On Thu, 10 Sep 2020 17:54:54 +0900 Masami Hiramatsu mhiramat@kernel.org wrote:
Hi,
Here is the 3rd version of the series to improve the boot-time tracing to support kretprobe and tracing_on option. Previous version is here:
https://lkml.kernel.org/r/159894698993.1478826.2813843560314595660.stgit@dev...
This version adds uprobe %return suffix support ([5/8]) and the testcases ([8/8]), and update kprobe %suffix support([4/8]) and the uprobe event document([6/8]).
The combination of tracing_on and kretprobe allows us to trace events while a specific function call period. For example, the below bootconfig will make a function callgraph in the pci_proc_init() function at boot time.
ftrace { tracing_on = 0 # off at start tracer = function_graph event.kprobes { start_event { probes = "pci_proc_init" actions = "traceon" } end_event { probes = "pci_proc_init%return" actions = "traceoff" } } }
Here is the example output;
[..]
Hi Masami,
This looks really great! I just got back from a 10 day holiday, and I'm drowning in "catch-up". I plan on looking at all this relatively soon (in a week or two?). I just don't want you to think I'm ignoring this.
-- Steve