Large number of failures on leon3
joel at rtems.org
Tue Mar 21 21:26:12 UTC 2017
On Tue, Mar 21, 2017 at 5:17 AM, Jiri Gaisler <jiri at gaisler.se> wrote:
> The culprit seems to be the CASA instruction. The leon3 bsp is built to
> always need this instruction, regardless if SMP is enabled or not. The sis
> simulator does not support CASA at the moment, hence the failures. The
> erc32 and leon2 bsp does not use CASA since the hardware does not support
> it. If the leon3 bsp is supposed to always require CASA, then it should be
> noted in the bsp documentation as not all leon3 hardware actually supports
Hmmm... I let this sit so I could think. I wanted to make sure we didn't
head down a path of needing another BSP variant or multilib variant
Where is this instruction used? I didn't see it in the port or BSP. But
again "grep -i cas" has a LOT of output.
Do all SMP configurations have CASA?
Is the instruction optional in uniprocessor configurations? If so, is
there a case where you must use it in uniprocessor configurations?
Is this something in gcc (atomics?) that needs to be more conditional
on the CPU model? And.. could that push us to a multilib variant?
Sorry for sounding confused. I just would like to understand when
the instruction is present and which knob settings we have to set
and how to know when it is OK to use. So it starts with knowing
when it is available in HW, when gcc might use it, etc.
> On 03/19/2017 02:32 PM, Joel Sherrill wrote:
> I was following up on Gedare's testing and tried leon3. There
> were a surprising number of failures there with SMP disabled.
> This is testing with gdb. Does anyone else get the same
> results with qemu or tsim? Any idea what's broken?
> Passed: 458
> Failed: 20
> Timeouts: 73
> Invalid: 3
> Total: 554
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