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Double Processor HT
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Author | Message |
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Send message Joined: 5 Aug 04 Posts: 171 Credit: 10,364,481 RAC: 21,716 |
Hi, my box has an Intel P4 with Hyperthreading. If I allow in my profile \"use 2 Prozessors\", will the client run ONE simulation with both prozessors or will the client run 2 different simulations ? |
Send message Joined: 5 Aug 04 Posts: 390 Credit: 2,475,242 RAC: 0 |
Hi Yeti, there is no way (so far) to use multiple CPUs on a single model -> each CPU is simulating different model. You can get some +15% on P4 HT but keep in mind that it need another 50-60MB of RAM, HD space etc. You may also find interesting running single BOINC model and keep your 'classic' CPDN/Win running another; assuming you are on Win platform. |
Send message Joined: 5 Aug 04 Posts: 907 Credit: 299,864 RAC: 0 |
Hi, as Honza says it will be one workunit per CPU (I believe all BOINC projects behave this way, not just CPDN). |
Send message Joined: 5 Aug 04 Posts: 171 Credit: 10,364,481 RAC: 21,716 |
Yeah, as you prognosted: My workstation is crunching two modells now ... Thanks four your help :-) |
Send message Joined: 14 Aug 04 Posts: 37 Credit: 276,676 RAC: 0 |
There was a lot of debate (on the BOINC beta board and elsewhere) about the > 1 cpu/2 cpu/ HT The conclusion that I came to was that there was little benefit from running HT so I switched it off on my intel P4 3.06 PC and set my Prefs to 1 cpu for this PC. The situation may be different for AMD cpu's. K. |
Send message Joined: 5 Aug 04 Posts: 907 Credit: 299,864 RAC: 0 |
> The situation may be different for AMD cpu's. actually my experience is that HT is pretty good on these climate models -- you lose a little bit "seconds per timestep" but you get two models done in a little bit extra time (so your "model throughput" is almost halved, i.e. you effectively are doing a model every 10 days instead of 18 days or whatever) |
Send message Joined: 8 Aug 04 Posts: 10 Credit: 33,167 RAC: 0 |
> There was a lot of debate (on the BOINC beta board and elsewhere) about the > > 1 cpu/2 cpu/ HT > > The conclusion that I came to was that there was little benefit from running > HT so I switched it off on my intel P4 3.06 PC and set my Prefs to 1 cpu for > this PC. > > The situation may be different for AMD cpu's. > > K. > > > I'm running a P4 3.0E 512Mb DDR800 PC3200 with HT and am getting; Model 1, 3.01 s/TS Model 2, 3.12 s/TS It should take me 28 cpu days to complete 2 models, from looking at other P4 3.0E cpu's with HT off it should take on average 33 cpu days to complete 2 models. Thats 5 days faster for 2 models but thats guessing at this point and we will have to wait and see. |
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