1. TAME – Event Style Programming with Threads
Threads vs. Events
TAME – Event Style Programming with Threads
5204 – Operating Systems

2. implemented via source-source translation avoids stack ripping
TAME
expressive abstractions for event-based programming
implemented via source-source translation
avoids stack ripping
type safety and composability via templates
M. Krohn, E. Kohler, M.F. Kaashoek, “Events Can Make Sense,” USENIX Annual Technical Conference, 2007, pp
CS 5204 – Operating Systems

3. A typical thread programming problemf
(blocking, synchronous operation, e.g., I/O) c
Problem: the thread becomes blocked in the called routine (f) and the caller (c) is unable to continue even if it logically is able to do so.
CS 5204 – Operating Systems

4. A partial solution c f Issues
(non-blocking, asynchronous operation, e.g., I/O)
register
handler
(signal + data)
Issues
Synchronization: how does the caller know when the signal has occurred without busy-waiting?
Data: how does the caller know what data resulted from the operation?
CS 5204 – Operating Systems

5. A “Tame” solution c f <I> <T> <I> <T> e r:
(1)
(2)
(4)
(3)
(5)
(non-blocking, asynchronous operation, e.g., I/O)
(10)
(11)
<I> r:
slot
<T> a;
(9)
e(a):
<T>
handler
(7)
e.trigger(data)
a <- data
(8)
(signal + data)
(6)
<I>
rendezvous<I>
<T>
event<T>
wait point
CS 5204 – Operating Systems

6. Tame Primitives
CS 5204 – Operating Systems

7. An example tamed gethost_ev(dsname name, event<ipaddr> e);
CS 5204 – Operating Systems

8. Variations on control flow
parallel control flow
window/pipeline
control flow
CS 5204 – Operating Systems

9. Event IDs & Composability
CS 5204 – Operating Systems

10. Closures
f( …params…) {
rendezvous<> r;
tvars { …locals…};
twait(r);
continue_here: }
copy
copy
closure r:
Smart pointers and reference counting insure correct deallocation of events, redezvous, and closures.
CS 5204 – Operating Systems

11. Performance (relative to Capriccio)
CS 5204 – Operating Systems