Messages in this thread | | | Date | Tue, 14 Dec 2004 13:50:19 -0800 | From | Roland McGrath <> | Subject | Re: [PATCH 1/7] cpu-timers: high-resolution CPU clocks for POSIX clock_* syscalls |
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I believe Christoph may have been referring exclusively to the per-process clocks, not the per-thread clocks. I'm not entirely sure since he used the term "process" exclusively, but quoted my paragraph about the per-thread clock access. Ulrich's reply is apropos to the individual thread clocks.
It was about the per-process clocks that I raised the question. For those, POSIX says it's implementation-defined what process can see the CPU clock of another process. That means we can make it as restricted or as free as we like, but we are obliged to document up front for the users what the semantics are. That's why I would like to make sure we have thought a little about the choices now, rather than someone coming along later and deciding we really ought to impose security on it (which might be be changing the story after developers reasonably coded to the implementation-defined behavior we documented in the first place).
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