[Halld-online] hyper threads on gluon47-gluon51

[David Lawrence]

Hi Paul,

  It is not time critical, but we should probably take care of it before we forget about it. I’m CC-ing this discussion to the halld-online mailing list so anyone working on gluon47-gluon51 can speak up if rebooting one of these will cause them problems right now.

 For the sake of scheduling, I suggest a time for doing this as first thing Thursday morning where “first thing” means whenever Paul comes in. I assume it will only take a few minutes per node. Paul, if this doesn’t work for you, please suggest another time. If anyone else needs this procedure to happen at a later time, let Paul and me know when a better time would be.

Regards,
-David


On May 14, 2014, at 11:22 AM, Paul Letta <letta at jlab.org> wrote:

> I checked out gluon52.  It was showing 16 logical CPUs... and they all had the HT flag set.
> I took it down to BIOS and found HT was disabled.   I enabled it.
> It now shows 32 logical CPUs.
> 
> So we will need to plan a time that I can walk through the EMUs and fix them.
> 
> Paul
> 
> 
> 
> From: "Paul Letta" <letta at jlab.org>
> To: "David Lawrence" <davidl at jlab.org>, "David Abbott" <abbottd at jlab.org>
> Cc: "Hovanes Egiyan" <hovanes at jlab.org>
> Sent: Friday, May 9, 2014 11:48:46 AM
> Subject: Re: hyper threads on gluon47-gluon51
> 
> They all have 16 cores each.  So if HT is on, they should show as 32 cpus.. 
> gluon46-52 (16 core EMUs)  (7 servers)
> gluon104-111 (16 core farms) (8 servers)
> 
> should all show the same.
> 
> Did the HT get turned off on 47-51 because they are EMUs maybe?
> 
> Let me know, and I will be happy to go through them and turn HT on everywhere..
> 
> Also note: gluon53 is the 32 core AMD box -- no HT with it.
> 
> Paul
> 
> 
> 
> From: "David Lawrence" <davidl at jlab.org>
> To: "Paul Letta" <letta at jlab.org>
> Cc: "Hovanes Egiyan" <hovanes at jlab.org>
> Sent: Friday, May 9, 2014 10:53:36 AM
> Subject: hyper threads on gluon47-gluon51
> 
> Hi Paul and Hovanes,
> 
>   When I look at gluon47-gluon51, I’m not seeing as many “processors” as I expect. These all show a total of 16 processors with the “ht” flag present. I assumed the “ht” flag meant that hyper threading was enabled. However, these machines indicate each core is in a group of only 8 siblings while for gluon46 as well as gluon104-gluon111, they indicate there are 16 siblings and a total of 32 processors (half of which I assume are real cores and the other half hyper threads). Paul, can you confirm that hyper threading is turned on for all of these nodes? Or, is there a reason it is off?
> 
> Regards,
> -David
> 
> 

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