Re: [Xen-devel] issues getting more than 16M ram to be used without oopsing. 1.2 and 1.3-unstable

["Brian Wolfe" <brianw@xxxxxxxxxxxx>]

Would a decchip tulip card be a good choice for xen?  Digital Equipment
Corporation DECchip 21140 [FasterNet] (rev 22).

I also have a server class Intel ether card (not certain of the version,
have to drop it in a system) that I can try on the server.

btw, I just noticed that I misspelled your name on my files. ;-P Sorry
bout that. :)

Thank you for the amazingly fast response times to my issues. This is
moving faster than suport that I have gotten from IBM for it's AIX RS6000
servers!


I do have a fairly large array of various low end network cards. I'll set
aside some time to test what I can on the spare parts that I have. If I
can manage more spare time I cna try to learn what needs to be done with
the network stuff to make other cards from linux 2.4 work with Xen.

Looks like i Have a bit of learning to do... :) though it should be fun to
try.

-- 
Brian Wolfe           | Phone 1-(214)-764-1204
President,            | Email  brianw@xxxxxxxxxxxx
TerraBox.com Inc.     |


pub  1024D/73C5A2DF 2003-03-18 Brian Wolfe <brianw@xxxxxxxxxxxx>
     Key fingerprint = 050E 5E3C CF65 4C1E A183  F48F E3E3 5B22 73C5 A2DF
sub  1024g/BB87A3DD 2003-03-18


Keir Fraser said:
>>
>> > Heh, I know what you mean on the VIA boards. I almost always have an
>> issue
>> > booting > 3 month old kernels on them. 8-P I spose I could look at via
>> as
>> > a "enforced upgrade" system. ;)
>> >
>> > *nod* I'd tried the noacpi, ignorebiostables, etc. All of the usual
>> tricks
>> > on the xenolinux.gz kernel image as well to no avail pror to harassing
>> > yall. :) I think my friend Adam was feeling a bit abused as a Xen
>> suport
>> > route as well. *grin*
>> >
>> > Things are getting a LITTLE bit futher on the bootup. :) Any chance
>> the
>> > IDE , USB, and/or ethernet interfaces are doign something funky?
>>
>> Looks like the Ethernet interface might be doing bad things. Both
>> crashes are at the same point in its interrupt handler. I'm not sure
>> whether this is a cause or merely a symptom though.
>>
>> I'll take a look. Meanwhile, can you put a different card in that
>> machine? For example, we know that 3com 3c905's are good. 3c595 is a
>> relic. :-)
>
> Okay, I think I've found and fixed the problem. I've made pre-built
> images available at:
>  http://www.cl.cam.ac.uk/~kaf24/xen.gz
>  http://www.cl.cam.ac.uk/~kaf24/xenolinux.gz
>
> The problem is that the 3c595 is not using DMA, but is instead using
> PIO (polled I/O). This is doubly bad in Xen:
>  1. The main CPU is responsibel for transferring all data to/from slow
>  on-card memory.
>  2. Xen needs to temporarily map the buffer into its address space to
>  execute the transfer.
>
> It was the latter which was not being done -- Xen has a one-to-one
> mapping of onyl the first 40MB of physical memory. If the buffer
> location is any higher than that then we ended up copying received
> packets to a random location!
>
> So, if you're looking for decent performance then you want to get
> yourself a good network card -- eg. 3c905.
>
> I've checked the probable fix into both 1.2 and 1.3 trees.
>
>  -- Keir
>



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