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Cliff Jansen commented on PROTON-640: ------------------------------------- from https://reviews.apache.org/r/24159 This patch follows the QPID AsynchIO.cpp version fairly closely with the following main differences: - addition of async connect - multiple outstanding concurrent writes (a write pipeline) - non-buffered reads - graceful close progressing to hard close (much as proposed in QPID-5668) Careful scrutiny of the selector API change is warranted (constructor). Thread safety is currently assured only by isolating a paired pn_selector_t and pn_io_t from other such pairs. If anticipated use cases suggest either that multiple selectors be used with an io, or with multiple io's, or that a socket should be movable between selectors during it's lifetime, then additional locking semantics will be required. These scenarios come for free in Linux where the OS barrier takes care of concurrency issues. By contrast, the Windows code implements the selector in user space. This API change just forces the pairing of the selector with the io. The user is still expected to free the selector when done. Perhaps this should be handled by the io when it closes, or some alternative API mechanism should be used. In any event, if the supported use cases preclude closely linking one selector with one io, then this is moot. Performance notes. The use of a write pipeline has a significant effect on sending performance, especially with a small number of connections. It would probably be a useful enhancement for the QPID code. On the read side, no async read buffer is used (relying instead on the OS input buffering system). This is because pn_recv() copies out the bytes anyway (rather than passing a buffer as in QPID). > IO completion port Windows IO for Proton > ---------------------------------------- > > Key: PROTON-640 > URL: https://issues.apache.org/jira/browse/PROTON-640 > Project: Qpid Proton > Issue Type: Improvement > Components: proton-c > Affects Versions: 0.7 > Environment: Windows > Reporter: Cliff Jansen > Assignee: Cliff Jansen > Fix For: 0.8 > > > Provide a native IO completion port layer similar to the C++ QPID version for > Proton. -- This message was sent by Atlassian JIRA (v6.3.4#6332)