Framework for user-directed profile-driven optimizations

1. A method for using profiling to obtain application-specific, preferred parameter values for an application, the method comprising:

receiving identification of an application-specific parameter for which to obtain an application-specific value;

receiving augmented code for profiling the application-specific parameter;

profiling the parameter and collecting profile data by:

generating an instrumentation binary from an instrumentation build, the instrumentation binary containing at least one user-defined callback routine registered by the user in a profile initialization function;

executing a training run with one or more representative workloads using the instrumentation binary, the execution invoking the at least one user-defined callback routine to record at least one application-specific preferred parameter value for the application in the collected profile data;

analyzing the collected profile data using the at least one user-defined callback routine; and

generating a feedback-directed optimization (FDO) build using the collected profile data, the FDO build utilizing the at least one application-specific preferred parameter value recorded in the collected profile data for the profiled application-specific parameter.

2. The method of claim 1 wherein profiling is user-directed per-class global value profiling.

3. The method of claim 1 wherein profiling is user-directed per-site value profiling.

4. The method of claim 1 wherein profiling is user-directed per-site object value profiling.

5. The method of claim 1 wherein generating the FDO build, further comprises:

transforming, based on the profile data, an application-specific parameter value to a preferred value using a set of standard value profile transformations.

6. A method for user-directed per-class global value profiling, the method comprising:

receiving a user-defined profile instrumentation initialization routine, the profile instrumentation initialization routine initializing a counter to profile a parameter and registering a user-defined analysis call back routine, containing custom processing for profile data;

generating an instrumentation binary from an instrumentation build, the instrumentation binary containing at least one user-defined analysis callback routine registered by the user in a profile initialization function;

executing a training run with one or more representative workloads using the instrumentation binary, wherein the execution of the training run includes:

running a profile update function in a code location where the counter's value should be updated; and

executing a profile handler method, registered in the user-defined analysis callback routine, to process counter data and record a preferred parameter value for the profiled parameter; and

generating a feedback-directed optimization (FDO) build using profile data collected during execution of the training run.

7. The method of claim 1 further comprising defining a profile counter for the application-specific parameter to be profiled.

8. The method of claim 7 further comprising allocating one entry in the static counter array for the counter.

9. The method of claim 8 wherein allocation is done by calling a compiler extension for counter allocation.

10. The method of claim 1 further comprising allowing for profile counter address tracking by providing a special purpose declaration attribute for the profile counter.

11. The method of claim 1 further comprising allowing for profile initialization by providing a special purpose declaration attribute to designate a profile initialization function.

12. The method of claim 6 further comprising registering a user-defined analysis call back routine by using a GCC interface.

13. The method of claim 6 further comprising recording the preferred parameter value by using a GCC interface.