perf/bench/futex.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 /*
0003  * Glibc independent futex library for testing kernel functionality.
0004  * Shamelessly stolen from Darren Hart <dvhltc@us.ibm.com>
0005  *    http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/
0006  */
0007
0008 #ifndef _FUTEX_H
0009 #define _FUTEX_H
0010
0011 #include <unistd.h>
0012 #include <sys/syscall.h>
0013 #include <sys/types.h>
0014 #include <linux/futex.h>
0015
0016 struct bench_futex_parameters {
0017     bool silent;
0018     bool fshared;
0019     bool mlockall;
0020     bool multi; /* lock-pi */
0021     bool pi; /* requeue-pi */
0022     bool broadcast; /* requeue */
0023     unsigned int runtime; /* seconds*/
0024     unsigned int nthreads;
0025     unsigned int nfutexes;
0026     unsigned int nwakes;
0027     unsigned int nrequeue;
0028 };
0029
0030 /**
0031  * futex_syscall() - SYS_futex syscall wrapper
0032  * @uaddr:  address of first futex
0033  * @op:     futex op code
0034  * @val:    typically expected value of uaddr, but varies by op
0035  * @timeout:    typically an absolute struct timespec (except where noted
0036  *      otherwise). Overloaded by some ops
0037  * @uaddr2: address of second futex for some ops
0038  * @val3:   varies by op
0039  * @opflags:    flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG
0040  *
0041  * futex_syscall() is used by all the following futex op wrappers. It can also be
0042  * used for misuse and abuse testing. Generally, the specific op wrappers
0043  * should be used instead.
0044  *
0045  * These argument descriptions are the defaults for all
0046  * like-named arguments in the following wrappers except where noted below.
0047  */
0048 static inline int
0049 futex_syscall(volatile u_int32_t *uaddr, int op, u_int32_t val, struct timespec *timeout,
0050           volatile u_int32_t *uaddr2, int val3, int opflags)
0051 {
0052     return syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3);
0053 }
0054
0055 static inline int
0056 futex_syscall_nr_requeue(volatile u_int32_t *uaddr, int op, u_int32_t val, int nr_requeue,
0057              volatile u_int32_t *uaddr2, int val3, int opflags)
0058 {
0059     return syscall(SYS_futex, uaddr, op | opflags, val, nr_requeue, uaddr2, val3);
0060 }
0061
0062 /**
0063  * futex_wait() - block on uaddr with optional timeout
0064  * @timeout:    relative timeout
0065  */
0066 static inline int
0067 futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags)
0068 {
0069     return futex_syscall(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags);
0070 }
0071
0072 /**
0073  * futex_wake() - wake one or more tasks blocked on uaddr
0074  * @nr_wake:    wake up to this many tasks
0075  */
0076 static inline int
0077 futex_wake(u_int32_t *uaddr, int nr_wake, int opflags)
0078 {
0079     return futex_syscall(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags);
0080 }
0081
0082 /**
0083  * futex_lock_pi() - block on uaddr as a PI mutex
0084  */
0085 static inline int
0086 futex_lock_pi(u_int32_t *uaddr, struct timespec *timeout, int opflags)
0087 {
0088     return futex_syscall(uaddr, FUTEX_LOCK_PI, 0, timeout, NULL, 0, opflags);
0089 }
0090
0091 /**
0092  * futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter
0093  */
0094 static inline int
0095 futex_unlock_pi(u_int32_t *uaddr, int opflags)
0096 {
0097     return futex_syscall(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags);
0098 }
0099
0100 /**
0101 * futex_cmp_requeue() - requeue tasks from uaddr to uaddr2
0102 * @nr_wake:        wake up to this many tasks
0103 * @nr_requeue:     requeue up to this many tasks
0104 */
0105 static inline int
0106 futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake,
0107          int nr_requeue, int opflags)
0108 {
0109     return futex_syscall_nr_requeue(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2,
0110                     val, opflags);
0111 }
0112
0113 /**
0114  * futex_wait_requeue_pi() - block on uaddr and prepare to requeue to uaddr2
0115  * @uaddr:  non-PI futex source
0116  * @uaddr2: PI futex target
0117  *
0118  * This is the first half of the requeue_pi mechanism. It shall always be
0119  * paired with futex_cmp_requeue_pi().
0120  */
0121 static inline int
0122 futex_wait_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2,
0123               struct timespec *timeout, int opflags)
0124 {
0125     return futex_syscall(uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0,
0126                  opflags);
0127 }
0128
0129 /**
0130  * futex_cmp_requeue_pi() - requeue tasks from uaddr to uaddr2
0131  * @uaddr:  non-PI futex source
0132  * @uaddr2: PI futex target
0133  * @nr_requeue: requeue up to this many tasks
0134  *
0135  * This is the second half of the requeue_pi mechanism. It shall always be
0136  * paired with futex_wait_requeue_pi(). The first waker is always awoken.
0137  */
0138 static inline int
0139 futex_cmp_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2,
0140              int nr_requeue, int opflags)
0141 {
0142     return futex_syscall_nr_requeue(uaddr, FUTEX_CMP_REQUEUE_PI, 1, nr_requeue, uaddr2,
0143                     val, opflags);
0144 }
0145
0146 #endif /* _FUTEX_H */