detach/join.
- Make mutex acquire spin for a short time, as done with spinlocks.
- Make the number of spins controllable with the env var PTHREAD_NSPINS.
- Reduce the amount of time that libpthread internal spinlocks are held.
- Rely more on the barrier effects of park/unpark to avoid taking spinlocks.
- Simplify the locking around pthreads and the global queues.
- Align per-thread sync data on a 128 byte boundary.
- Offset thread stacks by a small amount to try and reduce cache thrash.
After resuming execution, the thread must check to see if it
has been restarted as a result of pthread_cond_signal(). If it
has, but cannot take the wakeup (because of eg a pending Unix
signal or timeout) then try to ensure that another thread sees
it. This is necessary because there may be multiple waiters,
and at least one should take the wakeup if possible.
so avoid making them.
- When parking an LWP on a condition variable, point the hint argument at
the mutex's waiters queue. Chances are we will be awoken from that later.
be used only as as a hint. Clear the pointer when releasing the mutex.
- When releasing a mutex, wake all waiters. Makes it possible to tranfer
waiters from another object to a mutex.
any threads are created turned out to be not such a good idea.
there are stronger requirements on what has to work in a forked child
while a process is still single-threaded. so take all that stuff
back out and fix the problems with single-threaded programs that
are linked with libpthread differently, by checking if the library
has been started and doing completely different stuff if it hasn't been:
- for pthread_rwlock_timedrdlock(), just fail with EDEADLK immediately.
- for sem_wait(), the only thing that can unlock the semaphore is a
signal handler, so use sigsuspend() to wait for a signal.
- for pthread_mutex_lock_slow(), just go into an infinite loop
waiting for signals.
I also noticed that there's a "sem2" test that has never worked in its
single-threaded form. the problem there is that a signal handler tries
to take a sem_t interlock which is already held when the signal is received.
fix this too, by adding a single-threaded case for sig_trywait() that
blocks signals instead of using the userland interlock.
call pthread__start() if it hasn't already been called. this avoids
an internal assertion from the library if these routines are used
before any threads are created and they need to sleep.
fixes PR 20256, PR 24241, PR 25722, PR 26096.
- enable concurrency according to environment variable PTHREAD_CONCURRENCY
- add idle VP wakeup if there are additional jobs and idle VPs
- make reidlequeue per VP
- enable spinning for locks
- fix race condition in alarm processing
- fix race condition in mutex locking
- make debugging output line buffered and add VP prefix to debug lines
- add pt_stackinfo to struct __pthread_st
- add pthread__stackinfo_offset returning the offset from ss_sp to
pt_stackinfo
- pass stackinfo_offset to sa_register and set SA_FLAG_STACKINFO to
make the kernel use it
- call pthread__sa_recycle in pthread__resolve_locks; g/c recycleq and
pthread__recycle_bulk
- return stack in pthread__sa_recycle by incrementing sasi_stackgen
- make pthread__sa_recycle debugging output formatting conditional on
pthread__debug_newline
with the shell's command to change limits. Make the PTHREAD_STACKSIZE
environment variable override the default stack size. The old fixed
stack size behaviour can be enable with PT_FIXEDSTACKSIZE_LG when building
libpthread.
int pthread_attr_setcreatesuspend_np(pthread_attr_t *);
int pthread_suspend_np(pthread_t);
int pthread_resume_np(pthread_t);
needed for java. Approved and fixed by cl.
by the kernel. Separating this from pt_uc makes it possible to avoid a race
condition in pt_uc management near the STACK_SWITCH part of pthread__switch()
and pthread__locked_switch().
Remove pt_sleepuc pointer, which was made obsolete by the previous round of
UC juggling but still present in the assembler files.
1. add new pthread__abort() and change pthread_assert(0) to it.
2. put constcond in the right place (in the macro).
3. no space after pthread__assert macro.
opposed to internal errors. The setting of the PTHREAD_ERRORMODE
environment variable determines the runtime behavior. Valid settings
are "ignore", "abort", and "print". The default is currently "abort".
* pthread_attr_getname_np()
* pthread_attr_setname_np()
* pthread_getname_np()
* pthread_setname_np()
In addition to being query'able by the application (for log messages, etc.),
it is intended that these names can show up in the debugger.
Reviewed by nathanw.
over a sleep queue and puts everything on the run queue. This permits
the iteration to be inside the acquisition of the run queue spinlock,
avoiding repetitive acquire/release cycles.
- Signal handlers now simply continue executing the current thread,
rather than trying to put themselves back on the queue that they came
from, which was rather fragile. As a result, all callers of
pthread__block() must be prepared to handle spurious wakeups.
- When a signal arrives for a thread that is blocked in the kernel,
note this in another field in pthread_st and set a flag. Process the
signal and set up the trampoline for the handler *after* the thread
unblocks, so that both the trampoline and the returned state from
the kernel are preserved.
- Factor out some code into a pthread__deliver_signal() routine;
the signal-taking code in pthread_sigmask() should be able to use this
soon.
This is still gross, and there are still some terrible MP issues lurking here,
but progress crawls along.
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