8187042: Events to show which objects are associated with biased object revocations
Reviewed-by: mgronlun, dholmes, egahlin
Contributed-by: robin.westberg@oracle.com
--- a/src/hotspot/share/runtime/biasedLocking.cpp Mon Oct 16 16:44:23 2017 +0200
+++ b/src/hotspot/share/runtime/biasedLocking.cpp Mon Oct 16 18:25:07 2017 +0200
@@ -35,6 +35,7 @@
#include "runtime/vframe.hpp"
#include "runtime/vmThread.hpp"
#include "runtime/vm_operations.hpp"
+#include "trace/tracing.hpp"
static bool _biased_locking_enabled = false;
BiasedLockingCounters BiasedLocking::_counters;
@@ -643,23 +644,43 @@
// stale epoch.
ResourceMark rm;
log_info(biasedlocking)("Revoking bias by walking my own stack:");
+ EventBiasedLockSelfRevocation event;
BiasedLocking::Condition cond = revoke_bias(obj(), false, false, (JavaThread*) THREAD);
((JavaThread*) THREAD)->set_cached_monitor_info(NULL);
assert(cond == BIAS_REVOKED, "why not?");
+ if (event.should_commit()) {
+ event.set_lockClass(k);
+ event.commit();
+ }
return cond;
} else {
+ EventBiasedLockRevocation event;
VM_RevokeBias revoke(&obj, (JavaThread*) THREAD);
VMThread::execute(&revoke);
+ if (event.should_commit() && (revoke.status_code() != NOT_BIASED)) {
+ event.set_lockClass(k);
+ // Subtract 1 to match the id of events committed inside the safepoint
+ event.set_safepointId(SafepointSynchronize::safepoint_counter() - 1);
+ event.commit();
+ }
return revoke.status_code();
}
}
assert((heuristics == HR_BULK_REVOKE) ||
(heuristics == HR_BULK_REBIAS), "?");
+ EventBiasedLockClassRevocation event;
VM_BulkRevokeBias bulk_revoke(&obj, (JavaThread*) THREAD,
(heuristics == HR_BULK_REBIAS),
attempt_rebias);
VMThread::execute(&bulk_revoke);
+ if (event.should_commit()) {
+ event.set_revokedClass(obj->klass());
+ event.set_disableBiasing((heuristics != HR_BULK_REBIAS));
+ // Subtract 1 to match the id of events committed inside the safepoint
+ event.set_safepointId(SafepointSynchronize::safepoint_counter() - 1);
+ event.commit();
+ }
return bulk_revoke.status_code();
}
--- a/src/hotspot/share/trace/traceevents.xml Mon Oct 16 16:44:23 2017 +0200
+++ b/src/hotspot/share/trace/traceevents.xml Mon Oct 16 18:25:07 2017 +0200
@@ -104,6 +104,24 @@
<value type="INFLATECAUSE" field="cause" label="Monitor Inflation Cause" description="Cause of inflation"/>
</event>
+ <event id="BiasedLockRevocation" path="java/biased_lock_revocation" label="Biased Lock Revocation"
+ description="Revoked bias of object" has_thread="true" has_stacktrace="true" is_instant="false">
+ <value type="CLASS" field="lockClass" label="Lock Class" description="Class of object whose biased lock was revoked"/>
+ <value type="INTEGER" field="safepointId" label="Safepoint Identifier" relation="SafepointId"/>
+ </event>
+
+ <event id="BiasedLockSelfRevocation" path="java/biased_lock_self_revocation" label="Biased Lock Self Revocation"
+ description="Revoked bias of object biased towards own thread" has_thread="true" has_stacktrace="true" is_instant="false">
+ <value type="CLASS" field="lockClass" label="Lock Class" description="Class of object whose biased lock was revoked"/>
+ </event>
+
+ <event id="BiasedLockClassRevocation" path="java/biased_lock_class_revocation" label="Biased Lock Class Revocation"
+ description="Revoked biases for all instances of a class" has_thread="true" has_stacktrace="true" is_instant="false">
+ <value type="CLASS" field="revokedClass" label="Revoked Class" description="Class whose biased locks were revoked"/>
+ <value type="BOOLEAN" field="disableBiasing" label="Disable Further Biasing" description="Whether further biasing for instances of this class will be allowed"/>
+ <value type="INTEGER" field="safepointId" label="Safepoint Identifier" relation="SafepointId"/>
+ </event>
+
<event id="ReservedStackActivation" path="vm/runtime/reserved_stack_activation" label="Reserved Stack Activation"
description="Activation of Reserved Stack Area caused by stack overflow with ReservedStackAccess annotated method in call stack"
has_thread="true" has_stacktrace="true" is_instant="true">