Re: Error using cyclictest's tracing

[Beethovenklc <beethovenklc@gmail.com>]

My mistake. Now its working. I've messed up and chose a different kernel 
build without tracing.

Thanks!


On 11/07/15 00:57, Beethovenklc wrote:
> Hello.
>
> This is my first time posting in this newsgroup, here from Argentina :D
>
> I'm trying to sort out some latency problems on a system with Ubuntu
> 14.04 LTS, kernel version 3.14.39-rt37 with rt-preempt patch and tracers
> enabled and AMD A10-6800K with 4 core of 4GHz CPU.
>
> I'm having problems using cyclictest with -t flag to have more
> information regarding unpredictable latency peaks, but it shows an error.
>
> $ sudo ./cyclictest -n -p99 -b200
> # /dev/cpu_dma_latency set to 0us
> INFO: debugfs mountpoint: /sys/kernel/debug/tracing/
> WARN: tracing_enabled or tracing_on not found
> debug fs not mounted, TRACERs not configured?
> could not set ftrace_enabled to 0
> FATAL: Can't open /sys/kernel/debug/tracing/available_tracers for reading
>
>
> When I list "/sys/kernel/debug" I get
>
>
> sudo ls /sys/kernel/debug/
> acpi        dma_buf       frontswap  kvm-guest  regulator     virtio-ports
> bdi        dri           gpio       mce     sched_features  wakeup_sources
> bluetooth   dynamic_debug  hid          pinctrl     sleep_time     x86
> cleancache  eeepc-wmi       kprobes    pwm     suspend_stats
> clk        extfrag       kvm          regmap     usb
>
>
> It seems "tracing" folder is not present.. I've read that this folder is
> created when you use ftrace. Kernel was compiled with ftrace and tracers
> as you can see in my kernel .config file:
>
>
> $ cat .config | grep _FTRACE
> CONFIG_KPROBES_ON_FTRACE=y
> CONFIG_HAVE_KPROBES_ON_FTRACE=y
> # CONFIG_PSTORE_FTRACE is not set
> CONFIG_HAVE_DYNAMIC_FTRACE=y
> CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS=y
> CONFIG_HAVE_FTRACE_MCOUNT_RECORD=y
> CONFIG_FTRACE=y
> CONFIG_FTRACE_SYSCALLS=y
> CONFIG_DYNAMIC_FTRACE=y
> CONFIG_DYNAMIC_FTRACE_WITH_REGS=y
> CONFIG_FTRACE_MCOUNT_RECORD=y
> # CONFIG_FTRACE_STARTUP_TEST is not set
>
>
> $ cat .config | grep _TRACE
> # CONFIG_TREE_RCU_TRACE is not set
> CONFIG_SYSCTL_EXCEPTION_TRACE=y
> CONFIG_TRACEPOINTS=y
> CONFIG_HAVE_ARCH_TRACEHOOK=y
> CONFIG_NETFILTER_XT_TARGET_TRACE=m
> # CONFIG_SCSI_IPR_TRACE is not set
> # CONFIG_VXGE_DEBUG_TRACE_ALL is not set
> # CONFIG_ATH5K_TRACER is not set
> CONFIG_CAPI_TRACE=y
> CONFIG_TRACE_ROUTER=m
> CONFIG_TRACE_SINK=m
> CONFIG_TRACE_IRQFLAGS_SUPPORT=y
> CONFIG_TRACE_IRQFLAGS=y
> # CONFIG_RCU_TRACE is not set
> CONFIG_NOP_TRACER=y
> CONFIG_HAVE_FUNCTION_TRACER=y
> CONFIG_HAVE_FUNCTION_GRAPH_TRACER=y
> CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST=y
> CONFIG_HAVE_SYSCALL_TRACEPOINTS=y
> CONFIG_TRACER_MAX_TRACE=y
> CONFIG_TRACE_CLOCK=y
> CONFIG_CONTEXT_SWITCH_TRACER=y
> CONFIG_GENERIC_TRACER=y
> CONFIG_FUNCTION_TRACER=y
> CONFIG_FUNCTION_GRAPH_TRACER=y
> CONFIG_IRQSOFF_TRACER=y
> CONFIG_PREEMPT_TRACER=y
> CONFIG_SCHED_TRACER=y
> CONFIG_TRACER_SNAPSHOT=y
> CONFIG_TRACER_SNAPSHOT_PER_CPU_SWAP=y
> CONFIG_STACK_TRACER=y
> CONFIG_BLK_DEV_IO_TRACE=y
>
>
> Did I miss something?
>
> Thanks!
>
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