[vlc] Re: ["Lopez, A." <a.lopez at tue.nl>] RE: Re: VLC number of simultaneous streams

[Viktor Kompaneyets]

System administration wrote:
> From: "Lopez, A." <a.lopez at tue.nl>
> Date: Tue, 15 Nov 2005 14:33:29 +0100
> To: vlc at videolan.org
> Subject: RE: [vlc] Re: VLC number of simultaneous streams
> 
>> > I have managed to (UDP) stream up to 20 videos simultaneously
> without
>> > problems.
>> Probably worth looking at your disk subsystem. What bitrate are the
>> movies?
>> High quality broadcast streams, say 4Mbps require 0.5MBytes per
> second.
>> Even
>> on high end machines, unless special measures are taken, standard OS
> disk
>> reading will not work well at high stream counts.
> 
> Indeed the movies are at 4Mbps.

HDD what type do you're using? For such count of simultaneous reading you
need high-end SCSI subsystem. 

> Some time ago I installed MRTG to check the performance of the servers.
> I have attached the graphs that were generated during those tests. The
> first graphs shows the traffic coming out of the server (during the test
> where the server streamed 20 streams, which corresponds to the second
> pick, it reaches a maximum value of about 12 Mbytes/sec).

In other words - 100Mbit/s, looks like hardware (network) bottleneck?

> The second graph shows CPU usage (reaches a maximum value of 38%).
> The third graphs shows swap memory usage and you can see that, when the
> vlc starts having problems (trying to stream more than 20 videos), the
> swap space is massively used (more than 1.5 GB). On the other hand, when
> streaming e.g. 15 videos, the swap space is not used at all.

It's normal. 15x4=60Mbit/s, looks great for 100Mbit/s NIC. Have you
investigated, which process goes to swap?

> 
> The server is a P4-2.8GHz, 512RAM, 80GB HDD.

My presumption - is there an SATA HDD?

> 
> Do you have any explanation for this behaviour?

See above

> PS. How can I check the disk subsystem?

It depends on what kind of distro do you have.

-- 
Viktor Kompaneyets
Wnet project manager

-- 
This is the vlc mailing-list, see http://www.videolan.org/vlc/
To unsubscribe, please read http://www.videolan.org/support/lists.html