Re: Overheating Pandas

Folks, I had my final round of tests and I can say that there is no final conclusion on why they fail, but they do failed under every scenario I could try them on. I've tested 3 identical boards (Panda-ES RevB2) with 5 different power supplies. Even at 920MHz, with decent power supplies (high-qua

Re: Overheating Pandas

On 8 July 2013 14:48, Siarhei Siamashka wrote: > And naturally, any PSU rated for just something like 1A will not work > right, that's a common sense. The modern multi-core ARM boards can > easily consume a lot more than this under load. But at least 2.5A or > 3A should be sufficient if you don't

Re: Overheating Pandas

On Sun, 7 Jul 2013 19:00:47 -0300 Christian Robottom Reis wrote: > On Sat, Jul 06, 2013 at 09:39:13AM +0100, Renato Golin wrote: > > On 5 July 2013 08:56, Renato Golin wrote: > > > > > Yesterday I turned one of the boards back to 1.2GHz (3pm), and it died > > > during the night (2am). The 920MH

Re: Overheating Pandas

On Sat, Jul 06, 2013 at 09:39:13AM +0100, Renato Golin wrote: > On 5 July 2013 08:56, Renato Golin wrote: > > > Yesterday I turned one of the boards back to 1.2GHz (3pm), and it died > > during the night (2am). The 920MHz is still working. The room temperature > > didn't go over 26C (the thermome

Re: Overheating Pandas

On 5 July 2013 08:56, Renato Golin wrote: > Yesterday I turned one of the boards back to 1.2GHz (3pm), and it died > during the night (2am). The 920MHz is still working. The room temperature > didn't go over 26C (the thermometer is by the boards). > Status update: One of the boards failed at 92

Re: Overheating Pandas

On 4 July 2013 12:27, Renato Golin wrote: > On 3 July 2013 18:33, Richard Earnshaw wrote: > >> keep lowering the clock limit (.../cpufreq/scaling_max_freq) until you >> get stability. If you don't, then it isn't a heating problem. >> > > It might be a bit too soon, but I just got a few 7h build

Re: Overheating Pandas

On 4 July 2013 19:15, Mans Rullgard wrote: > Chips intended for compute clusters will no doubt be possible to cool > sufficiently to run at full speed all the time. Designing chips for > different > markets involves different sets of tradeoffs, and you're seeing the result > of that. > Yes, thi

Re: Overheating Pandas

On 4 July 2013 18:10, Renato Golin wrote: > On 4 July 2013 17:13, Siarhei Siamashka wrote: >> >> By the way, power consumption is not constant and heavily depends on >> what the CPU is actually doing. And 100% CPU load in one application >> does not mean that it would consume the same amount of p

Re: Overheating Pandas

On 4 July 2013 17:34, Siarhei Siamashka wrote: > For getting reproducible benchmark results, you just need to ensure > that thermal throttling never kicks in. If the kernel is compiled > with cpufreq stats enabled, you can compare these stats before/after > your benchmark to ensure that it spent

Re: Overheating Pandas

On 4 July 2013 17:13, Siarhei Siamashka wrote: > By the way, power consumption is not constant and heavily depends on > what the CPU is actually doing. And 100% CPU load in one application > does not mean that it would consume the same amount of power as 100% > CPU load in another application.

Re: Overheating Pandas

On Wed, 3 Jul 2013 16:48:51 +0100 Renato Golin wrote: > But more to the point, I don't want to be scaled down when hot, I want it > never to get hot in the first place, so I can run at full 1.2GHz, 24 / 7. > If the scheduler reduces the frequency to decrease the temperature, I'll be > testing mor

Re: Overheating Pandas

On Wed, 3 Jul 2013 15:59:47 +0100 Mans Rullgard wrote: > On 3 July 2013 14:13, Renato Golin wrote: > > Hi Folks, > > > > I'm running two buildbots here at home and am getting consistent failures > > from the Pandas because of overheating. I've set up a monitor that will tell > > me the current C

