[Haskell-cafe] Slow mvar when compiled with threaded

[Branimir Maksimovic]

On 01/10/2014 01:03 AM, Bob Ippolito wrote:
>
> The bad news is that the fix is to compile it with GHC HEAD (~7.8, I 
> built ec4af3f), which has the new Mio high-performance multicore IO 
> manager [1]. Apparently the old IO manager wasn't well suited to this 
> use case.
>
> With the latest GHC, the -threaded version outperforms the single 
> threaded version, and the numbers for both are better than with GHC 7.6.3.
>
Thanks. Glad to hear that!