Messages in this thread | | | Date | Fri, 31 Mar 2017 07:25:50 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH 0/4] ftrace: Add 'function-fork' trace option (v1) |
| |
On Thu, 30 Mar 2017 09:49:29 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
> On Thu, 30 Mar 2017 10:40:46 +0900 > Namhyung Kim <namhyung@kernel.org> wrote: > > > Hi Masami, > > > > On Thu, Mar 30, 2017 at 9:54 AM, Masami Hiramatsu <mhiramat@kernel.org> wrote: > > > On Wed, 29 Mar 2017 10:46:21 +0900 > > > Namhyung Kim <namhyung@kernel.org> wrote: > > > > > >> Hello, > > >> > > >> This patchset add 'function-fork' option to function tracer which > > >> makes pid filter to be inherited like 'event-fork' does. During the > > >> test, I found a bug of pid filter on an instance directory. The patch > > >> 1 fixes it and maybe it should go to the stable tree. > > >> > > >> The function-fork option is disabled by default as event-fork does, > > >> but we might consider changing the default since it seems to be more > > >> natural from an user's perspective IMHO. > > > > > > By the way, I thought that event-fork option also effected to > > > function tracer. Is there any reason we should separate those? > > > I mean, we can add "trace-fork" option instead of "function-fork" > > > for setting both pid filters at once. > > > > > > Thank you, > > > > I'm ok with combining two options. > > > > I prefer not. Mainly because they are two different mechanisms, and > only event-fork is available now.
That sounds like implementation issue. From the viewpoint of users, they may want to use just one knob to filter both. And I didn't suggest replacing event-fork, but adding trace-fork for both, like a superset option.
> trace-cmd will use ptrace if function > fork is needed. Having it separate will let trace-cmd know if it needs > to use ptrace or not for function forking.
Yeah, that's a good workaround for older kernel.
Thank you,
-- Masami Hiramatsu <mhiramat@kernel.org>
| |