Obliczeniowe szacowanie czasu wykonania programu

Określenie czasu wykonywania programu poprzez jego uruchomienie nie zawsze jest możliwe w zagadnieniach praktycznych, przykładowo w kompilacji iteracyjnej, ze względu na duże wydłużenie czasu tworzenia oprogramowania. Jednakże w wielu sytuacjach nie ma potrzeby dokładnego określenia tego czasu; wystarczyłoby go oszacować. W niniejszym artykule przedstawiono propozycję sposobu obliczeniowego szacowania czasu wykonania programu w oparciu o samą postać jego kodu źródłowego i znane parametry środowiska sprzętowego.

The program execution time is one of criteria which are taken into account during assessment of widely comprehended software quality. The general purpose is to make program execution time as short as possible. The program execution time depends on many, very different, factors. The most obvious of these are: the form of its source code and the hardware environment in which the program is executed. In practice, even a very minor change in the form of the source code of a program can result in a significant change in its execution time. The same effect can be caused by a slight change in the values of hardware parameters. Although the interpretation of program execution time as a quality assessment criterion is very simple, it is sometimes very difficult to precisely measure program execution and taking necessary measurements requires running the program. However, there is very often no need to know this time precisely; it would be sufficient to estimate it with some error which is known in advance. The paper presents - using the matrix multiplication problem for reference - a proposal of a method which can be used for estimating the execution time of a program, based only on its source code and a priori known hardware parameters. The idea of the proposed method is to elaborate a mathematical model combining statistical approach and the Wolfe's method for calculating data locality. The paper discusses the results of using the elaborated model on a control sample and indicates directions of further works.