Merge pull request #4 from ErickReyesR/patch-2
criticalstat.py: check for required trace events
diff --git a/bcc/criticalstat.py b/bcc/criticalstat.py
index 87afe28..7bc65b1 100755
--- a/bcc/criticalstat.py
+++ b/bcc/criticalstat.py
@@ -8,6 +8,8 @@
import argparse
import ctypes as ct
import sys
+import subprocess
+import os.path
examples=""
@@ -36,6 +38,26 @@
elif args.preemptoff:
preemptoff = True
irqoff = False
+
+debugfs_path = subprocess.Popen ("cat /proc/mounts | grep -w debugfs" +
+ " | awk '{print $2}'",
+ shell=True,
+ stdout=subprocess.PIPE).stdout.read().split("\n")[0]
+
+if debugfs_path == "":
+ print("ERROR: Unable to find debugfs mount point");
+ sys.exit(0);
+
+trace_path = debugfs_path + "/tracing/events/preemptirq/";
+
+if (not os.path.exists(trace_path + "irq_disable") or
+ not os.path.exists(trace_path + "irq_enable") or
+ not os.path.exists(trace_path + "preempt_disable") or
+ not os.path.exists(trace_path + "preempt_enable")):
+ print("ERROR: required tracing events are not available\n" +
+ "Make sure the kernel is built with CONFIG_DEBUG_PREEMPT " +
+ "and CONFIG_PREEMPTIRQ_EVENTS enabled")
+ sys.exit(0)
bpf_text = """
#include <uapi/linux/ptrace.h>
