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Subject[PATCH 09/10] tracing: Remove obsolete sched_switch tracer
From: Steven Rostedt <srostedt@redhat.com>

The trace events sched_switch and sched_wakeup do the same thing
as the stand alone sched_switch tracer does. It is no longer needed.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
Documentation/trace/ftrace.txt | 110 -------------------------------------
kernel/trace/trace_sched_switch.c | 48 ----------------
2 files changed, 0 insertions(+), 158 deletions(-)
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 557c1ed..65eddb7 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -202,10 +202,6 @@ Here is the list of current tracers that may be configured.
to draw a graph of function calls similar to C code
source.

- "sched_switch"
-
- Traces the context switches and wakeups between tasks.
-
"irqsoff"

Traces the areas that disable interrupts and saves
@@ -273,39 +269,6 @@ format, the function name that was traced "path_put" and the
parent function that called this function "path_walk". The
timestamp is the time at which the function was entered.

-The sched_switch tracer also includes tracing of task wakeups
-and context switches.
-
- ksoftirqd/1-7 [01] 1453.070013: 7:115:R + 2916:115:S
- ksoftirqd/1-7 [01] 1453.070013: 7:115:R + 10:115:S
- ksoftirqd/1-7 [01] 1453.070013: 7:115:R ==> 10:115:R
- events/1-10 [01] 1453.070013: 10:115:S ==> 2916:115:R
- kondemand/1-2916 [01] 1453.070013: 2916:115:S ==> 7:115:R
- ksoftirqd/1-7 [01] 1453.070013: 7:115:S ==> 0:140:R
-
-Wake ups are represented by a "+" and the context switches are
-shown as "==>". The format is:
-
- Context switches:
-
- Previous task Next Task
-
- <pid>:<prio>:<state> ==> <pid>:<prio>:<state>
-
- Wake ups:
-
- Current task Task waking up
-
- <pid>:<prio>:<state> + <pid>:<prio>:<state>
-
-The prio is the internal kernel priority, which is the inverse
-of the priority that is usually displayed by user-space tools.
-Zero represents the highest priority (99). Prio 100 starts the
-"nice" priorities with 100 being equal to nice -20 and 139 being
-nice 19. The prio "140" is reserved for the idle task which is
-the lowest priority thread (pid 0).
-
-
Latency trace format
--------------------

@@ -491,79 +454,6 @@ x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6]
latencies, as described in "Latency
trace format".

-sched_switch
-------------
-
-This tracer simply records schedule switches. Here is an example
-of how to use it.
-
- # echo sched_switch > current_tracer
- # echo 1 > tracing_enabled
- # sleep 1
- # echo 0 > tracing_enabled
- # cat trace
-
-# tracer: sched_switch
-#
-# TASK-PID CPU# TIMESTAMP FUNCTION
-# | | | | |
- bash-3997 [01] 240.132281: 3997:120:R + 4055:120:R
- bash-3997 [01] 240.132284: 3997:120:R ==> 4055:120:R
- sleep-4055 [01] 240.132371: 4055:120:S ==> 3997:120:R
- bash-3997 [01] 240.132454: 3997:120:R + 4055:120:S
- bash-3997 [01] 240.132457: 3997:120:R ==> 4055:120:R
- sleep-4055 [01] 240.132460: 4055:120:D ==> 3997:120:R
- bash-3997 [01] 240.132463: 3997:120:R + 4055:120:D
- bash-3997 [01] 240.132465: 3997:120:R ==> 4055:120:R
- <idle>-0 [00] 240.132589: 0:140:R + 4:115:S
- <idle>-0 [00] 240.132591: 0:140:R ==> 4:115:R
- ksoftirqd/0-4 [00] 240.132595: 4:115:S ==> 0:140:R
- <idle>-0 [00] 240.132598: 0:140:R + 4:115:S
- <idle>-0 [00] 240.132599: 0:140:R ==> 4:115:R
- ksoftirqd/0-4 [00] 240.132603: 4:115:S ==> 0:140:R
- sleep-4055 [01] 240.133058: 4055:120:S ==> 3997:120:R
- [...]
-
-
-As we have discussed previously about this format, the header
-shows the name of the trace and points to the options. The
-"FUNCTION" is a misnomer since here it represents the wake ups
-and context switches.
-
-The sched_switch file only lists the wake ups (represented with
-'+') and context switches ('==>') with the previous task or
-current task first followed by the next task or task waking up.
-The format for both of these is PID:KERNEL-PRIO:TASK-STATE.
-Remember that the KERNEL-PRIO is the inverse of the actual
-priority with zero (0) being the highest priority and the nice
-values starting at 100 (nice -20). Below is a quick chart to map
-the kernel priority to user land priorities.
-
- Kernel Space User Space
- ===============================================================
- 0(high) to 98(low) user RT priority 99(high) to 1(low)
- with SCHED_RR or SCHED_FIFO
- ---------------------------------------------------------------
- 99 sched_priority is not used in scheduling
- decisions(it must be specified as 0)
- ---------------------------------------------------------------
- 100(high) to 139(low) user nice -20(high) to 19(low)
- ---------------------------------------------------------------
- 140 idle task priority
- ---------------------------------------------------------------
-
-The task states are:
-
- R - running : wants to run, may not actually be running
- S - sleep : process is waiting to be woken up (handles signals)
- D - disk sleep (uninterruptible sleep) : process must be woken up
- (ignores signals)
- T - stopped : process suspended
- t - traced : process is being traced (with something like gdb)
- Z - zombie : process waiting to be cleaned up
- X - unknown
-
-
ftrace_enabled
--------------

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 8f758d0..7e62c0a 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -247,51 +247,3 @@ void tracing_sched_switch_assign_trace(struct trace_array *tr)
ctx_trace = tr;
}

-static void stop_sched_trace(struct trace_array *tr)
-{
- tracing_stop_sched_switch_record();
-}
-
-static int sched_switch_trace_init(struct trace_array *tr)
-{
- ctx_trace = tr;
- tracing_reset_online_cpus(tr);
- tracing_start_sched_switch_record();
- return 0;
-}
-
-static void sched_switch_trace_reset(struct trace_array *tr)
-{
- if (sched_ref)
- stop_sched_trace(tr);
-}
-
-static void sched_switch_trace_start(struct trace_array *tr)
-{
- sched_stopped = 0;
-}
-
-static void sched_switch_trace_stop(struct trace_array *tr)
-{
- sched_stopped = 1;
-}
-
-static struct tracer sched_switch_trace __read_mostly =
-{
- .name = "sched_switch",
- .init = sched_switch_trace_init,
- .reset = sched_switch_trace_reset,
- .start = sched_switch_trace_start,
- .stop = sched_switch_trace_stop,
- .wait_pipe = poll_wait_pipe,
-#ifdef CONFIG_FTRACE_SELFTEST
- .selftest = trace_selftest_startup_sched_switch,
-#endif
-};
-
-__init static int init_sched_switch_trace(void)
-{
- return register_tracer(&sched_switch_trace);
-}
-device_initcall(init_sched_switch_trace);
-
--
1.7.2.3



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