--- a/hotspot/src/os/solaris/vm/os_solaris.cpp Wed Apr 02 16:08:59 2014 +0100
+++ b/hotspot/src/os/solaris/vm/os_solaris.cpp Thu Apr 03 09:28:28 2014 +0000
@@ -969,9 +969,6 @@
return true;
}
-// _T2_libthread is true if we believe we are running with the newer
-// SunSoft lwp/libthread.so (2.8 patch, 2.9 default)
-bool os::Solaris::_T2_libthread = false;
bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
// Allocate the OSThread object
@@ -1056,71 +1053,10 @@
thread->set_osthread(osthread);
// Create the Solaris thread
- // explicit THR_BOUND for T2_libthread case in case
- // that assumption is not accurate, but our alternate signal stack
- // handling is based on it which must have bound threads
thread_t tid = 0;
- long flags = (UseDetachedThreads ? THR_DETACHED : 0) | THR_SUSPENDED
- | ((UseBoundThreads || os::Solaris::T2_libthread() ||
- (thr_type == vm_thread) ||
- (thr_type == cgc_thread) ||
- (thr_type == pgc_thread) ||
- (thr_type == compiler_thread && BackgroundCompilation)) ?
- THR_BOUND : 0);
+ long flags = (UseDetachedThreads ? THR_DETACHED : 0) | THR_SUSPENDED;
int status;
- // 4376845 -- libthread/kernel don't provide enough LWPs to utilize all CPUs.
- //
- // On multiprocessors systems, libthread sometimes under-provisions our
- // process with LWPs. On a 30-way systems, for instance, we could have
- // 50 user-level threads in ready state and only 2 or 3 LWPs assigned
- // to our process. This can result in under utilization of PEs.
- // I suspect the problem is related to libthread's LWP
- // pool management and to the kernel's SIGBLOCKING "last LWP parked"
- // upcall policy.
- //
- // The following code is palliative -- it attempts to ensure that our
- // process has sufficient LWPs to take advantage of multiple PEs.
- // Proper long-term cures include using user-level threads bound to LWPs
- // (THR_BOUND) or using LWP-based synchronization. Note that there is a
- // slight timing window with respect to sampling _os_thread_count, but
- // the race is benign. Also, we should periodically recompute
- // _processors_online as the min of SC_NPROCESSORS_ONLN and the
- // the number of PEs in our partition. You might be tempted to use
- // THR_NEW_LWP here, but I'd recommend against it as that could
- // result in undesirable growth of the libthread's LWP pool.
- // The fix below isn't sufficient; for instance, it doesn't take into count
- // LWPs parked on IO. It does, however, help certain CPU-bound benchmarks.
- //
- // Some pathologies this scheme doesn't handle:
- // * Threads can block, releasing the LWPs. The LWPs can age out.
- // When a large number of threads become ready again there aren't
- // enough LWPs available to service them. This can occur when the
- // number of ready threads oscillates.
- // * LWPs/Threads park on IO, thus taking the LWP out of circulation.
- //
- // Finally, we should call thr_setconcurrency() periodically to refresh
- // the LWP pool and thwart the LWP age-out mechanism.
- // The "+3" term provides a little slop -- we want to slightly overprovision.
-
- if (AdjustConcurrency && os::Solaris::_os_thread_count < (_processors_online+3)) {
- if (!(flags & THR_BOUND)) {
- thr_setconcurrency (os::Solaris::_os_thread_count); // avoid starvation
- }
- }
- // Although this doesn't hurt, we should warn of undefined behavior
- // when using unbound T1 threads with schedctl(). This should never
- // happen, as the compiler and VM threads are always created bound
- DEBUG_ONLY(
- if ((VMThreadHintNoPreempt || CompilerThreadHintNoPreempt) &&
- (!os::Solaris::T2_libthread() && (!(flags & THR_BOUND))) &&
- ((thr_type == vm_thread) || (thr_type == cgc_thread) ||
- (thr_type == pgc_thread) || (thr_type == compiler_thread && BackgroundCompilation))) {
- warning("schedctl behavior undefined when Compiler/VM/GC Threads are Unbound");
- }
- );
-
-
// Mark that we don't have an lwp or thread id yet.
// In case we attempt to set the priority before the thread starts.
osthread->set_lwp_id(-1);
@@ -1145,13 +1081,6 @@
// Remember that we created this thread so we can set priority on it
osthread->set_vm_created();
- // Set the default thread priority. If using bound threads, setting
- // lwp priority will be delayed until thread start.
- set_native_priority(thread,
- DefaultThreadPriority == -1 ?
