--------------------------------------------
-- stm-chans 1.2.0
--------------------------------------------
The stm-chans package offers a collection of channel types, similar to
Control.Concurrent.STM.TChan but with additional features.
--------------------------------------------
-- Changes (since 1.0.0)
--------------------------------------------
* (Version 1.1.0) Added tryWriteTBChan.
* (Version 1.1.0) Added tryWriteTBMChan.
* Some major performance improvements in TBChan and TBMChan, thanks to
Thomas DuBuisson. In particular, these improvements reduce contention
between readers and writers, improving throughput by up to 2--3 times
when producers and consumers are running in separate OS threads. The
cost for non-parallel programs is trivial (<1% worst-case running time,
per Criterion).
* Added estimateFreeSlotsTBChan, freeSlotsTBChan,
estimateFreeSlotsTBMChan, and freeSlotsTBMChan. These functions return
either the exact number or a lower-bound on the number of free slots
available before the channels will block/retry.
* Some other minor optimizations and code improvements.
--------------------------------------------
-- Long description
--------------------------------------------
In particular stm-chans offers these types:
* Control.Concurrent.STM.TBChan: Bounded FIFO channels.
When the channel is full, writers will block/retry. This ensures
that the writers do not get too far ahead of the readers, which helps to
make sure that memory and cpu resources are used responsibly.
* Control.Concurrent.STM.TMChan: Closeable FIFO channels.
This is like TChan (Maybe a) but with a monotonicity guarantee that
once Nothing is returned all future reads will be Nothing as well.
* Control.Concurrent.STM.TBMChan: Bounded Closeable FIFO channels.
This combines the capabilities of TBChan and TMChan.
In addition, the stm-chans package offers a (partial) compatibility
layer for some recent API improvements to the stm package (see ticket
#5104 [1]). These new functions include:
* tryReadTChan :: TChan a -> STM (Maybe a)
A version of readTChan which does not retry. Instead it returns
Nothing if no value is available.
* peekTChan :: TChan a -> STM a
Get the next value from the TChan without removing it, retrying if
the channel is empty.
* tryPeekTChan :: TChan a -> STM (Maybe a)
A version of peekTChan which does not retry. Instead it returns
Nothing if no value is available.
[1] http://hackage.haskell.org/trac/ghc/ticket/5104
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-- Links
--------------------------------------------
Homepage:
http://code.haskell.org/~wren/
Hackage:
http://hackage.haskell.org/package/stm-chans
Darcs:
http://community.haskell.org/~wren/stm-chans
Haddock (Darcs version):
http://community.haskell.org/~wren/stm-chans/dist/doc/html/stm-chans
--
Live well,
~wren
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