[Intel-gfx] uABI / Removing DRM_I915_LOW_LEVEL_TRACEPOINTS Kconfig

[Steven Rostedt]

On Mon, 17 Dec 2018 18:26:03 -0700
Michael Sartain <mikesart at fastmail.com> wrote:

> Ftrace and perf are fantastic, stable, very well known, and documented with
> ecosystems built around them. AMD already is doing exactly what we are asking
> for with tracepoints, and Intel has tracepoints that work right now. Please,
> there must be a way we can enable those and use the current tracing systems
> without it introducing a stable tracepoint uABI which promises it'll never
> change until the end of days?

Would it be helpful if we implemented a way that trace events would not
show up in the tracefs filesystem unless a specifc kernel command line
(or module) parameter was supplied?

That would make for trace events not to be visible by default, but
allow for the same kernel to make them visible with a simple reboot (or
module reload). Like adding an option: i915_debug_tracepoints ?

Or perhaps a sysrq switch?

-- Steve