--
Prof. George M. Sheldrick FRS
Dept. Structural Chemistry,
University of Goettingen,
Tammannstr. 4,
D37077 Goettingen, Germany
Tel. +49-551-39-3021 or -3068
Fax. +49-551-39-22582
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In my experience, writing efficient multithreaded code is much harder
than writing efficient
On 11/09/2011 11:53 AM, Francois Berenger wrote:
On 11/09/2011 07:21 PM, Pascal wrote:
I have more problems with L2 misse cache events and memory bandwidth. A
quad cores means 4 times the bandwidth necessary for a single process...
If your code is already a bit greedy, the scale up is not good.
On 11/09/2011 07:21 PM, Pascal wrote:
Le Tue, 8 Nov 2011 16:25:22 -0800,
Nat Echols a écrit :
On Tue, Nov 8, 2011 at 4:22 PM, Francois Berenger
wrote:
In the past I have been quite badly surprised by
the no-acceleration I gained when using OpenMP
with some of my programs... :(
You need big
Le Tue, 8 Nov 2011 16:25:22 -0800,
Nat Echols a écrit :
> On Tue, Nov 8, 2011 at 4:22 PM, Francois Berenger
> wrote:
> > In the past I have been quite badly surprised by
> > the no-acceleration I gained when using OpenMP
> > with some of my programs... :(
You need big parallel jobs and avoid sy
Thanks for pointing out that link. The graph makes the point I was going to
mention, i.e. that you notice a big difference in using up to about 4
processors for typical jobs, but after that point the non-parallelisable parts
of the code start to dominate and there's less improvement. This is v
See page 3 of this
http://www-structmed.cimr.cam.ac.uk/phaser/ccp4-sw2011.pdf
On Wed, 2011-11-09 at 09:22 +0900, Francois Berenger wrote:
> Hello,
>
> How faster is the OpenMP version of Phaser
> versus number of cores used?
>
> In the past I have been quite badly surprised by
> the no-accele
On Tue, Nov 8, 2011 at 4:22 PM, Francois Berenger wrote:
> In the past I have been quite badly surprised by
> the no-acceleration I gained when using OpenMP
> with some of my programs... :(
Amdahl's law is cruel:
http://en.wikipedia.org/wiki/Amdahl's_law
This is the same reason why GPU accelera
Hello,
How faster is the OpenMP version of Phaser
versus number of cores used?
In the past I have been quite badly surprised by
the no-acceleration I gained when using OpenMP
with some of my programs... :(
Regards,
F.
On 11/09/2011 02:59 AM, Dr G. Bunkoczi wrote:
Hi Ed,
in the CCP4 distribut
Hi Ed,
in the CCP4 distribution, openmp is not enabled by default, and there
seems to be no easy way to enable it (i.e. by setting a flag at the
configure stage).
On the other hand, you can easily create a separate build for phaser
that is openmp enabled and use phaser from there. To do this, cr
Could anyone point me towards instructions on how to get/build
parallelized phaser binary on linux? I searched around but so far found
nothing. The latest updated phaser binary doesn't seem to be
parallelized.
Apologies if this has been resolved before - just point at the relevant
thread, plea
Dear all,
it would be really great if someone could point out to me how to enable the
openmp option for phaser during the compilation of the latest ccp4 release.
The system will be a SUSE 11.3 64bit using gcc.
Cheers,
Jochen
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