Preliminary review: Adding tracing of I/O calls

[Staffan Larsen]

Thanks, Jim. I'll come back with micro-benchmark numbers.

/Staffan

On 2 nov 2012, at 21:27, Jim Gish <jim.gish at oracle.com> wrote:

> Hi Staffan,
> 
> This looks fine to me as well, but I had the same question as Mandy about performance.  Given the sensitivity to changes in I/O it would be good to have some micro-benchmarks here.
> 
> Thanks,
>   Jim
> On 11/02/2012 04:12 PM, Mandy Chung wrote:
>> 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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