#9321: Support for waiting on multiple MVars -------------------------------------+------------------------------------- Reporter: schyler | Owner: simonmar Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.8.3 Component: Runtime | Keywords: mvar System | Operating System: Unknown/Multiple Resolution: | Type of failure: None/Unknown Differential Revisions: | Test Case: Architecture: | Blocking: Unknown/Multiple | Difficulty: Unknown | Blocked By: | Related Tickets: | -------------------------------------+------------------------------------- Comment (by schyler): I have been hacking together a benchmark for STM (attached) first, then later I will put together the equivalent thing for MVar. On my i7 haswell macbook pro I compile and run it like this: {{{ $ ghc -O2 -threaded -fforce-recomp Bench.hs $ time ./Bench +RTS -N8 }}} This emulates the exact use case I mentioned for the server above, actually. We have * A packets queue, bounded, written and read by only 1 * An events chan, unbounded and written by everything (but individual forks) * A commands queue, bounded, written and read by 5% of the clients (but individual forks) In terms of the configurable parameters: * `threshold` is how many events, commands OR packets clients want before they just disconnect. I needed a fair simulation of throughput * `clients` is the number of clients to simulate connected to the server * There are adjustable delays on the client-local chans you can adjust, `packetDelay`, `eventDelay` and `commandDelay`. This is just to give a kind of estimate of the actual distribution of messages in a real server (I expect i.e. there to be 50 events per 1 actual client packet per 5 client-specific commands) Interestingly the bench terminates in 4 seconds when `clients = 20`. I set `clients = 40` and couldn't get it to terminate for over 5 minutes (and my laptop was really hot) so I killed it. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9321#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler