On Mon, 2006-12-11 at 20:15 -0600, Mike McCarty wrote: > Ed Greshko wrote: > > Mike Chalmers wrote: > > > > > >>I like Linux, alot. I mean alot. I like what it stands for (besides > >>the corporations). But my CPU has never overheated. I am pretty sure > >>that it is not my hardware. It could be a bug in Linux. The kernel > >>could be be sending incorrect frequencies to the hardware or something > >>like that. > > > > > > Hummmm.... Something like that happened to me years ago... Let me think. > > Oh, right..... > > [snip] > > It is a well-known fact that faulty software can overheat CPUs. [snip] I do believe that I can cause some processors to overheat, however, that software would not do anything useful. Once you start accessing memory, dealing with page faults and taking interrupts in the "real" environment that type of cycle intensive processing sort of goes out the window. Yes, processors are heat sensitive, and can fail due to heat, but the new coolers are very good, and the testing process ensures that the weak ones probably don't make it into the field. Believe me when I say the tests, which bypass many of the protections built in, stress the processors quite heavily, I do know what I am talking about. A modern processor can sustain a hundred amps or so of instantaneous current, which is made up by the multiple bypassing, board construction, path design and modern power supply design. In the test environment, they are not as fully cooled and protected as they are in your PC, so if they fail, that is where and when. You can check out some of the board designs on Teradyne's public materials (you don't get details, but you can see the complexity of connecting to over 1000 pins via a zero insertion force socket that must operate thousands of times reliably in a factory floor. The GIMP testing program I would suspect verifies such things as look ahead, que length call/return overhead and so forth to give a good "frames per second presentation" vs a temperature test of the processor. Flops (floating point operations per second) is the processing number important to graphics processing, and the hardware design will determine such things as how to best optimize the algorithms for best performance. That is one aspect of real time benchmarking. I can write the same 3 level nested loop at least 9 different ways. Some ways are most efficient on AMD systems, some are better on intel, and some fit power pc better. It depends on lots of things outside the processor as well. Memory speed, cache size and clock frequency to name some of the better known ones. As to the statement that faulty software could cause it, perhaps, but it would be a real fluke, because as I said lots of things get in the way in a real normal system. Such a software bug would have to disable lots of hardware besides the processor to create that kind of havoc. Maybe I should write a book.... Regards, Les H
