Re: Fast user Space Mutexes (aka Futexes)

[Hiten Pandya <hmp@xxxxxxxxxxxxx>]

Matthew Dillon wrote:

>     Remember everyone that we are talking about two layers in userland
>     here... the core layer is intended to be the LWKT port and will
>     include a messaging implementation for all system calls.  Then a POSIX
>     layer will be placed on top of that.
>
>     futexes could be integrated into the higher layer (something at the same
>     level as the POSIX layer).  The userland LWKT, with kernel support, will
>     provide IPC mechanisms if the futex needs it, but this would not prevent
>     the futex code from spinning or spin/switching (in userland) on a mutex
>     if it wants to.
>
>     Also remember that I would eventually like to move the messaging 
>     implementation for system calls into an intermediate layer that is run
>     in userland but loaded by the kernel.  For now I'm not worried about
>     that, we can just have the system call messaging layer directly in libcr.

	Just for twinkles, I got half of the futex kernel part done
	today in the afternoon when I was bored out of my skull.  I am
	finding the kernel part much more simpler to do, and have put
	it into something called libfutex.  I shall work on this more,
	later on in the week.

	Btw, what did you think about adding a lib/ under sys/ ?

	Regards,

--
Hiten Pandya
hmp@xxxxxxxxxxxxx