Re: [PATCH 0/3] ARM Coresight: Enhance ETM tracing control

[Adrien VergÃ]

2013/12/4 Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>:
> Your pid implementation is broken, see my other email about that :(

Thank you for your remarks on pid. I'll try to correct that.

> And again, what's wrong with the existing tracing functionalty that is
> processor agnostic?  Why can't we just delete this driver today and use
> the existing trace code?

As far as I know, the tracing functionality in
/sys/kernel/debug/tracing does not take advantage of ETM. ETM is a
dedicated hardware that greatly reduces tracing overhead. It only
exists on ARM platforms.

I understand using sysfs here is not the cleanest way. I patched my
kernel to meet my needs (trace a specific process or address range),
and I thought these small modifications could be useful -- until
bigger work is done to remove ETM control from sysfs.

Do you think it's worth correcting my patch (for pid namespaces) and
re-submitting it? Or should we wait for someone to port ETM tracing to
debugfs?

Thanks,

Adrien
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