Index  | Recent Threads  | Unanswered Threads  | Who's Active  | Guidelines  | Search
 

Quick Go ยป
No member browsing this thread
Thread Status: Active
Total posts in this thread: 8
[ Jump to Last Post ]
Post new Thread
Author
Previous Thread This topic has been viewed 1535 times and has 7 replies Next Thread
Former Member
Cruncher
Joined: May 22, 2018
Post Count: 0
Status: Offline
Reply to this Post  Reply with Quote 
Is it normal to be processing two workunits at a time?

I have two "work units" being processed simultaneously and this would seem to be counterproductive to having all processor power working on only one unit. Is it normal to have two downloaded and being processed at a time?
[Oct 25, 2007 7:46:42 PM]   Link   Report threatening or abusive post: please login first  Go to top 
Former Member
Cruncher
Joined: May 22, 2018
Post Count: 0
Status: Offline
Reply to this Post  Reply with Quote 
Re: Is it normal to be processing two workunits at a time?

I have two "work units" being processed simultaneously and this would seem to be counterproductive to having all processor power working on only one unit. Is it normal to have two downloaded and being processed at a time?


Perfectly normal (and very productive) if you have a dual-core processor?
[Oct 25, 2007 7:48:04 PM]   Link   Report threatening or abusive post: please login first  Go to top 
jal2
Senior Cruncher
USA
Joined: Apr 28, 2007
Post Count: 422
Status: Offline
Project Badges:
Reply to this Post  Reply with Quote 
Re: Is it normal to be processing two workunits at a time?

However, it can be counter-productive if you are using simulated (hyper-threaded) processors. Ideally, the number of WU should not exceed the number of physical cores.
There are discussions elsewhere about multi-threading the WUs across multiple physical cores.
----------------------------------------
----------------------------------------
[Edit 1 times, last edit by jal2 at Oct 25, 2007 7:54:42 PM]
[Oct 25, 2007 7:53:18 PM]   Link   Report threatening or abusive post: please login first  Go to top 
Former Member
Cruncher
Joined: May 22, 2018
Post Count: 0
Status: Offline
Reply to this Post  Reply with Quote 
Re: Is it normal to be processing two workunits at a time?

Thanks for the quick responses. Obviously I am new to this. smile

Yes, I am using a dual-core PC.
[Oct 25, 2007 8:00:09 PM]   Link   Report threatening or abusive post: please login first  Go to top 
Former Member
Cruncher
Joined: May 22, 2018
Post Count: 0
Status: Offline
Reply to this Post  Reply with Quote 
Re: Is it normal to be processing two workunits at a time?

However, it can be counter-productive if you are using simulated (hyper-threaded) processors. Ideally, the number of WU should not exceed the number of physical cores.
There are discussions elsewhere about multi-threading the WUs across multiple physical cores.


Can you elaborate? I'm running on a hyperthreaded pentium IV single-core processor and I'd like it if I could just do 1 at a time instead of 2.
[Nov 20, 2007 12:48:46 AM]   Link   Report threatening or abusive post: please login first  Go to top 
Former Member
Cruncher
Joined: May 22, 2018
Post Count: 0
Status: Offline
Reply to this Post  Reply with Quote 
Re: Is it normal to be processing two workunits at a time?

Hello Blarrrg,
Good idea! The Pentium 4 will run 2 threads simultaneously unless you specify only 1 thread. 2 work units take twice as much memory but run only slightly faster than a single thread. Go to My Grid - Device Manager and click on your device profile. This will bring up the device preferences page. By default, it is set to run up to 4 threads per processor. Set it to run only 1 thread per processor, then SAVE the new profile. After your BOINC client downloads the new profile, it will only run one work unit at a time. This is better than 2 unless you have lots of RAM and do not use your computer much.

Lawrence
[Nov 20, 2007 1:16:19 AM]   Link   Report threatening or abusive post: please login first  Go to top 
crooks_uk
Veteran Cruncher
England
Joined: Nov 25, 2004
Post Count: 1011
Status: Offline
Project Badges:
Reply to this Post  Reply with Quote 
Re: Is it normal to be processing two workunits at a time?

Hello Blarrrg,
Good idea! The Pentium 4 will run 2 threads simultaneously unless you specify only 1 thread. 2 work units take twice as much memory but run only slightly faster than a single thread. Go to My Grid - Device Manager and click on your device profile. This will bring up the device preferences page. By default, it is set to run up to 4 threads per processor. Set it to run only 1 thread per processor, then SAVE the new profile. After your BOINC client downloads the new profile, it will only run one work unit at a time. This is better than 2 unless you have lots of RAM and do not use your computer much.

Lawrence


I know that this has been discussed in detail in the past. But, I have ran all versions on the BIONC agent on 3 x P4 HT machines, running two units at a time, with all machines having 512MB RAM (not a lot these days) and have never had any problems.
----------------------------------------
[Nov 20, 2007 12:28:43 PM]   Link   Report threatening or abusive post: please login first  Go to top 
Sekerob
Ace Cruncher
Joined: Jul 24, 2005
Post Count: 20043
Status: Offline
Reply to this Post  Reply with Quote 
Re: Is it normal to be processing two workunits at a time?

One process runs in the real core. The other is virtual and uses the small gaps. The process manager will show each using 50% i suppose, but in reality the 2 processes are getting half and a few percentage points more from the little gaps that HT is utilizing, so in the end your 2 jobs finish in near twice the wall-clock time versus. Depending on RAM it could even take longer than twice on the wallclock because of e.g. swapping.

Whilst it may work for the individual case, the recommendation is to just allow 1 CPU in the profile *for HT* CPU's. If you try, you will discover that a job finishes in half the wallclock time.

Added Rumour has it that Intel is going to re-introduce HT in their dual cores.... they dropped it apparently due design complications building the original duo's.
----------------------------------------
WCG Global & Research > Make Proposal Help: Start Here!
Please help to make the Forums an enjoyable experience for All!
----------------------------------------
[Edit 1 times, last edit by Sekerob at Nov 20, 2007 12:43:31 PM]
[Nov 20, 2007 12:40:18 PM]   Link   Report threatening or abusive post: please login first  Go to top 
[ Jump to Last Post ]
Post new Thread