From mboxrd@z Thu Jan 1 00:00:00 1970 From: Beethovenklc Subject: Error using cyclictest's tracing Date: Sat, 11 Jul 2015 00:57:51 -0300 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit To: linux-rt-users@vger.kernel.org Return-path: Received: from plane.gmane.org ([80.91.229.3]:41060 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751602AbbGKHAO (ORCPT ); Sat, 11 Jul 2015 03:00:14 -0400 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1ZDlxK-0003u4-K1 for linux-rt-users@vger.kernel.org; Sat, 11 Jul 2015 06:00:03 +0200 Received: from 71-205-16-190.fibertel.com.ar ([190.16.205.71]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 11 Jul 2015 06:00:02 +0200 Received: from beethovenklc by 71-205-16-190.fibertel.com.ar with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 11 Jul 2015 06:00:02 +0200 Sender: linux-rt-users-owner@vger.kernel.org List-ID: 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!