lkwt in DragonFly

David Xu davidxu at
Mon Feb 9 01:16:12 PST 2004

Matthew Dillon wrote:
:Your explanation is interesting, I am sorry that I am new to DFly,
:but if two threads on same CPU wants to exclusivly access a data 
:structure, what lock should be used ? does token still work ? on
:FreeBSD, one can use mutex, but token is holden by CPU on DFly not by 
:thread, so a thread really does not know if it already held the lock
:or not, although its CPU already hold the token.
:David Xu

    If you want something that stays valid through a switch or a blocking
    condition then you would need to use a lockmgr lock.  If you just
    need atomicy across a short period of time in which you know the
    thread will not block, or in a situation where the code does the 
    right thing if another piece of code operates on the same
    data structure while the first piece is blocked, then a token
    would be sufficient.

That's the thing I need, thanks !

And sorry a bit OT, what's the plan of pthread supports in DFly, I am
very interested to work on it in near future.
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>
David Xu

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