[ltt-dev] lttng for nommu cpus

[ltt-dev] lttng for nommu cpus

[andy]

Hi

I try to investigate performance issues on a cpu (blackfin)  that does
not have mmu.
I have ported a lttng patch, but unfortunately it does not work, as
relayfs is not supported
on mmu-less cpus.
A Call to allocte buffers in relayfs lead to vmap(), which is not
supported on mmu-less
systems

Is there any flavor of lttng that has been reported to work on mmu-less system?
Any links?

Thank you,
Andy

[ltt-dev] lttng for nommu cpus

[Mathieu Desnoyers]

* andy (rootstrap at googlemail.com) wrote:
> Hi
> 
> I try to investigate performance issues on a cpu (blackfin)  that does
> not have mmu.
> I have ported a lttng patch, but unfortunately it does not work, as
> relayfs is not supported
> on mmu-less cpus.
> A Call to allocte buffers in relayfs lead to vmap(), which is not
> supported on mmu-less
> systems
> 
> Is there any flavor of lttng that has been reported to work on mmu-less system?
> Any links?
> 

The latest LTTng versions implement a ltt-relay-alloc module which is a
fork from the original relay. It does not depend on vmap'd memory at
all, so it should be fine with mmu-less cpus.

I'd be interested to merge your blackfin patches when they are ready.

Mathieu

> Thank you,
> Andy
> 
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> 

-- 
Mathieu Desnoyers
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