Hi Paul, I've disabled HT on thing03 and re-provisioned it with RHEL7. I likely won't have time for a while to get RHEL7 on Dowd. Ben

On May 5, 2015, at 9:20 PM, Paul Romano <[email protected]> wrote:

Hal,

Thanks for pointing out /opt/at7.0 -- worked great!

Best, Paul

On Tue, May 5, 2015 at 10:29 PM, Hal Finkel <[email protected]> wrote: Hi Paul, Ben,

I would certainly not object to having a newer base OS on dowd, although we currently do have some newer compilers installed. There are newer compilers installed in: /opt/at7.0/bin/

and you can also use the one in my home directory: /home/hfinkel/install/ppc64/gcc/bin

Turning off HT for a few days is fine by me. Please let me know when you're doing it, so that I won't disturb your benchmarks.

-Hal

----- Original Message -----

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From: "Paul Romano" <[email protected]> To: "Benjamin S. Allen" <[email protected]> Cc: [email protected], "Hal J. Finkel" <[email protected]> Sent: Tuesday, May 5, 2015 10:20:27 AM Subject: Re: [JLSE-Admins] Hardware threading on thing nodes

Thanks Ben. RHEL6 or 7 are fine, so whatever is easiest. GCC 4.8.2 would be sufficient for my needs on dowd.

Paul

On Tue, May 5, 2015 at 10:05 PM, Allen, Benjamin S. < [email protected] > wrote:

Hi Paul,

Yea its possible get a thing node with HT disabled. I'll likely grab thing03 for this. Hopefully I'll find some time today to change the BIOS setting. Do you want RHEL6 or 7 on the box?

We don't have XL licenses unfortunately. If there's a newer version on IBM's website I can re-install the eval and get another 90 days out of it.

We can also look at installing RHEL7 on the box, which has GCC 4.8.2. Hal Finkel (cc'ed) is the primary user of Dowd, so he'll need to weigh in on what we should do.

Ben

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On May 4, 2015, at 10:25 PM, Paul Romano < [email protected]

...

wrote:

Hi Ben,

Just wanted to ping you on this. Do you think it will be possible to get a thing node with HT disabled for a day or two?

Also, an unrelated question -- I saw there is an IBM XL compiler on dowd, but it does not have a valid license. Is there another compiler that works on that node? I need something a little more recent than the default gcc 4.4. I've tried unsuccessfully to build a more recent version of gcc.

Thanks, Paul

On Mon, Apr 27, 2015 at 4:00 PM, Paul Romano < [email protected] > wrote: Hi Ben,

One aspect of the study I'm performing is to look at any potential differences between the situation you just described, i.e. only using as many threads as there are physical cores with HT enabled, and actually disabling HT altogether, so unfortunately binding to the first hardware thread won't suffice. Once I have everything scripted and ready to go, it shouldn't take more than a day or two to perform the actual runs.

Best, Paul

On Sun, Apr 26, 2015 at 9:54 PM, Allen, Benjamin S. < [email protected] > wrote: Hi Paul,

Will running your application with taskset or numactl suffice, eg: taskset -c 0-35 cmd or numactl -C 0-35 cmd? Thus pinning the application to the first hardware thread on each core.

If not how long do you think you'll need a machine with HT disabled?

Ben

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On Apr 25, 2015, at 7:31 AM, Paul Romano < [email protected] > wrote:

Hi,

I'm currently doing some studies on the impact of hardware threading on code performance for nuclear reactor neutronic calculations. I was wondering if it might be possible to have one of the thing nodes configured with hardware threading disabled for the sake of running comparisons.

Thanks, Paul

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-- Hal Finkel Assistant Computational Scientist Leadership Computing Facility Argonne National Laboratory