Dear Thomas,
I found bug at settracer function of cyclictest.c source (rt-test ver 0.33).
settracer func use 10 times in the for() statement to searching tracer
like preemptoff , irqsoff , preemptirqsoff.
But, I think that we have to consider 10+ words in the available_tracers file.
[root@fedora9 tracing]# cd /debug/tracing/
[root@fedora9 tracing]# cat available_tracers
syscall blk kmemtrace power branch function_graph mmiotrace wakeup_rt
wakeup preemptirqsoff preemptoff irqsoff function sched_switch
initcall nop
[root@fedora9 tracing]# cat available_tracers | wc -w
16
[root@fedora9 tracing]#
[root@fedora9 tracing]# git clone
git://git.kernel.org/pub/scm/linux/kernel/git/clrkwllms/rt-tests.git
[root@fedora9 tracing]# cd rt-tests
[root@fedora9 tracing]# make clean ; make all
[root@fedora9 tracing]# ./cyclictest -n -t 3 -b 1000000 -P-D 2 --> Success
[root@fedora9 tracing]#./cyclictest -n -t 3 -b 1000000 -I -D 2 --> Failed
[root@fedora9 tracing]#./cyclictest -n -t 3 -b 1000000 -B-D 2 --> Failed
So I made patch file to consider above case.
If I mistake, correct me.
--------------------------------------------------
[root@fedora9 cyclictest]# diff -urN ./cyclictest.c.ori ./cyclictest.c
--- ./cyclictest.c.ori 2009-04-05 23:48:03.000000000 +0900
+++ ./cyclictest.c 2009-04-06 00:15:51.000000000 +0900
@@ -320,7 +320,7 @@
char name[100];
FILE *fp;
int ret;
- int i;
+ //int i;
/* Make sure tracer is available */
strncpy(filename, debugfileprefix, sizeof(filename));
@@ -330,7 +330,7 @@
if (!fp)
return -1;
- for (i = 0; i < 10; i++) {
+ while(1) {
ret = fscanf(fp, "%99s", name);
if (!ret) {
ret = -1;
--------------------------------------------------
After patching .....
[root@fedora9 tracing]#./cyclictest -n -t 3 -b 1000000 -I -D 2
[root@fedora9 tracing]# cat trace
# tracer: irqsoff
#
# irqsoff latency trace v1.1.5 on 2.6.29.1-rt4.20090403-ftrace-lgs
# --------------------------------------------------------------------
# latency: 108 us, #3/3, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
# -----------------
# | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0)
# -----------------
#
# _------=> CPU#
# / _-----=> irqs-off
# | / _----=> need-resched
# || / _---=> hardirq/softirq
# ||| / _--=> preempt-depth
# |||| /
# ||||| delay
# cmd pid ||||| time | caller
# \ / ||||| \ | /
<idle>-0 0d..1 3us!: acpi_idle_do_entry <-acpi_idle_enter_bm
<idle>-0 0.N.1 107us+: cpu_idle <-rest_init
<idle>-0 0.N.1 110us : trace_preempt_on <-rest_init
--
Regards,
GeunSik Lim
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Attachment:
fix-comparison-wordcount-available-tracers.patch
Description: Binary data
