Re: [RFC] ftrace: support tracing functions in one module

[Arnaldo Carvalho de Melo <acme@redhat.com>]

Em Mon, Aug 04, 2008 at 10:11:17AM +0800, Ming Lei escreveu:
> 2008/8/3 Steven Rostedt <rostedt@goodmis.org>:
> >
> > On Sun, 3 Aug 2008, Ming Lei wrote:
> >
> >> Hi,
> >>
> >> IMO, ftrace is a very good tools, which can monitor almost all
> >> functions calling
> >> in the running kernel. The traced result is very complete and intact.
> >> But it seems
> >> too large to grasp the interested content.  For example, one may only
> >> have interest in
> >> functions calling in usbcore.ko, but he must trace all the functions
> >> calling in the
> >> kernel, so the tracing result is too large to use it.
> >>
> >> Could you add the support of tracing functions in one module only to ftrace?
> >
> > Look at the set_ftrace_filter in ftrace.txt. You can pick and choose which
> > functions to trace.  All the functions that can be traced is in
> 
> It seems not ver easy to opearte to trace all functions in a module. You need to
> write all function names to set_ftrace_filter. Also some functions have
> same names in kernel and modules. This can lead to some messed trace result.
> 
> Do you have the plan to support tracing functions in one module or in one kernel
> address range?

What about using:

[acme@doppio pahole]$ nm --defined-only /usr/lib/debug/lib/modules/2.6.24.7-75.el5rt/kernel/drivers/net/tg3.ko.debug | grep ' t ' | cut -d' ' -f3 | head 
__tg3_set_coalesce
__tg3_set_mac_addr
__tg3_set_rx_mode
_tw32_flush
tg3_5700_link_polarity
tg3_abort_hw
tg3_alloc_rx_skb
tg3_ape_driver_state_change
tg3_bmcr_reset
tg3_change_mtu
[acme@doppio pahole]$

Feed this to /sys/kernel/debug/tracing/set_ftrace_filter and you should
be set, no?

Ok, you need to have the kernel-debuginfo package installed, and I guess
we can get away with that, but for now, isn't that enough?

- Arnaldo