- java_to_os_priority[NormPriority] :
- DefaultThreadPriority);
-
// Initial thread state is INITIALIZED, not SUSPENDED
osthread->set_state(INITIALIZED);
@@ -1333,39 +1262,8 @@
jt->set_stack_size(stack_size);
}
- // 5/22/01: Right now alternate signal stacks do not handle
- // throwing stack overflow exceptions, see bug 4463178
- // Until a fix is found for this, T2 will NOT imply alternate signal
- // stacks.
- // If using T2 libthread threads, install an alternate signal stack.
- // Because alternate stacks associate with LWPs on Solaris,
- // see sigaltstack(2), if using UNBOUND threads, or if UseBoundThreads
- // we prefer to explicitly stack bang.
- // If not using T2 libthread, but using UseBoundThreads any threads
- // (primordial thread, jni_attachCurrentThread) we do not create,
- // probably are not bound, therefore they can not have an alternate
- // signal stack. Since our stack banging code is generated and
- // is shared across threads, all threads must be bound to allow
- // using alternate signal stacks. The alternative is to interpose
- // on _lwp_create to associate an alt sig stack with each LWP,
- // and this could be a problem when the JVM is embedded.
- // We would prefer to use alternate signal stacks with T2
- // Since there is currently no accurate way to detect T2
- // we do not. Assuming T2 when running T1 causes sig 11s or assertions
- // on installing alternate signal stacks
-
-
- // 05/09/03: removed alternate signal stack support for Solaris
- // The alternate signal stack mechanism is no longer needed to
- // handle stack overflow. This is now handled by allocating
- // guard pages (red zone) and stackbanging.
- // Initially the alternate signal stack mechanism was removed because
- // it did not work with T1 llibthread. Alternate
- // signal stacks MUST have all threads bound to lwps. Applications
- // can create their own threads and attach them without their being
- // bound under T1. This is frequently the case for the primordial thread.
- // If we were ever to reenable this mechanism we would need to
- // use the dynamic check for T2 libthread.
+ // With the T2 libthread (T1 is no longer supported) threads are always bound
+ // and we use stackbanging in all cases.
os::Solaris::init_thread_fpu_state();
std::set_terminate(_handle_uncaught_cxx_exception);
@@ -2092,12 +1990,7 @@
}
void os::Solaris::print_libversion_info(outputStream* st) {
- if (os::Solaris::T2_libthread()) {
- st->print(" (T2 libthread)");
- }
- else {
- st->print(" (T1 libthread)");
- }
+ st->print(" (T2 libthread)");
st->cr();
}
@@ -3323,41 +3216,10 @@
os::YieldResult os::NakedYield() { thr_yield(); return os::YIELD_UNKNOWN; }
-
-// On Solaris we found that yield_all doesn't always yield to all other threads.
-// There have been cases where there is a thread ready to execute but it doesn't
-// get an lwp as the VM thread continues to spin with sleeps of 1 millisecond.
-// The 1 millisecond wait doesn't seem long enough for the kernel to issue a
-// SIGWAITING signal which will cause a new lwp to be created. So we count the
-// number of times yield_all is called in the one loop and increase the sleep
-// time after 8 attempts. If this fails too we increase the concurrency level
-// so that the starving thread would get an lwp
-
-void os::yield_all(int attempts) {
+void os::yield_all() {
// Yields to all threads, including threads with lower priorities
- if (attempts == 0) {
- os::sleep(Thread::current(), 1, false);
- } else {
- int iterations = attempts % 30;
- if (iterations == 0 && !os::Solaris::T2_libthread()) {
- // thr_setconcurrency and _getconcurrency make sense only under T1.
- int noofLWPS = thr_getconcurrency();
- if (noofLWPS < (Threads::number_of_threads() + 2)) {
- thr_setconcurrency(thr_getconcurrency() + 1);
- }
- } else if (iterations < 25) {
- os::sleep(Thread::current(), 1, false);
- } else {
- os::sleep(Thread::current(), 10, false);
- }
- }
-}
-
-// Called from the tight loops to possibly influence time-sharing heuristics
-void os::loop_breaker(int attempts) {
- os::yield_all(attempts);
-}
-
+ os::sleep(Thread::current(), 1, false);
+}
// Interface for setting lwp priorities. If we are using T2 libthread,
// which forces the use of BoundThreads or we manually set UseBoundThreads,
@@ -3365,6 +3227,9 @@
// function is meaningless in this mode so we must adjust the real lwp's priority
// The routines below implement the getting and setting of lwp priorities.
