Questions and Answers : Windows : Quad and dual core set-up
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Send message Joined: 11 Jun 05 Posts: 67 Credit: 1,222,916 RAC: 0 |
Hi all, Just a general question for BOINC apps. Currently, I have two dual-core machines (one isn\'t set-up though yet!!) Now, if I upgrade one machine to quad-core, leaving the other dual-core intact, how do I set-up my BOINC Manager preferences? I have a couple of projects which run on both machines (CPDN for example). Should I just set my home prefs to be \"use 4 processors\" max, catering for the quad-core, hoping the dual-core machine won\'t try to start 4 Models!!! Looking to the future - Intel Nehalem. Quad-core processors, but with the equivalent of Hyper-Threading re-invented.....so, 8 effective threads/models can be run at once. What then in the Boinc Preferences???? Best regards, Neil. |
Send message Joined: 5 Sep 04 Posts: 7629 Credit: 24,240,330 RAC: 0 |
Use different Venues for the different machines. That way they can be set for different prefs. What then in the Boinc Preferences???? They will say %, not Number, because by then you\'ll be using BOINC version 6. :) |
Send message Joined: 9 Jan 07 Posts: 467 Credit: 14,549,176 RAC: 317 |
Neil, There are a number of ways to make PCs behave differently: 1. Set the \'host location\' to different values for each PC (home, work and school are allowed). The location can be changed at the bottom of the computer summary page; then create a new set of \'computing preferences\' in your account. The preferences will be applied on the next update. 2. Use the local preferences to override the default or location-specific settings (BOINC Manager | Advanced | Preferences). In any event, a PC won\'t attempt to start more models than it has processors. Hyperthreaded processors are, however, considered by the operating system as real processors: this may not be what you want, and you\'ll need to set the preferences to get the right effect when you get your quad + HT processor (there are Xeons that already work like that). Iain [Edit: Les got there first. Using \'% of processors\' instead of \'# of processors\' might be a bit of a pain with HT. It may also create pressure to increase the limited number of locations, or force people to use local preferences - which might cause some bafflement when problems arise.] |
Send message Joined: 5 Sep 04 Posts: 7629 Credit: 24,240,330 RAC: 0 |
One thought that occurred to me after I posted: If you have an octo-core, and want to leave one processor free for day-to-day use, you need to work out what percentage 7/8 is. :( |
Send message Joined: 29 Sep 04 Posts: 2363 Credit: 14,611,758 RAC: 0 |
I don\'t think the University College of Berkeley realises that not everybody understood percentages and fractions at school. I hope they go back to letting us just count our cores on our fingers (plus toes for the better-endowed among us). Cpdn news |
Send message Joined: 5 Sep 04 Posts: 7629 Credit: 24,240,330 RAC: 0 |
The problem, apparently, is that the \"unit of data\" that was used for the \"number of processors\" in the BOINC code has a maximum value of decimal 16, which would mean that \'they\' used half a byte to store the value. A bit (no pun intended), like the original IBM pc design, which allowed for a maximum of 640Kbytes of memory. After all, who could possibly need more than this? edit I just tried it with a calculator, and 7/8 is .875 So, just reverse the numbers, and put a decimal point in front of them. Just as well that I\'m planning to give the HT processor a miss, and stay with \'real\' quad cores. |
Send message Joined: 11 Jun 05 Posts: 67 Credit: 1,222,916 RAC: 0 |
So can you confirm that 3/4 = 0.43 in decimal terms??? |
Send message Joined: 31 Dec 07 Posts: 1152 Credit: 22,363,583 RAC: 5,022 |
Guys, I was terrible at math, but, even I know that to turn a decimal fraction into a percent you move the decimal point 2 places to the right and add a percent sign. .875 is 87.5%. |
Send message Joined: 5 Sep 04 Posts: 7629 Credit: 24,240,330 RAC: 0 |
My calculator says that 3/4 = 0.75 As for 7/8 is .875, it is. I was just trying to work out an easy way to remember it. A bit like the latest port number for BOINC is PI. And to turn .875 into percent, you do indeed move the decimal point to the right. But it turns out that it doesn\'t matter anyway, because someone posted, (here), that the required figure is 88% to give 7 processors on an octo-core. |
Send message Joined: 29 Sep 04 Posts: 2363 Credit: 14,611,758 RAC: 0 |
3/4 is 0.75%. When Les said \'I just tried it with a calculator, and 7/8 is .875. So just reverse the numbers, and put a decimal point in front of them.\' I think it was just a fluke that works for that particular fraction & percentage. 1/8 doesn\'t work out as 0.81% and 2/3 isn\'t 0.32%. Unless Les starts a new Australian academic discipline called Bayliss Outback Inconsistent Neuro-Calculation. Cpdn news |
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