On Wed, 2020-08-26 at 15:32 -0400, Steven Rostedt wrote: > On Tue, 25 Aug 2020 08:53:25 -0700 > Joe Perches <j...@perches.com> wrote: > > > > The print buffer is statically allocated and managed using code borrowed > > > from __ftrace_trace_stack() and is limited to 256 bytes (four of these > > > are allocated per CPU to handle the various contexts); anything larger > > > will be truncated. > > > > There is an effort to avoid using trace_printk and the like > > so perhaps this feature should have the same compile time > > guard. > > No, this is fine for being in a production kernel. Basically, these are > simply debug printk()s that can also be put into the trace buffer. The > key difference to trace_printk() is that they are an event that needs > to be enabled to write into the buffer.
It just seems like a backdoor way to convert various pr_debug functions (dev_dbg/netdev_dbg, et al) into tracing. What's the real value? Timing data? Something else?
