Messages in this thread | | | Date | Wed, 5 May 1999 08:37:33 +1000 | From | Richard Gooch <> | Subject | Re: Mark Russinovich's reponse Was: [OT] Comments to WinNT Mag !! (fwd) |
| |
Mark H. Wood writes: > On Sun, 2 May 1999, Ingo Molnar wrote: > > On Sun, 2 May 1999, Mark Russinovich wrote: > > > Completion ports in NT require no polling and no linear searching - that, > > > and their integration with the scheduler, is their entire reason for > > > existence. [...] > > > > they require a thread to block on completion ports, or to poll the status > > of the completion port. NT gives no way to asynchronously send completion > > events to a _running_ thread. > > Ugh. I liked the VMS model here. When you queue an I/O request, > one of the things you can attach to it is the address of a > procedure. When the request completes, the kernel creates a > temporary thread to execute the I/O rundown code, and part of that > rundown is to call the procedure you supplied. Your procedure would > typically move something from a wait queue to a work queue, or flip > a bit in a bitmask, or link a buffer onto the free chain, or > whatever it takes to indicate that your regular thread(s) should do > whatever you want done when the I/O has completed. When you return, > the rundown thread tidies up and destroys itself. (Of course, if > you never return, or you try to do huge amounts of processing in > your rundown procedure, your program won't work very well. Don't do > that. Keep it short and simple.)
What was the cost of creating the "temporary thread"? Anyway, we can do much the same thing with signals, except we don't need to create a temporary thread.
Regards,
Richard....
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |