powerpc ftrace functionality

powerpc ftrace functionality

[Lee Nipper]

Is ftrace functional with latest kernel on powerpc (32-bit) ?

I was checking basic functionality using the README steps.
The output of tracing/trace includes the header but nothing more (no trace lines).
It appears broken unless I'm missing something.

Below is the interaction.

Lee

# mkdir /debug
# mount -t debugfs nodev /debug
# cat /debug/tracing/available_tracers
wakeup function sched_switch nop
# cat /debug/tracing/current_tracer
nop
# echo sched_switch > /debug/tracing/current_tracer
# cat /debug/tracing/current_tracer
sched_switch
# cat /debug/tracing/trace_options
print-parent nosym-offset nosym-addr noverbose noraw nohex nobin noblock nostack
trace nosched-tree ftrace_printk noftrace_preempt nobranch annotate nouserstackt
race nosym-userobj noprintk-msg-only 
# echo 1 > /debug/tracing/tracing_enabled
# sleep 1
# cat /debug/tracing/trace > /tmp/trace.txt
# echo 0 > /debug/tracing/tracing_enabled
# cat /tmp/trace.txt
# tracer: sched_switch
#
#           TASK-PID    CPU#    TIMESTAMP  FUNCTION
#              | |       |          |         |
#
#
#
# uname -a
Linux freescale 2.6.29-rc2-00013-gf3b8436 #12 Mon Jan 19 11:28:33 CST 2009 ppc unknown
# 
# gunzip -c - < /proc/config.gz | egrep 'FTRACE|FUNCTION|SCHED_TRACER'
CONFIG_HAVE_FUNCTION_TRACER=y
CONFIG_HAVE_DYNAMIC_FTRACE=y
CONFIG_HAVE_FTRACE_MCOUNT_RECORD=y
CONFIG_FUNCTION_TRACER=y
CONFIG_SCHED_TRACER=y
CONFIG_DYNAMIC_FTRACE=y
CONFIG_FTRACE_MCOUNT_RECORD=y
CONFIG_FTRACE_SELFTEST=y
CONFIG_FTRACE_STARTUP_TEST=y
# dmesg | grep trace
ftrace: allocating 8054 entries in 40 pages
Testing tracer nop: PASSED
Testing tracer sched_switch: PASSED
Testing tracer function: PASSED
Testing dynamic ftrace: PASSED
Testing tracer wakeup: PASSED
# 

Re: powerpc ftrace functionality

[Lee Nipper]

On Mon, 2009-01-19 at 13:51 -0700, Lee Nipper wrote:
> Is ftrace functional with latest kernel on powerpc (32-bit) ?

> It appears broken unless I'm missing something.


FWIW, 2.6.29-rc2 powerpc ftrace works with one patch
from Steven Rostedt added in:

http://git.kernel.org/?p=linux/kernel/git/rostedt/linux-2.6-trace.git;a=commit;h=082605de5f82eb692cc90f7fda071cc01bb5ac34

-Lee