Re: Overheating Pandas

On 3 July 2013 18:33, Richard Earnshaw wrote: > keep lowering the clock limit (.../cpufreq/scaling_max_freq) until you get > stability. If you don't, then it isn't a heating problem. > It might be a bit too soon, but I just got a few 7h builds out of the boards at 920MHz without a single glitch

Re: Overheating Pandas

On 3 July 2013 23:01, Will Newton wrote: > It may also be worth examining your power supplies and see if they are > providing enough current to run the chip this hot reliably. A bench > supply could eliminate this possibility conclusively. > They're cheap... *very* cheap... They're not the ones

Re: Overheating Pandas

On 3 July 2013 14:13, Renato Golin wrote: > Hi Folks, > > I'm running two buildbots here at home and am getting consistent failures > from the Pandas because of overheating. I've set up a monitor that will tell > me the current CPU temperature and the allowed maximum, and when the bot > passes 90%

Re: Overheating Pandas

On 3 July 2013 18:33, Richard Earnshaw wrote: > On 03/07/13 17:41, Renato Golin wrote: >> >> On 3 July 2013 17:22, Mans Rullgard > > wrote: >> >> I repeat, the 4460 will run at 1.2GHz indefinitely without thermal >> management. >> >> >> My mistake, I said 1

Re: Overheating Pandas

On 3 July 2013 18:33, Richard Earnshaw wrote: > Chips expected to dissipate large amounts of power normally have a metal > pad on the package so that a heat sink with thermal grease will make a good > thermal contact. > This is a really good point. The heat-sink do get really hot, but it's not t

Re: Overheating Pandas

On 3 July 2013 18:08, Mans Rullgard wrote: > 4430 max frequency is 1.0GHz unless I'm mistaken. Either way, try > reducing your clock to 1.0GHz and see what happens. > Yes, I meant 4430 and 4460 at their natural high frequencies. $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_freq

Re: Overheating Pandas

On 03/07/13 17:41, Renato Golin wrote: On 3 July 2013 17:22, Mans Rullgard mailto:mans.rullg...@linaro.org>> wrote: I repeat, the 4460 will run at 1.2GHz indefinitely without thermal management. My mistake, I said 1.3GHz when it was actually 1.2GHz. So, at 1.2GHz, it freezes every few

Re: Overheating Pandas

On 3 July 2013 17:41, Renato Golin wrote: > On 3 July 2013 17:22, Mans Rullgard wrote: >> >> I repeat, the 4460 will run at 1.2GHz indefinitely without thermal >> management. > > > My mistake, I said 1.3GHz when it was actually 1.2GHz. So, at 1.2GHz, it > freezes every few hours on full load on b

Re: Overheating Pandas

On 3 July 2013 17:22, Mans Rullgard wrote: > I repeat, the 4460 will run at 1.2GHz indefinitely without thermal > management. > My mistake, I said 1.3GHz when it was actually 1.2GHz. So, at 1.2GHz, it freezes every few hours on full load on both 4430 and 4460. linaro@linaro-panda-01:~$ cat /sys

Re: Overheating Pandas

On 3 July 2013 16:48, Renato Golin wrote: > On 3 July 2013 15:59, Mans Rullgard wrote: >> >> An OMAP4460 will run at 1.2GHz indefinitely without overheating in >> reasonable ambient temperature. >> >> If you don't have thermal management in the kernel you're running, you >> need to clamp the cloc

Re: Overheating Pandas

On 3 July 2013 15:59, Mans Rullgard wrote: > Modern silicon processes are much more power-efficient than those of the > 90s. > For example, an old ~500MHz Alpha machine I have readily consumes 90W even > when idle. A quad-core Intel i7 typically has a TDP of 130W at full load. > That's orders of

Re: Overheating Pandas

On 3 July 2013 14:13, Renato Golin wrote: > Hi Folks, > > I'm running two buildbots here at home and am getting consistent failures > from the Pandas because of overheating. I've set up a monitor that will tell > me the current CPU temperature and the allowed maximum, and when the bot > passes 90%