On 05/17/2012 03:48 PM, Steven Rostedt wrote:
trace-cmd copies the entire /sys/kernel/debug/tracing/events directory
into the data file (well it copies only the events you specify).
I thought perf did the same. It should be using what's in the perf.dat
file and not what's on the host.
I found that 'perf script' and 'perf report' works differently,
and I suppose 'perf script' is correct and 'perf report' isn't.
What I'm doing on PC host is:
1) Collect data with:
perf record -a -R -f -m 8192 -c 1 -e sched:sched_switch \
-e sched:sched_process_exit -e sched:sched_process_fork \
-e sched:sched_wakeup -e sched:sched_migrate_task [task]
2) Collect an output from 'perf script' and 'perf report', both looks
great.
3) Copy perf.data and contents of /proc/kallsyms to ARM target.
4) Next, on ARM target:
perf script --kallsyms=[kallsyms from PC host] -i [perf.data from PC host]
Looks good, all event names like 'sched_wakeup' or 'sched_switch' are shown.
5) Try:
perf report --kallsyms=[kallsyms from PC host] -i [perf.data from PC host]
--stdio
All event names are shown as 'unknown:unknown'.
"Cross-replaying" (perf sched replay) looks broken too.
Host results are:
run measurement overhead: 260 nsecs
sleep measurement overhead: 56109 nsecs
the run test took 1000054 nsecs
the sleep test took 1076170 nsecs
nr_run_events: 246
nr_sleep_events: 257
nr_wakeup_events: 123
target-less wakeups: 27
task 0 ( <unknown>: 3440), nr_events: 33
task 1 ( kworker/0:0: 3227), nr_events: 15
task 2 ( <unknown>: 0), nr_events: 125
task 3 ( plugin-containe: 1769), nr_events: 13
task 4 ( ksoftirqd/0: 3), nr_events: 5
task 5 ( kworker/2:2: 2023), nr_events: 3
task 6 ( perf: 3441), nr_events: 200
task 7 ( migration/2: 3091), nr_events: 3
task 8 ( kworker/1:0: 3104), nr_events: 158
task 9 ( urxvt: 2952), nr_events: 95
task 10 ( ksoftirqd/2: 3093), nr_events: 3
------------------------------------------------------------
#1 : 70.193, ravg: 70.19, cpu: 116.57 / 116.57
#2 : 70.607, ravg: 70.23, cpu: 116.61 / 116.58
#3 : 70.411, ravg: 70.25, cpu: 116.69 / 116.59
#4 : 70.386, ravg: 70.27, cpu: 116.72 / 116.60
#5 : 70.222, ravg: 70.26, cpu: 116.39 / 116.58
#6 : 70.361, ravg: 70.27, cpu: 116.40 / 116.56
#7 : 70.409, ravg: 70.28, cpu: 116.43 / 116.55
#8 : 70.368, ravg: 70.29, cpu: 116.50 / 116.55
#9 : 70.604, ravg: 70.32, cpu: 116.75 / 116.57
#10 : 70.578, ravg: 70.35, cpu: 116.79 / 116.59
Cross-replaying attempt is ('perf sched -i [perf.data from PC host] replay'):
run measurement overhead: 8099 nsecs
sleep measurement overhead: 159428 nsecs
the run test took 998913 nsecs
the sleep test took 1188048 nsecs
nr_run_events: 0
nr_sleep_events: 0
nr_wakeup_events: 0
------------------------------------------------------------
#1 : 0.058, ravg: 0.06, cpu: 0.00 / 0.00
#2 : 0.105, ravg: 0.06, cpu: 0.00 / 0.00
#3 : 0.027, ravg: 0.06, cpu: 0.00 / 0.00
#4 : 0.026, ravg: 0.06, cpu: 0.00 / 0.00
#5 : 0.035, ravg: 0.05, cpu: 0.00 / 0.00
#6 : 0.027, ravg: 0.05, cpu: 0.00 / 0.00
#7 : 0.027, ravg: 0.05, cpu: 0.00 / 0.00
#8 : 0.028, ravg: 0.05, cpu: 0.00 / 0.00
#9 : 0.029, ravg: 0.04, cpu: 0.00 / 0.00
#10 : 0.028, ravg: 0.04, cpu: 0.00 / 0.00
Dmitry
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