[Haskell-cafe] Re: sendfile leaking descriptors on Linux?

[Thomas DuBuisson]

Bardur Arantsson <spam at scientician.net> wrote:
>> ...
>>       then do errno <- getErrno
>>               if errno == eAGAIN
>>                 then do
>>                    threadDelay 100
>>                    sendfile out_fd in_fd poff bytes
>>                 else throwErrno "Network.Socket.SendFile.Linux"
>>      else return (fromIntegral sbytes)
>
> That is, I removed the threadWaitWrite in favor of just adding a
> "threadDelay 100" when eAGAIN is encountered.
>
> With this code, I cannot provoke the leak.
>
> Unfortunately this isn't really a solution -- the CPU is pegged at
> ~50% when I do this and it's not exactly elegant to have a hardcoded
> 100 ms delay in there. :)

I don't think it matters wrt the desired final solution, but this is
NOT a 100 ms delay.  It is a 0.1 ms delay, which is less than a GHC
time slice and as such is basically a tight loop.  If you use a
reasonable value for the delay you will probably see the CPU being
almost completely idle.

Thomas