Re: Corruption Stats: Suggested Blacklist from the data

MOLNAR Ingo (mingo@chiara.csoma.elte.hu)
Thu, 30 Jul 1998 00:52:22 +0200 (CEST)


On Wed, 29 Jul 1998, Alan Cox wrote:

> Also I have an Ingo project - Ingo can you write a PCI bus speed measurer
> for the kernel - is it possible.

i think it's quite hard to find a generic method. On SMP it's easy, the
PCI bus speed is half of the APIC bus speed. (and we already calculate the
APIC bus clock speed)

on UP it's hard as we do not have an APIC (or enabled). We might be able
to measure the memory bus speed, but the multiplier between the PCI bus
and the memory bus is not necessarily 2.0. (think 100MHz Super7
motherboards, BX chipsets, etc.)

so the only thing left is to poke the PCI bus directly and measure that
speed. Unfortunately i have found no way to create some reliable
nonintrusive transaction on the PCI bus that can be measured. maybe
reading the config space takes some constant number of PCI cycles?

> Quantum Fireball ST (2 times, both with other drives) on the cable also seeing
> problems. Other drive was 'unknown' in one case '1.6 gig WD' in the other

'ST' ? isnt that an SCSI drive? You mean Fireball xxxxAT?

-- mingo

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