Max number of open file descriptors is too low

Joel Reymont <>
Tue Sep 27 16:16:53 CEST 2005


This won't work on Unix. Assuming that MAX_FILES() will return  
ERL_MAX_PORTS, it will be reset back to FD_SETSIZE. I had this  
problem on the Mac and had to edit header files.

Could this be a bug?

 From erts/emulator/unix/sys.c

void
erl_sys_init(void)
{
...
     if ((max_files = MAX_FILES()) < 0)
         erl_exit(1, "Can't get no. of available file descriptors\n");

     /* Note: this is if MAX_FILES() differ from FD_SETSIZE which it */
     /* does by deafult on e.g. BSDI  */
#if defined(USE_SELECT) && defined(FD_SETSIZE)
     if (max_files > FD_SETSIZE)
         max_files = FD_SETSIZE;
#endif
..
}


On Sep 27, 2005, at 4:06 PM, Bengt Kleberg wrote:

> On 2005-09-27 15:46, Joel Reymont wrote:
>
>> Folks,
>> Erlang hardcodes the maximum number of open file descriptors and  
>> I  think the default number is too low. At least on Windows it is.
>>
>
> ...deleted
>
>> Would the Erlang/OTP consider upping the number of descriptors on   
>> Windows to something like 1024*8 or 1024*10?
>>
>
> greetings,
>
> have you tried this:
>
> (http://www.erlang.se/doc/doc-5.4.8/doc/efficiency_guide/ 
> part_frame.html)
>
> Open files, and sockets
>     The maximum number of simultaneously open files and sockets  
> depend on the maximum number of Erlang ports available, and  
> operating system specific settings and limits.
>
> Open ports
>     The maximum number of simultaneously open Erlang ports is by  
> default 1024. This limit can be raised up to at most 268435456 at  
> startup (see environment variable ERL_MAX_PORTS in erlang(3)) The  
> maximum limit of 268435456 open ports will at least on a 32-bit  
> architecture be impossible to reach due to memory shortage.
>
>
> bengt
>
>

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