Re: Testing RAM from userspace / question about memmap= arguments

[Pavel Machek <pavel@ucw.cz>]

On Sun 2007-12-23 18:05:59, David Newall wrote:
> Pavel Machek wrote:
>> On Sun 2007-12-23 07:06:58, David Newall wrote:
>>   
>>> It's kind of hard to run anything over SSH if it has to be run before 
>>> userspace is up.  But the kernel can collect results from a modified 
>>> memtest, after it chains back.
>>>     
>>
>> memtest can be ran from userspace, that's the point.
>>   
>
> I'm not sure I believe that.  You need to tinker with hardware tables 
> before you know what physical RAM is being used.  Sequential virtual

No, I can just use /dev/mem. (After passing mem=XXX exactmap to kernel
so that I know what I may play with).

>> Yes, that's what CPU microcode update is for. And I want to test my
>> RAM with up-to-date microcode.
>>   
>
> Don't microcode updates fix CPU bugs?  That's not fixing faulty RAM.

L1/L2 cache is part of memory subsystem.

> I suppose a CPU retains microcode updates, once loaded, until power-down or 
> some hard reboot that you surely can avoid.  If it does happen that
> you

If CPU retains microcode after reset, then you are right. I'm not
sure.
								Pavel
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