International Business Machines Corporation

Gad Haber

Moshe Klausner

Vadim Eisenberg

Marcel Zalmanovici

Roy Levin

Maxim Gurevich

Shmuel Ur

Guy Bashkansky

Systems and methods for data profiling are provided. In one embodiment, the method comprises monitoring value of at least a target parameter during execution of logic code in a computing environment, wherein the value of the target parameter is incrementally updated in a sequence of data points; and using statistical analysis to determine a target value for the target parameter as of a current data point, in response to determining a change in the value of the target parameter at each data point.

Efficient data profiling to optimize system performance

A machine-independent representation of computer instructions can serve as a standard for machine instruction description that is suitable for post-link transformation tools, such as post-link optimizers, and for education of users. In one embodiment the instructions are presented as expression trees in a XML file. An optimizer operates on the transformed code representations, after which optimized code is re-transformed into machine-readable code.

Presenting machine instructions in a machine-independent tree form suitable for post-link optimizations

Device, system, and method of computer program optimization. For example, an apparatus to analyze a plurality of versions of computer program includes: a code analyzer to determine one or more code differences between first and second versions of the computer program, based on at least one optimization log associated with at least one of the first and second versions of the computer program.

Device, system, and method of computer program optimization

Methods and systems for computer program optimization utilize function cloning in program code, such as post-linked code. Each function call is directed to a different cloned version of the called function. Conventional profiling methods such as hardware event sampling, basic block profiling, and edge profiling may then be applied to the modified program code to obtain call path-based, clone-specific profile data. The profile data can be further exploited to optimize the program code.

Method for enabling profile-based call site tailor-ing using profile gathering of cloned functions

A method and system for profiling performance behaviour of executed loops. For each invocation of a loop, a count of a measured event is incremented. A display is provided for a loop () showing the number of measured events for each of the loop's invocations. The code of a loop is instrumented () to obtain the count of loop invocations () and the occurrences of the measured event ().

Profiling of performance behaviour of executed loops

A method for improving program performance including reordering a global data area of a program and for each load instruction referencing global variables within range of the immediate part of an add immediate instruction from a TOC anchor, replacing the load instruction with an add immediate instruction. The method may further include placing a TOC at the top, or within a predetermined distance from the top, of the global data area. The method may also include placing the global variables after the TOC, wherein more frequently referenced global variable are closer to the TOC than less frequently referenced global variables. Also, the method may further include placing in run-time order, groups of the global variables that frequently follow each other in run-time.

Reducing load instructions via global data reordering

A method for post-link code optimization by identifying cold caller functions of a hot callee function, and percolating store and restore instructions with respect to non-volatile registers from the callee function to the caller function.

Percolating hot function store/restores to colder calling functions

A post-link optimization method for renaming non-volatile registers with unused volatile registers, then removing the non-volatile register store/restore instructions from a function prolog/epilog. The volatile registers are saved before each function call and restored immediately afterwards. The optimization method is worthwhile if all of the call instructions are rarely invoked relative to the function prolog/epilog. The method requires that the hot function be disassembled, but does not require the full control flow graph.

Eliminating store/restores within hot function prolog/epilogs using volatile registers

A post-link optimization method for removing non-volatile register store/restore instructions from a hot function prolog/epilog, when the non-volatile register is referenced only in cold sections of code within the hot function. The method requires that the hot function be disassembled, but does not require the full control flow graph.

Eliminating cold register store/restores within hot function prolog/epilogs

A method for code optimization includes disassembling object code that has been compiled and linked, and identifying a function in the disassembled code, the function including store and restore instructions with respect to a register. The disassembled code is analyzed to locate a call to the function followed by an instruction to kill the register. The code is modified so as to eliminate the store instruction from the function when the function is invoked by the located call.

Growing community of inventors

Nesher, Israel

Gad Haber