Incorrect arguments is passed to sun.misc.Perf#createLong (original) (raw)

Yasumasa Suenaga suenaga.yasumasa at lab.ntt.co.jp
Fri Apr 19 05:07:55 UTC 2013

Hi Mandy,

Thank you so much for your cooperation.

FYI. While looking at the hotspot implementation, I found a bug that creates the long counter of incorrect type (it got VVariable and VMonotonic reverse). I have file a hotspot bug and suggested a patch:

I didn't realize it :-) Please fix it too!

Thanks,

Yasumasa

On 2013/04/19 5:41, Mandy Chung wrote:

I have pushed the changeset:http://hg.openjdk.java.net/jdk8/tl/jdk/rev/3b81fac25d26

FYI. While looking at the hotspot implementation, I found a bug that creates the long counter of incorrect type (it got VVariable and VMonotonic reverse). I have file a hotspot bug and suggested a patch: 8012641: PerfCreateLong creates perf counter of incorrect type Mandy On 4/17/13 2:26 PM, Mandy Chung wrote: Hi Yasumasa,

Thanks for the patch. I'm going to sponsor your fix for 8011934 and will be pushing it shortly. http://cr.openjdk.java.net/~mchung/jdk8/webrevs/8011934/webrev.00/ Mandy On 4/10/2013 6:59 PM, Yasu wrote: Hi Mandy,

On 4:59, Mandy Chung wrote: Hi Yasumasa,

I'm adding core-libs and bcc serviceability-dev to move this thread to core-libs for sun.misc.PerfCounter discussion. On 4/9/2013 4:50 AM, Yasu wrote: Hi,

I'm trying to create entry from Java program to hsperfdata through sun.misc.PerfCounter . First of all, sun.misc.PerfCounter is a private API that is not supported and may be changed and removed in any future release. I'm curious how you create a counter in hsperfdata through sun.misc.PerfCounter. The constructor is private. I've understood that sun.* packages is private API. I use PerfCounter with reflection API ( setAccessible(true) ) .

However, I cannot watch the updated value in my entry through the jstat with interval option. I guess this cause is that wrong arguments are passed from PerfCounter# to Perf#createLong .

Indeed - it's a bug that calls Perf.createLong with the incorrect parameters. I have filed a bug (8011934). Thanks! Have you signed the OCA [1]? Yes. I already sent OCA with my signature. Thanks, Yasumasa Thanks Mandy [1] http://openjdk.java.net/contribute/ sun.misc.PerfCounter: --------- private PerfCounter(String name, int type) { this.name = name; ByteBuffer bb = perf.createLong(name, UNone, type, 0L); bb.order(ByteOrder.nativeOrder()); this.lb = bb.asLongBuffer(); } --------- sun.misc.Perf: --------- public native ByteBuffer createLong(String name, int variability, int units, long value); --------- "type" in constructor of PerfCounter means "variability". So "type" should be set to 2nd argument in perf.createLong() perf.createLong() should be called as following: --------- ByteBuffer bb = perf.createLong(name, type, UNone, 0L); ---------

I've applied a patch which is attached in this email, it's works fine. Thanks, Yasumasa

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