US 9,430,275 B2Granted

Synchronization between concurrent notifier and waiter transactions using transaction condition variables

AssigneeOracle International Corporation

InventorsVirendra J. Marathe, Victor M. Luchangco

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Abstract

Transactional memory implementations may be extended to support transaction communicators and/or transaction condition variables for which transaction isolation is relaxed, and through which concurrent transactions can communicate and be synchronized with each other. Transactional accesses to these objects may not be isolated unless called within communicator-isolating transactions. A waiter transaction may invoke a wait method of a transaction condition variable, be added to a wait list for the variable, and be suspended pending notification of a notification event from a notify method of the variable. A notifier transaction may invoke a notify method of the variable, which may remove the waiter from the wait list, schedule the waiter transaction for resumed execution, and notify the waiter of the notification event. A waiter transaction may commit only if the corresponding notifier transaction commits. If the waiter transaction aborts, the notification may be forwarded to another waiter.

Claims20

Dependent claims

A method, comprising:

performing, by a computer:
executing a plurality of concurrent transactions, wherein the plurality of concurrent transactions comprises a waiter transaction and a notifier transaction;
the waiter transaction invoking a wait method of a transaction condition variable, wherein invoking the wait method creates a one-way dependency between the waiter transaction and the notifier transaction such that the waiter transaction cannot commit until the notifier transaction commits but the notifier transaction is not dependent on the waiter transaction, wherein the transaction condition variable is a condition variable for which transaction isolation has been relaxed so that the waiter transaction and the notifier transaction can communicate through the transaction condition variable;
suspending execution of the waiter transaction pending notification of a notification event from a notify method of the transaction condition variable;
the notifier transaction invoking the notify method of the transaction condition variable, wherein the notify method notifies the waiter transaction of a notification event;
and
in response to receiving the notification of the notification event, the waiter transaction:
resuming execution;
and
in response to determining that the notifier transaction has successfully committed, attempting to commit the waiter transaction.

7 more elements

A system comprising:

one or more processors;
and
memory coupled to the one or more processors and storing program instructions that when executed by the one or more processors cause the one or more processors to perform:
executing a plurality of concurrent transactions, wherein the plurality of concurrent transactions comprises a waiter transaction and a notifier transaction;
the waiter transaction invoking a wait method of a transaction condition variable, wherein invoking the wait method creates a one-way dependency between the waiter transaction and the notifier transaction such that the waiter transaction cannot commit until the notifier transaction commits but the notifier transaction is not dependent on the waiter transaction, wherein the transaction condition variable is a condition variable for which transaction isolation has been relaxed so that the waiter transaction and the notifier transaction can communicate through the transaction condition variable;
suspending execution of the waiter transaction pending notification of a notification event from a notify method of the transaction condition variable;
the notifier transaction invoking the notify method of the transaction condition variable, wherein the notify method notifies the waiter transaction of a notification event;
and
in response to receiving the notification of the notification event, the waiter transaction:
resuming execution;
and
in response to determining that the notifier transaction has successfully committed, attempting to commit the waiter transaction.

9 more elements

A non-transitory, computer readable storage medium storing program instructions that when executed by one or more computers cause the one or more computers to perform:

executing a plurality of concurrent transactions, wherein the plurality of concurrent transactions comprises a waiter transaction and a notifier transaction;
the waiter transaction invoking a wait method of a transaction condition variable, wherein invoking the wait method creates a one-way dependency between the waiter transaction and the notifier transaction such that the waiter transaction cannot commit until the notifier transaction commits but the notifier transaction is not dependent on the waiter transaction, wherein the transaction condition variable is a condition variable for which transaction isolation has been relaxed so that the waiter transaction and the notifier transaction can communicate through the transaction condition variable;
suspending execution of the waiter transaction pending notification of a notification event from a notify method of the transaction condition variable;
the notifier transaction invoking the notify method of the transaction condition variable, wherein the notify method notifies the waiter transaction of a notification event;
and
in response to receiving the notification of the notification event, the waiter transaction:
resuming execution;
and
in response to determining that the notifier transaction has successfully committed, attempting to commit the waiter transaction.

6 more elements

Dependencies are inferred from the claim text.