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2020-10-23, 14:06   #23
piforbreakfast

Oct 2020
Terre Haute, IN

2E16 Posts

Quote:
 Originally Posted by Uncwilly Using Prime95 just go into "Test"->"Worker Windows" on the menu. Then "Type of work to get" select "First time prime tests". To get the most tests done by the machine overall, generally most people run 2 to 4 workers total and each with 2-4 cores, depending on the number of CPU.cores and on chip cache. Use "Options"->"Benchmarks" to see what works well. Often times having the machine work on more numbers at once give more output overall, than working on only one at a time.
So far I've just had my computer doing one job at a time, with what I'm guessing is pretty fast speed on an Intel 10900 processor. How much would it slow down each job? Or am I worrying too much about straining processor speed at this point, especially since I have nothing else on my computer?

 2020-10-23, 14:09 #24 piforbreakfast   Oct 2020 Terre Haute, IN 568 Posts And now I changed the settings to add a second worker and start a second job, but for some reason the window for the second worker is not coming up. I'm only seeing the window for my first job that was in progress.
2020-10-23, 14:15   #25
piforbreakfast

Oct 2020
Terre Haute, IN

2×23 Posts

Quote:
 Originally Posted by piforbreakfast And now I changed the settings to add a second worker and start a second job, but for some reason the window for the second worker is not coming up. I'm only seeing the window for my first job that was in progress.
OK, I figured out how to make a window come up for the second worker, but it isn't starting a job yet. The window says Worker #2 at the top but the window itself is totally blank.

Last fiddled with by piforbreakfast on 2020-10-23 at 14:16

2020-10-23, 14:53   #26
Viliam Furik

Jul 2018
Martin, Slovakia

5·53 Posts

Quote:
 Originally Posted by piforbreakfast So far I've just had my computer doing one job at a time, with what I'm guessing is pretty fast speed on an Intel 10900 processor. How much would it slow down each job? Or am I worrying too much about straining processor speed at this point, especially since I have nothing else on my computer?
As Uncwilly said: "Often times having the machine work on more numbers at once give more output overall, than working on only one at a time."

The throughput of each job would go down almost proportionally to the number of jobs --> If you have one job at a time, its speed is x. If you have 2, the speed of each one should be x/2, plus some little gain, which increases the total throughput when you sum the n speeds for n jobs.

It also depends on the chip structure. Intel chips have one big hot heating plate instead of a die, which contains everything - all the cores, cache, I/O, etc. Because of that, the fact Intel is greedy with L3 cache, it boosts a lot higher when using 1 core, lower when 2, etc., boost doesn't last long (AFAIK), and all the cores are on one die, together with all the little cache, it behaves differently than AMD - a lot of L3 cache, good for Prime95, because it doesn't have to use the slower RAM, more limited boost range but sustains the boost, but cores are subdivided to chiplets and cache-eating groups (worse for Prime95 because of added latency). IMHO, AMD (especially Ryzen 9 3900X, 64GiB of L3 cache - good for current first-time check wavefront, 12 cores, and now a really good price) is better for prime hunting, not only because the numbers on FTC range show it, but also it doesn't eat as much electricity when left unattended - lower temperatures, and electricity bills.

So yeah, 10900 pretty fast, but 3900X is pretty a lot faster, at least in the FTC range, which is what you want to do.

And as others asked before, what is the graphics card (GPU) in your computer? GPUs are really good for trial factoring and help the search a lot by identifying the composite candidates without the need for the long test.

2020-10-23, 15:57   #27
Runtime Error

Sep 2017
USA

B716 Posts

Quote:
 Originally Posted by piforbreakfast So far I've just had my computer doing one job at a time, with what I'm guessing is pretty fast speed on an Intel 10900 processor. How much would it slow down each job? Or am I worrying too much about straining processor speed at this point, especially since I have nothing else on my computer?
The easiest way to check is to run benchmarks. Within Prime95: Options --> Benchmark. Go to the "Number of workers to benchmark" box and put "1,2" (without the quotes). Put all cores, and put a minimum/maximum FFT sizes in a window around 5500K, which is about the length for current first-time tests. It will quickly tell you whether or not you should run 2 workers.

(I have not found multiple workers better on retail Intel CPUs.)

Edit: Also, since you just got the machine, you might want to check that your RAM has its XMP profile running. RAM speed is a big factor for Prime95.

Last fiddled with by Runtime Error on 2020-10-23 at 16:01

 2020-10-23, 16:14 #28 kriesel     "TF79LL86GIMPS96gpu17" Mar 2017 US midwest 11×433 Posts Amen on benchmarks. What's optimal in prime95 depends on both hardware details and on what you run on it; big exponents or small or medium, for example. See https://www.mersenneforum.org/showth...218#post504218 and https://www.mersenneforum.org/showpo...19&postcount=5 for some analyzed examples for assorted hardware. Last fiddled with by kriesel on 2020-10-23 at 16:15
 2020-10-23, 23:46 #29 piforbreakfast   Oct 2020 Terre Haute, IN 4610 Posts OK, I'm confused...I've had a job going for some time and just noticed a notation in the work progress window from about an hour ago that the primality test on the file in progress was stopped for some reason, and the next line says "restarting worker to do priority work/stopping primality test of m58700879" even thought the job was about 73 percent complete, and now another job is running. Also, I just notice in another window for worker #2 a line that says "insufficient memory to ever run stage 2." Is Primenet using that much memory on my 1TB hard drive?
2020-10-24, 00:03   #30
Uncwilly
6809 > 6502

