Message boards :
Number crunching :
Progress Nonlinearity
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Author | Message |
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Rich Burgan, WC8J Send message Joined: 19 May 99 Posts: 5 Credit: 109,718 RAC: 0 |
The 'progress' field under the 'work' tab on the BOINC GUI expresses a % complete value. This is very nonlinear. Essentially it goes up to 42% in the first 5 minutes of computation and then rises to 100% at completion. 100...................................+ .80.......................+ .60...........+ .40.+ .20+ ..0+ ..0 5 -elapsed time minutes- 145 |
Bruno Moretti IK2WQA Send message Joined: 15 May 99 Posts: 284 Credit: 49,167 RAC: 0 |
Yes, Rich WC8J. It's a know secondary bug and not important. --... ...-- Clear skies from SETI ITALIA [/url] Cicognola Astronomical Observatory & IK2WQA Radio Station SETI League IARA GAT IDA CieloBuio IARU ARI |
Petit Soleil Send message Joined: 17 Feb 03 Posts: 1497 Credit: 70,934 RAC: 0 |
CPU temp shows that nonlinear processing. Temp is slowly decreasing as the process goes. I have noticed 68 at start and 62 Deg C at the end. So the CPU "works harder" at let say 10% then 90% progress. Dah dah di di dit di di di da dah dah Marc |
Rich Burgan, WC8J Send message Joined: 19 May 99 Posts: 5 Credit: 109,718 RAC: 0 |
For the first 43% the fan on my laptop runs slow then speeds up (max?) for the rest of the time. Is the temperature going down because the fan is running faster? --... ...-- |
Petit Soleil Send message Joined: 17 Feb 03 Posts: 1497 Credit: 70,934 RAC: 0 |
Actualy no. The fan on my laptop is running at same speed between 60 - 70 Deg. I have lift up the laptop using home made stand with cooling fan underneth providing cool air to the bottom of the laptop. Before that it was reaching 72 and I could ear the fan speeding up at 70. I can clearly see that the CPU works harder when starting a new WU. I have watched closely MBM during WU transition. At 99% cmpletion the temp is 62 and it rise at 68 when it start crunching the next WU. As I am writing this a WU is at 99.6% completion and temp is at 61. It will then jump to 62, 63, 64 up to 68 and then it will slowly decrease back to 61,62 with the fan running at same speed. I monitor the fan with MBM and by the sound. So to me the WU are more power demanding at the beginning. |
Rich Burgan, WC8J Send message Joined: 19 May 99 Posts: 5 Credit: 109,718 RAC: 0 |
Your experience with CPU temperature is interesting. I will have to watch mine more closely. Maybe I have mis-interpreted what I'm seeing. Cheers! |
Petit Soleil Send message Joined: 17 Feb 03 Posts: 1497 Credit: 70,934 RAC: 0 |
@Rich Keep me informed of your dicoveries. I have made a close watch of a complete WU process and took temp snapshots. Completion time is 5 hours 0 -10% 62-63-64-65-66-67 deg.C 10-40% 68 40-50% 67-66 50-70% 66-65 70-90% 64-63 90-100% 62 END OF WU STARTING NEW 0 -10% 62-63-64-65-66-67 deg.C etc. If the CPU work load was the same thruout the process the temp would not change at the beginning of a new WU and the temp would stay at 62. Marc |
Bruno Moretti IK2WQA Send message Joined: 15 May 99 Posts: 284 Credit: 49,167 RAC: 0 |
With BOINC running 24/24 & 7/7 my temp is always 52-54 deg Celsius on all my machines, since Dec 2002. In about 25 deg Celsius air conditioning site. ;-) --... ...-- Clear skies from SETI ITALIA [/url] Cicognola Astronomical Observatory & IK2WQA Radio Station SETI League IARA GAT IDA CieloBuio IARU ARI |
Petit Soleil Send message Joined: 17 Feb 03 Posts: 1497 Credit: 70,934 RAC: 0 |
> With BOINC running 24/24 & 7/7 > my temp is always 52-54 deg Celsius > on all my machines, > since Dec 2002. > > In about 25 deg Celsius air conditionig site. ;-) > Thanks Bruno for the info. It's weird. Maybe specific to my machine ? some kind of power management ? Or it could be that my fan decrease speed during the small time lap of WU transition witch makes the temp uncreasing at around 68 deg Celsius untill fan speed increase. I have to check again on that maybe MBM is not correctly setup and fan reading is wrong and / or I have earing problems... I'll have a deeper look. Thanks Marc |
Chelski Send message Joined: 3 Jan 00 Posts: 121 Credit: 8,979,050 RAC: 0 |
I see the same thing on both my machines. Don't think it is temp though. Maybe because the way the progress is calculated i.e. % steps completed are linear but the computation to process the steps may varies from short to long as we crunch? |
Christopher Hauber Send message Joined: 10 Feb 01 Posts: 196 Credit: 71,611 RAC: 0 |
Until you said this was on a laptop this didn't make much sense to me. Regardless of where you are in processing the workunit, it processes at 100% usage and unless there is more to it than I realize, that *should* indicates that the processor is using just as much power at as at any other stage which would make produce the same amount of heat. I can't see it making a significant difference in temperature at all. Except that most if not all laptops have some sort of variable speed fan to save power. So when it gets hot, it will turn the fan on as high as it needs to to cool the processor. When it cools it to a certain point, it lowers the fan speed basically until it maintains the temperature within a certain range. That is really the only explanation that I can see explaining it based on my experience with laptops. Chris > > Thanks Bruno for the info. > > It's weird. Maybe specific to my machine ? > some kind of power management ? > Or it could be that my fan decrease speed during the > small time lap of WU transition witch makes the > temp uncreasing at around 68 deg Celsius untill fan > speed increase. I have to check again on that maybe > MBM is not correctly setup and fan reading is wrong > and / or I have earing problems... > I'll have a deeper look. > > Thanks > Marc > > |
