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    SubjectRe: PROBLEM: pthread-safety bug in write(2) on Linux 2.6.x
    Dan Bonachea <bonachead@comcast.net> wrote:
    >
    > This problem arose in the parallel runtime system for a scientific language
    > compiler (nearly a million lines of code total - definitely a "real-world"
    > program) - the example code is merely a pared-down demonstration of the
    > problem. In parallel scientific computing, it's very common for many threads
    > to be writing to stdout (usually for monitoring purposes) and it's expected
    > and normal for output from separate threads to be arbitrarily interleaved, but
    > it's *not* ok for output to be lost entirely. This is essentially equivalent
    > to the real-world example you gave of many threads logging to a file.

    Interesting - afaik that's the first time this has been hit in a real
    application.

    > We've worked around the problem in Linux 2.6 by adding locking at user-level
    > around our writes, as you suggest, although this of course penalizes our
    > performance on kernels that already correctly implement the thread-safety
    > required by the POSIX spec. In any case it seemed like a problem that we
    > should report, to be good open-source citizens - especially given that it
    > appears to be a regression with respect to the Linux 2.4 kernel. How you
    > choose to handle the report is of course your decision.

    yup, thanks.
    -
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