Messages in this thread |  | | Date | Wed, 4 Dec 2013 22:49:25 -0500 | Subject | Re: [PATCH 0/3] ARM Coresight: Enhance ETM tracing control | From | Adrien Vergé <> |
| |
2013/12/4 Greg Kroah-Hartman <gregkh@linuxfoundation.org>: > How much overhead does the existing tracing code have on ARM? Is ETM > still even needed? Why not just use ETM for the core tracing code > instead?
Coresight ETM is not just faster than /sys/kernel/debug/tracing, it provides more detailed and customisable info. For instance, you can trace every load, store, instruction fetch, along with the number of cycles taken, with almost zero-overhead.
> What's wrong with the in-kernel tracing logic that you can't use that > instead of the ETM stuff?
ETM has a different purpose. Integrating it in /sys/kernel/debug/tracing would not take advantage of all its features.
|  |