Can you describe the # of processes you are running in your test. Is
it possible for you to try the tests w/2.6.29 from kernel.org?
- k
On May 6, 2009, at 7:42 AM, Morrison, Tom wrote:
I'm sorry I forgot to put that, this issue was found with our
currently running kernel 2.6.23.final (what comes with the
Freescale LTIB BSP package dated 05/23/2009).
I am sorry if I don't understand your statement that the SMP might
be broken on this kernel, because I tried to analyze the kernel that
came with the latest BSP LTIB [ackage from Freescale (dated 12/18/2009
(where we got the 4.2.171 compiler from)), and the associated 'switch
context' code is exactly the same. Unfortunately, I have not started
the process of porting my current platform's BSP to this new kernel -
otherwise, I would have done the test on that platform (this also
requires a new version of u-boot in order to test correctly))..
I may have mis-interpreted something and/or I am sure I don't
understand everything about the SMP resource management (and
associated SPE management), so thank you for any insight you
may have on this front...
Tom
-----Original Message-----
From: Kumar Gala [mailto:ga...@kernel.crashing.org]
Sent: Wednesday, May 06, 2009 8:32 AM
To: Morrison, Tom
Cc: Michael Neuling; linuxppc-dev@ozlabs.org
Subject: Re: MSR_SPE - being turned off...
On May 6, 2009, at 3:31 AM, Morrison, Tom wrote:
Kumar,
What about the case of a context switch (i.e.: when things are
setup
in registers for the SPE, but then a context switch happens before
the SPE is executed)?
context switches will be fine. What we normally do is keep track of
which user app used SPE last and when some other app needs it we
clear
MSR_SPE for the old app, save its registers. Than we load up the
registers for the new app and set MSR_SPE. When the old app context
switches in it will get an SPE unavail exception at the point it
executes its next SPE insn and we will repeat the process.
As to load_up_spe & give_up_spe, it was pointed out to me tonight
by
a co-worker
to look at how things are saved in those routines, I definitely
will
look at this again,
c>> > and see how it is done...
This is happening for us on an 8572 SMP. We are trying to get it to
happen
on 8548 (and single core 8572), but we haven't been able to push
this part
of the application as hard as it is being pushed on 8572...but we
will keep trying....
Again, what kernel version for 8572? Its possible old SMP kernels
are
broken on 8572.
- k
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