What Do High-Level Memory Models Mean for Transactions?

What Do High-Level Memory Models Mean for Transactions?

Abstract
Many people have proposed adding transactions, or atomic blocks, to type-safe high-level programming languages. However, researchers have not considered the semantics of transactions with respect to a memory model weaker than sequential consistency. The details of such semantics are more subtle than many people realize, and the interaction between compiler transformations and transactions could produce behaviors that many people find surprising. A language’s memory model, which determines these interactions, must clearly indicate which behaviors are legal, and which are not. These design decisions affect both the idioms that are useful for designing concurrent software and the compiler transformations that are legal within the language.
Cases where semantics are more subtle than people expect include the actual meaning of both strong and weak atomicity; correct idioms for thread safe lazy initialization; compiler transformations of transactions that touch only thread local memory; and whether there is a well-defined notion for transactions that corresponds to the notion of correct and incorrect use of synchronization in Java. Open questions for a high-level memory-model that includes transactions involve both issues of isolation and ordering.

Oracle will support Sun's hardware platform

    Был пост посвященный процессору от SUNа - Rock. Oracle заявила:
    "... на новейшие аппаратные разработки этой компании Oracle имеет «большие планы». Эллисон признает, что одним из мотивов, побудивших его корпорацию купить Sun, являются именно аппаратные разработки. ..."
    "... Определенно, что мы будем развивать существующий аппаратный бизнес, это самое главное, на чем мы намерены сейчас сосредоточиться. Этот подход не противоречит стратегии Oracle ...".

    А вся соль в том, что новейшие разработки SUNа - это в том числе Hardware Transaction Memory (HTM).