[Beowulf] Quadrics?

[Vincent Diepeveen]

On Apr 5, 2011, at 7:52 AM, Beat Rubischon wrote:

> Hi Vincent!
>
> On 04.04.11 21:16, Vincent Diepeveen wrote:
>> latency is superior of quadrics compared to all the infini* stuff.
>
> Quadrics was great stuff - but it was outperformed once Mellanox  
> invited
> their ConnectX chips. Additional the Quadrics team never got their  
> PCIe
> chips (QSnet III) to fly. Finally the company closed their doors in  
> may 09.
>
> I really liked their hard- and software. But the time is over...
>

of course there is new great pci-e solutions, yet the price per port  
there is
bigger than entire machine with latest gpu, that's a big problem to  
make cheap
clusters.

If you buy a cheap 6 core box of 350 euro then a new generation gpu is
318 euro or so  (that's a HD6970).

What's node price of the network?

>> Of course even the realtime linux kernel is rather crappy there, as
>> it locks every action from and to a socket (even RAW/UDP
>> communication in fact), so you need a 'hack' of that kernel anyway to
>> get faster latencies.
>
> When talking about Interconnects the kernel is not involved in
> communication. Any context switch is avoided to keep the overhead  
> small.
> This basically means a real time kernel isn't needed as it would not
> give you any additional benefit.

realtime kernel keeps other worst cases down bigtime, especially with  
respect to
scheduling.

>
> Beat
>
> -- 
>      \|/                           Beat Rubischon <beat at 0x1b.ch>
>    ( 0-0 )                             http://www.0x1b.ch/~beat/
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