G'Day dtrace-discuss,
I saw an opportunity to demo DTrace recently, but jstack() for the Oracle
JVM keeps returning incomplete stacks. I've tried a number of different JDK
versions from 6 to 8, and options including libdtrace_forceload.so. Anyone
know of a JDK version or workaround that does jstack() reliably?
# dtrace -n 'profile-99 /execname == "java"/ { @[jstack(100, 8000)] =
count(); }'
[...]
org/mozilla/javascript/ScriptableObject.createSlot(Ljava/lang/String;II)Lorg/mozilla/javascript/ScriptableObject$Slot;*
0x884acce8200002da
1
sun/nio/ch/SocketChannelImpl.read(Ljava/nio/ByteBuffer;)I*
0xffffffff20007f4b
1
org/mozilla/javascript/ScriptRuntime.newObjectLiteral([Ljava/lang/Object;[Ljava/lang/Object;[ILorg/mozilla/javascript/Context;Lorg/mozilla/javascript/Scriptable;)Lorg/mozilla/javascript/Scriptable;*
0xa20000041
1
[...]
A flame graph based on this output is more than 50% stacks like this. It
looks a lot like omit frame pointer optimization, but there is no
-XX:-omit-frame-pointer option I can find. :-)
I can use other profilers, but wanted to give DTrace a shot at this. Thanks,
Brendan
--
http://www.brendangregg.com
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