Keean Schupke wrote:
Okay, my ignorance of Posix is showing again. Is it currently the case, then, that every GHC thread will stop running while a disk read is in progress in any thread? Is this true on all platforms?
It's true on Unix-like systems, I believe. Even with -threaded. It might not be true on Win32.
I think this is not true on linux, where a thread is just a process created with special flags to keep the same fds and memory.
As threads on linux are scheduled like processes, one thread blocking should not affect the others?
That should be true of all POSIX-like thread implementations
(including Linux, whose threads aren't quite POSIX-compliant, e.g. in
regard to signal handling, but aren't that far off).
Essentially, blocking system calls only block the calling kernel
thread.
OTOH, if you are implementing multiple user-space threads within a
single kernel thread, if that kernel thread blocks, all of the
user-space threads within it will be blocked.
--
Glynn Clements