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8043630: Method os::yield_all() should be removed

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Reviewed-by: dholmes, dsimms
This commit is contained in:
Frederic Parain 2014-06-23 06:58:26 -07:00
parent d9a2dbc73b
commit 5507f2b476
9 changed files with 9 additions and 58 deletions
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8
hotspot/src/share/vm/runtime/safepoint.cpp
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@ -264,8 +264,8 @@ void SafepointSynchronize::begin() {
//
// Further complicating matters is that yield() does not work as naively expected
// on many platforms -- yield() does not guarantee that any other ready threads
// will run. As such we revert yield_all() after some number of iterations.
// Yield_all() is implemented as a short unconditional sleep on some platforms.
// will run. As such we revert to naked_short_sleep() after some number of iterations.
// nakes_short_sleep() is implemented as a short unconditional sleep.
// Typical operating systems round a "short" sleep period up to 10 msecs, so sleeping
// can actually increase the time it takes the VM thread to detect that a system-wide
// stop-the-world safepoint has been reached. In a pathological scenario such as that
@ -322,9 +322,7 @@ void SafepointSynchronize::begin() {
if (steps < DeferThrSuspendLoopCount) {
os::NakedYield() ;
} else {
os::yield_all() ;
// Alternately, the VM thread could transiently depress its scheduling priority or
// transiently increase the priority of the tardy mutator(s).
os::naked_short_sleep(1);
}
iterations ++ ;