Hello Charles,

MRG is a redhat product for Messaging/Realtime/Grid. They've packaged all this together for use with financial applications, but its only the realtime bit which has most use for scientific applications (possibly messaging).

SL5 distros are here: 
http://glitesoft.cern.ch/cern/mrg/slc5X/i386/RPMS/repoview/mrg-realtime.group.html

We manually patched CentOS 5 with the realtime kernel (i.e. without this RPM) and did some speed trials. Generally, it works very well, although not 100% deterministic/guaranteed. 

The trial machine was a dual Xeon X5550 2.66GHz (8 CPU cores). Without the RT kernel, we averaged 1ms thread wakeup/latency. With the RT kernel, this dropped to typical 5uS latency, but with occasional 'spikes' up to 60uS. I suspect these spikes are due to the processors NMI/SSI interrupts kicking in, which there is little the kernel can do about. 

The real killer test was running again with Hyperthreading enabled. This gives a total 16 virtual CPU's. Without RT, latency was 1.04mS. With RT this dropped to 8uS average, but spiking up to 134uS. 

Mat

-----Original Message-----
From: Charles ELSAESSER WebmailOrange [mailto:[log in to unmask]] 
Sent: 13 May 2011 11:04
To: Mathew Maher
Cc: [log in to unmask]
Subject: re: MRG / Realtime with SL6

Bonjour,

It would have been nice and usefull
if you had given links to packages, docs, patches for kernel-rt (et al) packages available for SLXXX if you know them.

What does MRG stands for?

Thank you.

Charles

--------------
> Message du 13/05/11 10:20
> De : "Mathew Maher" 
> A : [log in to unmask]
> Copie à : 
> Objet : MRG / Realtime with SL6
> 
> Hi Guys,
> Has anyone attempted to patch SL6 into realtime yet?
> 
> I'm specifically referring to the kernel-rt (et al) packages available 
> ...

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