Re: Microblaze - The fist year

From: Bill Davidsen
Date: Sun May 09 2010 - 12:49:47 EST


Michael Schnell wrote:
On 04/13/2010 03:27 PM, Michal Simek wrote:

yes, futex is there. You can check it in
arch/microblaze/include/asm/futex.h
Great ! I'll check how this is done.

Does Microblaze MMU Linux support SMP ?

It is possible to connect several MicroBlazes but the problem is
missing cache coherency modul. I hope that Xilinx will release any
version which will support it.
We haven't done any significant work to support it but it is expected
solution which will happen.

Besides cache coherency, another problem might be doing FUTEX. here (I
suppose) SMP safe atomic user space operations are necessary. many
simple RISK (load/store-) CPUs don't provide these (new ARMs provide
"load-locked / store-conditional" on that behalf as an extension to the
load/store paradigm. I suppose these can be done in an SMP-safe way,
supposedly using the hardware that provides cache coherency).

I wonder if you could make this work with some variant of NUMA configuration. I don't predict anything about being practical even if it works, just a thought.

--
Bill Davidsen <davidsen@xxxxxxx>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
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