Petit Soleil Send message Joined: 17 Feb 03 Posts: 1497 Credit: 70,934 RAC: 0 |
That is really the only > explanation that I can see explaining it based on my experience with laptops. > > Chris > > Thanks Chris I agree with you. I have tested the fan and it shows same speed in the 60-68 deg celsius range. I first thaugh it was 60-70 Deg. Please note that my laptop is always pluged in and it's not affected by any power saver unless I run on the batery. I still don't understand why it goes from 62 to 68 when it start processing a new WU. I have watched the temp in the system tray during the last WU transition. Actually I can tell when it starts a new one even when boinc is minimized. Progress was at 99% and temp was 62 when I minimized boinc and kept an eye on sys tray temp reading. It started to rise slowly from 62 to 68 and I then knew it was starting to crunch a new WU. Grrrrrrr!!! I should have think of that before ! There could be one good explanation. The interval between MBM reading is about 5 seconds. If the transition between WU keeps the processor idle long enough the temp might go under 60 but I don't see it. the fan speed would decrease and for some reason the sensor system don't kicks in at 60 but at 68. This could be a good explanation only if there is a processing "pause" between WU transition. I have to check that. The only way to be 100% sure would be to set the fan at a fixed RPM and check the temp during transition. I'm not sure if I can do it with my machine. I will check the bios. Marc |
Pete49 Send message Joined: 28 Jul 04 Posts: 64 Credit: 250,376 RAC: 0 |
Another possible explanation could be the algorithm the SETI program is using. Even though a processor is being externally utilized 100%, not all of the internal registers, caches, etc are being used. As floating point calculations increase in complexity, the internal usage of the processor increases which would result in an increase in temp. |
ric Send message Joined: 16 Jun 03 Posts: 482 Credit: 666,047 RAC: 0 |
When a cpu is getting hot while processing (a wu), after stopping the high usage, it will take much more time as 5 seconds to go realy down the temp. please also include this: many motherboard offers different location, where the temp sensor is placed, some are on the MB, just near the cpu, some more away. Your monitoring software, does it allow to select what sensor is used for the mesurement? Don't ask me in details, but only newer CPUs (amd and intel) have a sensor build in AND can deliver the temp status. This can produce a other value of temp than effectively is. and.. some time ago, an "important" pc-magazine made some laboratory test concerning temp mesurement, they mesured differences till 8% from the effective values of temp. Same in the u min of the air cooling units wishing cool cpus ric |
Petit Soleil Send message Joined: 17 Feb 03 Posts: 1497 Credit: 70,934 RAC: 0 |
@Pete49 That was my feeling too when I wrote "more power demanding" at the begining of a WU. I have the feeling that the calculations are more intensive in the first 40% of the WU. @RichiMeister I know my CPU would not cool completely in 5 seconds but it might be enough to cool from 62 to 60. the fan speed is decreasing at 60 so if there is a long enough time lap between two WU that could have been an expanation. My machine is a 2 years old Compaq Presario 2800 P4M 1.4 GHz Its got one sensor on the cooling block and another on the CPU. I monitor both with MBM. ---- It could well be both reasons. Algorith and fan speed. One thing for shure the temp goes from 62 to 68 in about 4 minutes when starting a new WU. Thanks to all. My quest for the reasons continue Best regards Marc |
Petit Soleil Send message Joined: 17 Feb 03 Posts: 1497 Credit: 70,934 RAC: 0 |
OK I am now 100% sure that those non linear WU has a higher usage of the processor ressources at the begining of the process. The first pic is a screen capture showing a boinc SETI WU at 99% progress. Note the MBM temperature in the system tray. The temperature reading from left to right are BLOCK and CPU. 47 and 62 deg celsius. The second pic shows a second screen capture taken 9 minutes later. The new WU progress is 40% and the temperatures are 51 and 69 I have just finished crunching a normal (linear progress %) work unit and the temperature stayed at 65 deg. Celsius during complete process. There is no doubt in my mind that the temperatures reading reflects that those nonlinear progress WU are also non constant as for Processor usage. |
ric Send message Joined: 16 Jun 03 Posts: 482 Credit: 666,047 RAC: 0 |
ping "threat still alive?" |
Petit Soleil Send message Joined: 17 Feb 03 Posts: 1497 Credit: 70,934 RAC: 0 |
> ping "threat still alive?" > Which threat ? -.-. --.- -.. -..- . - .-.-. -.- --... ...-- |
ric Send message Joined: 16 Jun 03 Posts: 482 Credit: 666,047 RAC: 0 |
> > ping "threat still alive?" > > > Which threat ? > > > > -.-. --.- -.. -..- . - .-.-. -.- --... ...-- sorry, not threat, 2nd chance, thread (still learning english).. but it's to admit, I was able to copy 5 of 6 chars from the adress line, it's not to bad fo me. |
Masher1 Send message Joined: 24 Jun 01 Posts: 1 Credit: 454 RAC: 0 |
the W/U feed is not allways a stable linear thing sometimes the tele-scope is moving excessively {hence the 2 sec wu) or speeding up or slowing down {the non-linear wu} the data somtimes is less than optmial for the search these thing can all have the effect you see |
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