//
+// Note: T2 is now the only supported libthread. UseBoundThreads flag is
+// being deprecated and all threads are now BoundThreads
+//
// Note: There are three priority scales used on Solaris. Java priotities
// which range from 1 to 10, libthread "thr_setprio" scale which range
// from 0 to 127, and the current scheduling class of the process we
@@ -3437,29 +3302,19 @@
if (!UseThreadPriorities) return 0;
- // We are using Bound threads, we need to determine our priority ranges
- if (os::Solaris::T2_libthread() || UseBoundThreads) {
- // If ThreadPriorityPolicy is 1, switch tables
- if (ThreadPriorityPolicy == 1) {
- for (i = 0 ; i < CriticalPriority+1; i++)
- os::java_to_os_priority[i] = prio_policy1[i];
- }
- if (UseCriticalJavaThreadPriority) {
- // MaxPriority always maps to the FX scheduling class and criticalPrio.
- // See set_native_priority() and set_lwp_class_and_priority().
- // Save original MaxPriority mapping in case attempt to
- // use critical priority fails.
- java_MaxPriority_to_os_priority = os::java_to_os_priority[MaxPriority];
- // Set negative to distinguish from other priorities
- os::java_to_os_priority[MaxPriority] = -criticalPrio;
- }
- }
- // Not using Bound Threads, set to ThreadPolicy 1
- else {
- for ( i = 0 ; i < CriticalPriority+1; i++ ) {
+ // If ThreadPriorityPolicy is 1, switch tables
+ if (ThreadPriorityPolicy == 1) {
+ for (i = 0 ; i < CriticalPriority+1; i++)
os::java_to_os_priority[i] = prio_policy1[i];
- }
- return 0;
+ }
+ if (UseCriticalJavaThreadPriority) {
+ // MaxPriority always maps to the FX scheduling class and criticalPrio.
+ // See set_native_priority() and set_lwp_class_and_priority().
+ // Save original MaxPriority mapping in case attempt to
+ // use critical priority fails.
+ java_MaxPriority_to_os_priority = os::java_to_os_priority[MaxPriority];
+ // Set negative to distinguish from other priorities
+ os::java_to_os_priority[MaxPriority] = -criticalPrio;
}
// Get IDs for a set of well-known scheduling classes.
@@ -3583,10 +3438,6 @@
// set_lwp_class_and_priority
-//
-// Set the class and priority of the lwp. This call should only
-// be made when using bound threads (T2 threads are bound by default).
-//
int set_lwp_class_and_priority(int ThreadID, int lwpid,
int newPrio, int new_class, bool scale) {
int rslt;
@@ -3812,23 +3663,20 @@
status = thr_setprio(thread->osthread()->thread_id(), newpri);
}
- if (os::Solaris::T2_libthread() ||
- (UseBoundThreads && osthread->is_vm_created())) {
- int lwp_status =
- set_lwp_class_and_priority(osthread->thread_id(),
- osthread->lwp_id(),
- newpri,
- fxcritical ? fxLimits.schedPolicy : myClass,
- !fxcritical);
- if (lwp_status != 0 && fxcritical) {
- // Try again, this time without changing the scheduling class
- newpri = java_MaxPriority_to_os_priority;
- lwp_status = set_lwp_class_and_priority(osthread->thread_id(),
- osthread->lwp_id(),
- newpri, myClass, false);
- }
- status |= lwp_status;
- }
+ int lwp_status =
+ set_lwp_class_and_priority(osthread->thread_id(),
+ osthread->lwp_id(),
+ newpri,
+ fxcritical ? fxLimits.schedPolicy : myClass,
+ !fxcritical);
+ if (lwp_status != 0 && fxcritical) {
+ // Try again, this time without changing the scheduling class
+ newpri = java_MaxPriority_to_os_priority;
+ lwp_status = set_lwp_class_and_priority(osthread->thread_id(),
+ osthread->lwp_id(),
+ newpri, myClass, false);
+ }
+ status |= lwp_status;
return (status == 0) ? OS_OK : OS_ERR;
}
@@ -4495,13 +4343,6 @@
}
}
-// (Static) wrappers for the new libthread API
-int_fnP_thread_t_iP_uP_stack_tP_gregset_t os::Solaris::_thr_getstate;
-int_fnP_thread_t_i_gregset_t os::Solaris::_thr_setstate;
-int_fnP_thread_t_i os::Solaris::_thr_setmutator;
-int_fnP_thread_t os::Solaris::_thr_suspend_mutator;
-int_fnP_thread_t os::Solaris::_thr_continue_mutator;
-
// (Static) wrapper for getisax(2) call.
os::Solaris::getisax_func_t os::Solaris::_getisax = 0;
@@ -4536,78 +4377,9 @@
return addr;
}
-
-
-// isT2_libthread()
-//
-// Routine to determine if we are currently using the new T2 libthread.
