dtrace discuss - Feb 2007 - dtrace, uint64 wrapping and the Java dtrace API

Hi,

 

I''m trying to understand the behaviour of dtrace regarding uint64
values...

I have this stupid script :

profile:::profile-1sec

{

        @rest=sum(walltimestamp);

        printa(@rest);

}
>From the shell, If a execute this script and wait, I have :
 [...]

  0  49239                    :profile-1sec

 7032413737193061074

 

  0  49239                    :profile-1sec

 8204482696890657210

 

  0  49239                    :profile-1sec

 -9070192416120335650

 

  0  49239                    :profile-1sec

 -7898123454421689444

[...]

 

How come that the uint64 value can be negative ? Might be a bug in the printa
function ? If so, I''ll enter a bug.

 

Now, if I use the Java dtrace API to execute this script (without the printa),
the AggregationValue contains a negative value and I have to "cast" my
value (with BigInteger and some magic)  to have a correct value.

Since AggregationValue.getValue return a Number object, I''ll assume
that returning a uint64 is not possible with the API without some work...

 

Seb

 

S?bastien BOUCHEX BELLOMI? - Senior Software Engineer 
INFOVISTA  SA 
6, rue de la Terre De Feu 
F-91952 Courtaboeuf Cedex 
Tel : +33 (0)1 64 86 79 72      Fax : +33 (0)1 64 86 79 79 
sbouchex at infovista.com <mailto:sbouchex at infovista.com>       
http://www.infovista.com <http://www.infovista.com>

 

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As with the trace() action, aggregation printing defaults to a signed
interpretation. If you want an unsigned value, you can include a format
for printa().

Tom, can probably address your questions about the Java API.

Adam

On Wed, Feb 21, 2007 at 03:53:04PM +0100, Sbastien Bouchex Bellomi
wrote:
> Hi,
> 
>  
> 
> I''m trying to understand the behaviour of dtrace regarding uint64
values...
> 
> I have this stupid script :
> 
> profile:::profile-1sec
> 
> {
> 
>         @rest=sum(walltimestamp);
> 
>         printa(@rest);
> 
> }
> 
> >From the shell, If a execute this script and wait, I have :
> 
>  [...]
> 
>   0  49239                    :profile-1sec
> 
>  7032413737193061074
> 
>  
> 
>   0  49239                    :profile-1sec
> 
>  8204482696890657210
> 
>  
> 
>   0  49239                    :profile-1sec
> 
>  -9070192416120335650
> 
>  
> 
>   0  49239                    :profile-1sec
> 
>  -7898123454421689444
> 
> [...]
> 
>  
> 
> How come that the uint64 value can be negative ? Might be a bug in the
printa function ? If so, I''ll enter a bug.
> 
>  
> 
> Now, if I use the Java dtrace API to execute this script (without the
printa), the AggregationValue contains a negative value and I have to
"cast" my value (with BigInteger and some magic)  to have a correct
value.
> 
> Since AggregationValue.getValue return a Number object, I''ll
assume that returning a uint64 is not possible with the API without some work...
> 
>  
> 
> Seb
> 
>  
> 
> S?bastien BOUCHEX BELLOMI? - Senior Software Engineer 
> INFOVISTA  SA 
> 6, rue de la Terre De Feu 
> F-91952 Courtaboeuf Cedex 
> Tel : +33 (0)1 64 86 79 72      Fax : +33 (0)1 64 86 79 79 
> sbouchex at infovista.com <mailto:sbouchex at infovista.com>       
http://www.infovista.com <http://www.infovista.com>
> 
>  
> 
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org
-- 
Adam Leventhal, Solaris Kernel Development       http://blogs.sun.com/ahl