mirror of
https://github.com/torvalds/linux.git
synced 2024-11-23 20:51:44 +00:00
0fb298cf95
Block a bunch of threads on a futex and requeue them on another, N at a time. This program is particularly useful to measure the latency of nthread requeues without waking up any tasks -- thus mimicking a regular futex_wait. An example run: $ perf bench futex requeue -r 100 -t 64 Run summary [PID 151011]: Requeuing 64 threads (from 0x7d15c4 to 0x7d15c8), 1 at a time. [Run 1]: Requeued 64 of 64 threads in 0.0400 ms [Run 2]: Requeued 64 of 64 threads in 0.0390 ms [Run 3]: Requeued 64 of 64 threads in 0.0400 ms ... [Run 100]: Requeued 64 of 64 threads in 0.0390 ms Requeued 64 of 64 threads in 0.0399 ms (+-0.37%) Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Acked-by: Darren Hart <dvhart@linux.intel.com> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: Darren Hart <dvhart@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Low <jason.low2@hp.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Scott J Norton <scott.norton@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <Waiman.Long@hp.com> Link: http://lkml.kernel.org/r/1387081917-9102-4-git-send-email-davidlohr@hp.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
72 lines
2.2 KiB
C
72 lines
2.2 KiB
C
/*
|
|
* Glibc independent futex library for testing kernel functionality.
|
|
* Shamelessly stolen from Darren Hart <dvhltc@us.ibm.com>
|
|
* http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/
|
|
*/
|
|
|
|
#ifndef _FUTEX_H
|
|
#define _FUTEX_H
|
|
|
|
#include <unistd.h>
|
|
#include <sys/syscall.h>
|
|
#include <sys/types.h>
|
|
#include <linux/futex.h>
|
|
|
|
/**
|
|
* futex() - SYS_futex syscall wrapper
|
|
* @uaddr: address of first futex
|
|
* @op: futex op code
|
|
* @val: typically expected value of uaddr, but varies by op
|
|
* @timeout: typically an absolute struct timespec (except where noted
|
|
* otherwise). Overloaded by some ops
|
|
* @uaddr2: address of second futex for some ops\
|
|
* @val3: varies by op
|
|
* @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG
|
|
*
|
|
* futex() is used by all the following futex op wrappers. It can also be
|
|
* used for misuse and abuse testing. Generally, the specific op wrappers
|
|
* should be used instead. It is a macro instead of an static inline function as
|
|
* some of the types over overloaded (timeout is used for nr_requeue for
|
|
* example).
|
|
*
|
|
* These argument descriptions are the defaults for all
|
|
* like-named arguments in the following wrappers except where noted below.
|
|
*/
|
|
#define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \
|
|
syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3)
|
|
|
|
/**
|
|
* futex_wait() - block on uaddr with optional timeout
|
|
* @timeout: relative timeout
|
|
*/
|
|
static inline int
|
|
futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags)
|
|
{
|
|
return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags);
|
|
}
|
|
|
|
/**
|
|
* futex_wake() - wake one or more tasks blocked on uaddr
|
|
* @nr_wake: wake up to this many tasks
|
|
*/
|
|
static inline int
|
|
futex_wake(u_int32_t *uaddr, int nr_wake, int opflags)
|
|
{
|
|
return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags);
|
|
}
|
|
|
|
/**
|
|
* futex_cmp_requeue() - requeue tasks from uaddr to uaddr2
|
|
* @nr_wake: wake up to this many tasks
|
|
* @nr_requeue: requeue up to this many tasks
|
|
*/
|
|
static inline int
|
|
futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake,
|
|
int nr_requeue, int opflags)
|
|
{
|
|
return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2,
|
|
val, opflags);
|
|
}
|
|
|
|
#endif /* _FUTEX_H */
|