Messages in this thread | ![/](/images/icornerl.gif) | | From | "Daniel J Blueman" <> | Subject | Re: DRAM thermal throttling by 440BX chipset | Date | Sat, 20 Nov 1999 16:44:59 -0000 |
| |
I was reading about DRAM throttling a while ago from the i440BX chipset datasheet, but I couldn't understand why it is implemented, on the basis the added complexity monitoring memory-bus activity, etc surely wouldn't outweigh the benefit(s) it brings (DIMMs / chipset chips running a bit cooler?).
I know that on my Abit BX-based BP6, the (north-bridge) memory/bus controller chip gets quite hot due to my setup. Hmmm....in the LX and previous server chipsets, this kind of feature wouldn't have been implemented, and with the recent injection of good-value SMP motherboards, this would explain why this recent issue has appeared.
In the Intel docs, it states that *system* throttling is used to reduce the host clock (-> processor, host, memory, AGP and PCI bus clock, since they're syncronous with the host clock). It also mentions thermal throttling, when engaged start toggling the host-bus clock generator with the STPCLK# (pause-clock?) signal and ZZ signal (idle/sleep?) with a period of 244us and a programmable duty cycle. This simulates reducing the clock frequency, reducing thermal output, power consumption, etc.
As far as I understand, this only comes into action when the system is in some power-saving mode though. Try turning off all ACPI and APM stuff in the (latest) BIOS. I get the occasional APIC rouge interrupt or whatever.
Off-topic: Does anyone know what settings are optimal for PCI write-combining and PCI passive-release (obvious latency vs bandwidth vs service issues here). I assume both set to on is best, for less latency at the expense of a bit of bandwidth (from overheads, etc).
i440BX overview at: http://developer.intel.com/design/intarch/techinfo/440bx/index.htm
register list at: http://developer.intel.com/design/intarch/techinfo/440bx/HostPCI.htm
information about power managment, etc: http://developer.intel.com/design/intarch/techinfo/440bx/pwrclock.htm
Cheers, Dan
System: Abit BP6 w/ dual iCeleron 366's o/c to 561. 128MB memory, 3dfx Voodoo 3. Linux. __________________________ Daniel J Blueman Undergraduate - BSc Computing Science UMIST university - Manchester Direct line: 0161 933 3569 Mobile: 07775 583766 Email: daniel.j.blueman@stud.umist.ac.uk SMS: daniel.j.blueman@sms.genie.co.uk
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| ![\](/images/icornerr.gif) |