Messages in this thread |  | | Date | Wed, 4 Dec 2013 16:12:56 -0500 | Subject | Re: [PATCH 0/3] ARM Coresight: Enhance ETM tracing control | From | Adrien Vergé <> |
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2013/12/4 Greg Kroah-Hartman <gregkh@linuxfoundation.org>: > 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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