Messages in this thread | | | Date | Tue, 22 Feb 2022 10:52:18 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH] arm64/ftrace: Make function graph use ftrace directly |
| |
On Tue, 22 Feb 2022 21:00:49 +0800 Chengming Zhou <zhouchengming@bytedance.com> wrote:
> As we do in commit 0c0593b45c9b ("x86/ftrace: Make function graph > use ftrace directly"), we don't need special hook for graph tracer, > but instead we use graph_ops:func function to install return_hooker. > > Since commit 3b23e4991fb6 ("arm64: implement ftrace with regs") add > implementation for FTRACE_WITH_REGS on arm64, we can easily adopt > the same optimization on arm64.
Note. Ideally we want it to hook with DYNAMIC_FTARCE_WITH_ARGS, and not FTRACE_WITH_REGS. If arm64 is like x86_64, saving all regs at every function call has a bit more overhead than saving the minimum. The DYNAMIC_FTRACE_WITH_ARGS, means that the minimum is still saved, but now exposes the arguments and the stack pointer, which function_graph_tracer needs.
-- Steve
> > Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> > ---
| |