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Old 2020-05-20, 19:26   #1
dlsilver06
 
Apr 2020

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Default Am I using machines effectively?

Have 2 laptops
#1 is older P6100 @2GHz, 2 cores, 4GB RAM. Current memory settings 100MB day & night. Using task manager, it's running at ~97-99% CPU. Just doing double-checking so far.
#2 is newer i5-7200U @ 2.5GHz, 2 hyperthreaded cores, 8GB RAM. Memory at 1000 / 4000. It runs at about 50% CPU. Does mix of double-checking and PRP.

Is there something I should set differently to get #2's usage higher, or is this just how the hyperthreaded cores work? Just want to work as efficiently as possible.
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Old 2020-05-20, 19:38   #2
kriesel
 
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Quote:
Originally Posted by dlsilver06 View Post
Is there something I should set differently to get #2's usage higher, or is this just how the hyperthreaded cores work? Just want to work as efficiently as possible.
Thanks for whatever DC you can contribute. The i5-7200U is 2 cores 4 threads. You're doing fine as is. The usual recommendation is to run prime95 without hyperthreads, using only as many cores as there are. Windows counts by hyperthreads so shows 50% for full utilization of a hyperthreaded processor.

These GIMPS computations are usually memory-access-speed bound, so more processor registers does not help much. Sometimes, depending on processor and task, a little more performance can be obtained by running with hyperthreads. You can benchmark both ways and make an informed choice. Options, benchmark, in prime95. What's maximum performance can vary by number of workers and fft length (exponent size). If you are concerned about power efficiency, that gets a little more involved. https://ark.intel.com/content/www/us...-3-10-ghz.html
You could consider also running mfakto on the HD620 IGP. In my experience that yields about 18GhzD/day of trial factoring progress, and reduces the cpu-side throughput by about half on an i7-7500U. The IGP and cpu share a package TDP limit, and also memory access. See http://www.mersenneforum.org/showpos...91&postcount=2 and https://www.mersenneforum.org/showthread.php?t=23394

Last fiddled with by kriesel on 2020-05-20 at 19:49
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Old 2020-05-21, 08:59   #3
S485122
 
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Quote:
Originally Posted by dlsilver06 View Post
Have 2 laptops
#1 is older P6100 @2GHz, 2 cores, 4GB RAM. Current memory settings 100MB day & night. Using task manager, it's running at ~97-99% CPU. Just doing double-checking so far.
#2 is newer i5-7200U @ 2.5GHz, 2 hyperthreaded cores, 8GB RAM. Memory at 1000 / 4000. It runs at about 50% CPU. Does mix of double-checking and PRP.

Is there something I should set differently to get #2's usage higher, or is this just how the hyper-threaded cores work? Just want to work as efficiently as possible.
Not really your question but the memory settings in Prime95 do not apply to LL or PRP work but to P-1 and ECM work. See the readme.txt file that comes with Prime95. The readme.txt that comes with mprime has not yet been updated to reflect the current range of exponents.

Jacob
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Old 2020-05-21, 10:06   #4
garo
 
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Turn off hyper-threading. Run benchmarks to see if you will be better off running 1 worker on two cores rather than 2 workers on 2 cores. I have a 7500U and I found I got slightly more throughput running a single worker.
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Old 2020-05-21, 12:56   #5
kriesel
 
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Quote:
Originally Posted by garo View Post
Turn off hyper-threading. Run benchmarks to see if you will be better off running 1 worker on two cores rather than 2 workers on 2 cores. I have a 7500U and I found I got slightly more throughput running a single worker.
To clarify, disable use of hyperthreading for primality testing in prime95, if benchmarking shows that's the right course. Having hyperthreading available to support other system activity will preserve prime95 performance.
Tabulated results of thorough benchmarking for a variety of cpu types can be found at https://www.mersenneforum.org/showpo...18&postcount=4 and https://www.mersenneforum.org/showpo...19&postcount=5

Last fiddled with by kriesel on 2020-05-21 at 13:31
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