[Nek5000-users] Parallel speedup on supercomputer Tianhe-2

[nek5000-users at lists.mcs.anl.gov]

Dear Stefan,

Sorry, I didn't make myself clear. What I meant is whether we can further
improve the parallel computing performance, as I am only using about 1/3 of
the computing power of each node. Thank you very much!

Best regards,
Wei XU

Date: Wed, 07 Dec 2016 12:01:42 +0100
From: nek5000-users at lists.mcs.anl.gov
To: <nek5000-users at lists.mcs.anl.gov>
Subject: Re: [Nek5000-users] Parallel speedup on supercomputer
        Tianhe-2
Message-ID:
        <mailman.7291.1481108507.3602.nek5000-users at lists.mcs.anl.gov>
Content-Type: text/plain; charset="utf-8"

Why do think something is wrong i.e. you have a problem?

From: <nek5000-users-bounces at lists.mcs.anl.gov> on behalf of <
nek5000-users at lists.mcs.anl.gov>
Reply-To: <nek5000-users at lists.mcs.anl.gov>
Date: Wednesday, December 7, 2016 at 10:39 AM
To: <nek5000-users at lists.mcs.anl.gov>
Subject: Re: [Nek5000-users] Parallel speedup on supercomputer Tianhe-2

Dear Stefan,

Thank you very much! Can I do anything on the Nek5000 side to reduce the
problem?

Best regards
Wei XU

Date: Tue, 6 Dec 2016 16:34:04 +0100
From: nek5000-users at lists.mcs.anl.gov
To: nek5000-users at lists.mcs.anl.gov
Subject: Re: [Nek5000-users] Parallel speedup on supercomputer
        Tianhe-2
Message-ID:
        <mailman.7242.1481038500.3602.nek5000-users at lists.mcs.anl.gov>
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That'a reasonable. The core compete for shared resources (L3 and DDR).

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Date: Tue, 6 Dec 2016 16:25:22 +0800
From: nek5000-users at lists.mcs.anl.gov
To: nek5000-users at lists.mcs.anl.gov
Subject: Re: [Nek5000-users] Parallel speedup on supercomputer
        Tianhe-2
Message-ID:
        <mailman.7221.1481012750.3602.nek5000-users at lists.mcs.anl.gov>
Content-Type: text/plain; charset="utf-8"

Dear Stefan,

Thank you for your reply. There are 139056 elements and the polynomial
order is 7 (lx1=8).  I measure the solver time to compute the speedup. For
example, the serial job takes 2564.59s and the same job with 24 tasks takes
302.18s. The speedup is about 8.5. This is on a single Tianhe-2 node. The
speedup between nodes is quite good.

I also test the code on my 36-core computer (Dual Xeon E5 18-Core). I can
only get about 12 times speedup when I use 36 tasks. It is also about 1/3.

Best regards,
Wei XU
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