"""""""""""""""""""
Aug 2003
101×103 Posts

8,941 Posts

Quote:
 Originally Posted by piforbreakfast OK, I'm confused...I've had a job going for some time and just noticed a notation in the work progress window from about an hour ago that the primality test on the file in progress was stopped for some reason, and the next line says "restarting worker to do priority work/stopping primality test of m58700879" even thought the job was about 73 percent complete, and now another job is running.
Don't Panic!
What is happening is that you are doing the Cert run for that exponent. It will be quick and you will be right back on the other test. Because the files for these proofs are large, we don't want them hanging around on the server. They have to stay there until the work is returned as complete (otherwise it has to get handed out to someone else.) This is normal.

Quote:
 Also, I just notice in another window for worker #2 a line that says "insufficient memory to ever run stage 2." Is Primenet using that much memory on my 1TB hard drive?
Sounds like you are doing P-1 (or ECM) testing. No, it is not the hard disk, rather RAM. And it is the setting that is an issue. In the Prime95 menu go to "Options"->"Resource Limits and Settings", tap "Advanced". Set Daytime and Nighttime memory setting to at least 0.2 GB, 0.5 should be enough. Don't let it have more than can be reasonably spared.

2020-10-24, 00:12   #31
piforbreakfast

Oct 2020
Terre Haute, IN

2·23 Posts

Quote:
 Originally Posted by Uncwilly Sounds like you are doing P-1 (or ECM) testing. No, it is not the hard disk, rather RAM. And it is the setting that is an issue. In the Prime95 menu go to "Options"->"Resource Limits and Settings", tap "Advanced". Set Daytime and Nighttime memory setting to at least 0.2 GB, 0.5 should be enough. Don't let it have more than can be reasonably spared.
I just changed the settings. I'll keep you posted on the performance.

2020-10-24, 01:11   #32
kriesel

"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest

11·433 Posts

Quote:
 Originally Posted by Uncwilly Don't Panic! What is happening is that you are doing the Cert run for that exponent. It will be quick and you will be right back on the other test. Because the files for these proofs are large, we don't want them hanging around on the server. They have to stay there until the work is returned as complete (otherwise it has to get handed out to someone else.) This is normal. Sounds like you are doing P-1 (or ECM) testing. No, it is not the hard disk, rather RAM. And it is the setting that is an issue. In the Prime95 menu go to "Options"->"Resource Limits and Settings", tap "Advanced". Set Daytime and Nighttime memory setting to at least 0.2 GB, 0.5 should be enough. Don't let it have more than can be reasonably spared.
Go bigger if it won't get in the way of other things. And make day and night values the same to avoid restarts of stage 2 when the limits change with the time of day.

George's example is for 6GB. It will use 20+GB on 100M exponents if it's available.

For such questions, the included documentation is useful. From readme.txt:
Code:
Daytime and nighttime P-1/ECM stage 2 memory
--------------------------------------------

On occasion, you may be assigned an exponent that needs P-1 factoring prior to running a
primality test.  Or you might have chosen to do P-1 or ECM work (possibly because you do
not want to devote disk space for large PRP files).  In these situations, the program can
do stage 2 slightly more effectively if it is given more memory to work with.  However,
if you let the program use too much memory then the performance of ALL programs will suffer
due to thrashing.

That is, most of the time this setting is not used and even with minimal settings the program
will work just fine.  Should you decide to change these settings, how do you choose intelligently?
Below are some steps you might take to figure this out:

1)  Be conservative.  It is better to set the memory too low than too high.  Setting the value
too high can cause thrashing which slows down all programs.

2)  Start with how much memory is installed in your machine.  Allow a reasonable amount of memory
for the OS and whatever background tasks you run (say 0.5 to 2.0GB).  This represents the maximum
value you should use.  The program won't let you enter more than 90% of installed memory.

3)  Assuming you run your machine 24 hours a day, what hours of the day do you not use your computer?
Make these your nighttime hours and let the program use a lot of memory during these hours.  But
reduce this value if you also run batch jobs at night.

4)  Factor in the information below about minimum, reasonable, and desirable memory amounts for some
sample exponents.  If you choose a value below the minimum, that is OK.  The program will simply skip
stage 2 of P-1 factoring.

Exponent    Minimum        Reasonable    Desirable
--------    -------        ----------    ---------
100000000     0.2GB          0.7GB         1.1GB
333000000     0.7GB          2.1GB         3.5GB

For example, my machine is a dual-processor with 8GB of memory.  I guess Windows and the programs I
normally use can survive on 2GB of memory.  Thus, I set memory to 6.0GB.  This is my nighttime setting.
During the day, I run more programs, so I set memory to 1.5GB.  I can always stop prime95 if it is
doing stage 2 P-1 factoring and I suspect memory is thrashing.  More casual users might want to set the
daytime memory to 0.5GB so they never have to worry about prime95 impacting system performance.

2020-10-24, 03:48   #33
LaurV
Romulan Interpreter

Jun 2011
Thailand

8,963 Posts

Quote:
 Originally Posted by kriesel Go bigger if it won't get in the way of other things. And make day and night values the same to avoid restarts of stage 2 when the limits change with the time of day.
+1.

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