hprof profiler output doesn't include line numbers regardless of `lineno` value

Question

I'm running

java -cp some:jars:out \
-agentlib:hprof=cpu=times,format=a,file=java.hprof.txt,lineno=y,doe=y com.foo.Benchmark \
< /dev/null

and in the output I get stack frames without line numbers

THREAD START (obj=50000150, id = 200002, name="HPROF gc_finish watcher", group="system")
THREAD START (obj=50000151, id = 200001, name="main", group="main")
THREAD START (obj=50000281, id = 200003, name="Thread-1", group="main")
THREAD END (id = 200003)
THREAD END (id = 200001)
THREAD START (obj=500002a5, id = 200004, name="DestroyJavaVM", group="main")
THREAD END (id = 200004)
TRACE 307081:
        com.foo.Benchmark.methodName(Benchmark.java:Unknown line)
        com.foo.Benchmark.anotherMethodName(Benchmark.java:Unknown line)
        ...

If I change lineno=y to lineno=n I still get Unknown line.

I compiled the classes with -g. My javac looks like

javac -g -Xlint -encoding UTF-8 -source 1.5 -d out -classpath ... src/main/com/foo/*.java

I checked the .class files to make sure they have line numbers:

javap -classpath out -c -l com.foo.Benchmark

shows plenty of things like

  LineNumberTable: 
   line 1077: 0
   line 1078: 8
   line 1079: 14
   line 1080: 21
   line 1082: 23
   line 1083: 31
   line 1084: 43

Am I using some flag combination that prevents line number output?

score 2 · Answer 1 · answered Mar 19 '12 at 17:09

I faced exactly the same problem, but compiling the source with -g helped. After compiling with -g, I see the line numbers like this (which I don't see otherwise, without -g option) -

LineNumberTable:
 line 16: 0
 line 17: 8
 line 18: 12
 line 19: 20
 line 18: 29
 line 21: 35

Now, if I run this -

java -cp "./build/classes" -agentlib:hprof=heap=sites,depth=20  org.sample.welcome.Main a b c

I do get the line numbers for the user-defined classes. Even though I am not sure what's going wrong in your case, these are my observations -

Using javac without -g: If I have -lineno (default y) set to y, I still don't see the line numbers for most of the classes except for the user-defined classes (Main in the above case). If I've set -lineno to n, then I won't see line numbers for any of the classes anyway.
Using javac with -g: If I have -lineno set to y, I can see the line numbers for all the classes (not sure what's going wrong in your case).

The only documentation I could find for HPROF doesn't say anything beyond this. I think one option would be to try with fewer optional arguments and see the results.

Note: I'm using JDK 1.6 in the above example

Thanks for the pointer. I no longer have this benchmark set up to run easily, but I'll keep this in mind. — Mike Samuel, Mar 19 '12 at 17:30
Mike's example uses `cpu=times` option, yours -- `heap=sites`. The later option does output the line number, the first does NOT. — Ilya Silvestrov, Nov 07 '17 at 19:53

hprof profiler output doesn't include line numbers regardless of `lineno` value

1 Answers1