[Tsung] Enabling kernel poll support

[Vinod Panicker]

On 5/16/07, Nicolas Niclausse <nicolas at niclux.org> wrote:
> Vinod Panicker wrote:
>
> > I'm using tsung to generate a huge number of concurrent users on a
> > jabber server.  I believe that enabling kernel poll support should
> > significantly improve the cpu utilization on the client machines.
>
> It should if you have lots of users in a each beam
>
> > How do I go about doing that?  I've added '+K true' in the tsung shell
> > script -
> >
> > ERL_OPTS=" +A 1 -shared +K true  "
>
> > But how do I verify whether this option is being used or not?  I'm
> > running tsung in a distributed fashion.  All client machines support
> > kernel poll, as verified by starting erl with +K true shows it to be
> > enabled.
>
> The option will only be used on the controller and will not be
> propagated to remote clients. This patch should fix the problem:
>
> --- ts_config_server.erl        (revision 721)
> +++ ts_config_server.erl        (working copy)
> @@ -354,6 +354,7 @@
>          " -boot_var ", ?TSUNGPATH, " ",PathVar,
>          " -pa ", PA1,
>          " -pa ", PA2,
> +        " +K true ",
>          " -tsung debug_level ", integer_to_list(?config(debug_level)),
>          " -tsung dump ", atom_to_list(?config(dump)),
>          " -tsung log_file ", LogDir

Thanks!  Let me give this a try.  Without kernel poll support we are
able to generate only 3k users from a 2 Ghz Athlon with 1 GB RAM.

Jason, kernel poll is the erlang equivalent of enabling 'poll'
variants on supported platforms such as Linux, Solaris etc.  Linux has
support for epoll, whereas Solaris I believe has /dev/poll.  Try
starting the erlang shell this way -

prompt$ erl +K true

If you see [kernel-poll:true] being printed, it means erlang can
support kernel poll on the machine.  Running with this option enabled
should result in much better performance, even 4x improvement or more.

BTW, what server are you benchmarking?

Regards,
Vinod.

PS: +1 for the list reply-to re-configuration