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Diffstat (limited to '075channel.mu')
| -rw-r--r-- | 075channel.mu | 18 |
1 files changed, 5 insertions, 13 deletions
diff --git a/075channel.mu b/075channel.mu index 1f8248ef..422b2ab8 100644 --- a/075channel.mu +++ b/075channel.mu @@ -1,18 +1,11 @@ # Mu synchronizes between routines using channels rather than locks, like # Erlang and Go. # -# Key properties of channels: +# The key property of channels: Writing to a full channel or reading from an +# empty one will put the current routine in 'waiting' state until the +# operation can be completed. # -# a) Writing to a full channel or reading from an empty one will put the -# current routine in 'waiting' state until the operation can be completed. -# -# b) Writing to a channel implicitly performs a deep copy. This prevents -# addresses from being shared between routines, and therefore eliminates all -# possibility of race conditions. -# -# There's still a narrow window for race conditions: the inputs passed in -# to 'start-running'. Pass only channels into routines and you should be fine. -# Any other mutable inputs will require locks. +# Beware of addresses passed into channels. They can cause race conditions. scenario channel [ run [ @@ -92,8 +85,7 @@ def write out:&:sink:_elem, val:_elem -> out:&:sink:_elem [ # store a deep copy of val circular-buffer:&:@:_elem <- get *chan, data:offset free:num <- get *chan, first-free:offset - val-copy:_elem <- deep-copy val # on this instruction rests all Mu's concurrency-safety - *circular-buffer <- put-index *circular-buffer, free, val-copy + *circular-buffer <- put-index *circular-buffer, free, val # mark its slot as filled free <- add free, 1 { |