-//
-// We determine if we are using T2 by reading /proc/self/lstatus and
-// looking for a thread with the ASLWP bit set. If we find this status
-// bit set, we must assume that we are NOT using T2. The T2 team
-// has approved this algorithm.
-//
-// We need to determine if we are running with the new T2 libthread
-// since setting native thread priorities is handled differently
-// when using this library. All threads created using T2 are bound
-// threads. Calling thr_setprio is meaningless in this case.
-//
-bool isT2_libthread() {
- static prheader_t * lwpArray = NULL;
- static int lwpSize = 0;
- static int lwpFile = -1;
- lwpstatus_t * that;
- char lwpName [128];
- bool isT2 = false;
-
-#define ADR(x) ((uintptr_t)(x))
-#define LWPINDEX(ary,ix) ((lwpstatus_t *)(((ary)->pr_entsize * (ix)) + (ADR((ary) + 1))))
-
- lwpFile = ::open("/proc/self/lstatus", O_RDONLY, 0);
- if (lwpFile < 0) {
- if (ThreadPriorityVerbose) warning ("Couldn't open /proc/self/lstatus\n");
- return false;
- }
- lwpSize = 16*1024;
- for (;;) {
- ::lseek64 (lwpFile, 0, SEEK_SET);
- lwpArray = (prheader_t *)NEW_C_HEAP_ARRAY(char, lwpSize, mtInternal);
- if (::read(lwpFile, lwpArray, lwpSize) < 0) {
- if (ThreadPriorityVerbose) warning("Error reading /proc/self/lstatus\n");
- break;
- }
- if ((lwpArray->pr_nent * lwpArray->pr_entsize) <= lwpSize) {
- // We got a good snapshot - now iterate over the list.
- int aslwpcount = 0;
- for (int i = 0; i < lwpArray->pr_nent; i++ ) {
- that = LWPINDEX(lwpArray,i);
- if (that->pr_flags & PR_ASLWP) {
- aslwpcount++;
- }
- }
- if (aslwpcount == 0) isT2 = true;
- break;
- }
- lwpSize = lwpArray->pr_nent * lwpArray->pr_entsize;
- FREE_C_HEAP_ARRAY(char, lwpArray, mtInternal); // retry.
- }
-
- FREE_C_HEAP_ARRAY(char, lwpArray, mtInternal);
- ::close (lwpFile);
- if (ThreadPriorityVerbose) {
- if (isT2) tty->print_cr("We are running with a T2 libthread\n");
- else tty->print_cr("We are not running with a T2 libthread\n");
- }
- return isT2;
-}
-
-
void os::Solaris::libthread_init() {
address func = (address)dlsym(RTLD_DEFAULT, "_thr_suspend_allmutators");
- // Determine if we are running with the new T2 libthread
- os::Solaris::set_T2_libthread(isT2_libthread());
-
lwp_priocntl_init();
// RTLD_DEFAULT was not defined on some early versions of 5.5.1
@@ -4618,22 +4390,6 @@
guarantee(func != NULL, "libthread.so is too old.");
}
- // Initialize the new libthread getstate API wrappers
- func = resolve_symbol("thr_getstate");
- os::Solaris::set_thr_getstate(CAST_TO_FN_PTR(int_fnP_thread_t_iP_uP_stack_tP_gregset_t, func));
-
- func = resolve_symbol("thr_setstate");
- os::Solaris::set_thr_setstate(CAST_TO_FN_PTR(int_fnP_thread_t_i_gregset_t, func));
-
- func = resolve_symbol("thr_setmutator");
- os::Solaris::set_thr_setmutator(CAST_TO_FN_PTR(int_fnP_thread_t_i, func));
-
- func = resolve_symbol("thr_suspend_mutator");
- os::Solaris::set_thr_suspend_mutator(CAST_TO_FN_PTR(int_fnP_thread_t, func));
-
- func = resolve_symbol("thr_continue_mutator");
- os::Solaris::set_thr_continue_mutator(CAST_TO_FN_PTR(int_fnP_thread_t, func));
-
int size;
void (*handler_info_func)(address *, int *);
handler_info_func = CAST_TO_FN_PTR(void (*)(address *, int *), resolve_symbol("thr_sighndlrinfo"));
@@ -5536,11 +5292,7 @@
}
bool os::is_thread_cpu_time_supported() {
- if ( os::Solaris::T2_libthread() || UseBoundThreads ) {
- return true;
- } else {
- return false;
- }
+ return true;
}
// System loadavg support. Returns -1 if load average cannot be obtained.