libc/runtime/clone.c
View file

@ -63,7 +63,7 @@ struct CloneArgs {
int64_t tid64;
};
union {
int lock;
char lock;
void *pstack;
};
int *ctid;

2
libc/testlib/showerror.c
View file

@ -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,

1
libc/thread/join.c
View file

@ -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"

3
test/libc/calls/reservefd_test.c
View file

@ -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));

99
test/libc/intrin/pthread_mutex_lock_test.c
View file

@ -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());
}

6
test/libc/runtime/clone_test.c
View file

@ -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());
}

3
test/libc/stdio/dtoa_test.c
View file

@ -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));
}
}

13
tool/build/mkdeps.c
View file

@ -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));
}
}

3
tool/build/wastecpu.c
View file

@ -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]);
}
}

5
tool/net/redbean.c
View file

@ -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);
}