Preliminary review: Adding tracing of I/O calls (original) (raw)

Mandy Chung mandy.chung at oracle.com
Fri Nov 2 20:12:33 UTC 2012


Hi Staffan,

On 11/2/2012 11:36 AM, Staffan Larsen wrote:

This is a preliminary review request for adding an API for tracing I/O calls. For now, this is an empty infrastructure intended to enable diagnosing/tracing of i/o calls. A user of the API can register a listener and get callbacks for read and write operations on sockets and files. It does not (yet) cover asynchronous i/o calls. When not used, the implementation should add a minimum of overhead. To provide useful information to the user, FileInputStream, FileOutputStream and RandomAccessFile have been modified to keep track of the path they operate on (when available).

Webrev: http://cr.openjdk.java.net/~sla/iotrace/webrev.00/

This looks okay to me.

Minor comments: sun/misc/IoTrace.java L36: should it be volatile in case another thread is setting to another listener?

The *Begin() methods return a "handle" that will be passed to the *End() methods. Have you considered to define a type for it rather than Object?

Do you have any performance measurement result that you can share? As for the unit tests, I know you have tests written for the feature that implements the listeners. I wonder if it's worth adding some sanity tests along with this change?

Mandy

Feedback is most welcome, /Staffan



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