206588088
A Practical Tool for Detecting Races in OpenMP Programs
Detecting data races or just races is important for debugging OpenMP programs, because races result in unintended nondeterministic executions of the program. The previous tool to detect the races in OpenMP programs monitors a serial execution of the program, but unfortunately cannot guarantee to verify the existence of races even in the programs only with the directives. This paper presents a practical tool which monitors a parallel execution of standard OpenMP program, and not only verifies the existence of races but also detects first races for each shared variable in the programs.
31974930
MPIRace-Check: Detection of Message Races in MPI Programs
Message races, which can cause nondeterministic executions of a parallel program, should be detected for debugging because nondeterminism makes debugging parallel programs a difficult task. Even though there are some tools to detect message races in MPI programs, they do not provide practical information to locate and debug message races in MPI programs. In this paper, we present an on-the-fly detection tool, which is MPIRace-Check, for debugging MPI programs written in C language. MPIRace-Check detects and reports all race conditions in all processes by checking the concurrency of the communication between processes. Also it reports the message races with some practical information such as the line number of a source code, the processes number, and the channel information which are involved in the races. By providing those information, it lets programmers distinguish of unintended races among the reported races, and lets the programmers know directly where the races occur in a huge source code. In the experiment we will show that MPIRace-Check detects the races using some testing programs as well as the tool is efficient.
11137227
Detecting Unaffected Message Races in Parallel Programs
Detecting unaffected race conditions is important to debugging message-passing programs effectively, because such a message race can affect other races to occur or not. Unfortunately, the previous technique to efficiently detect unaffected races does not guarantee that all of the detected races are unaffected. This paper presents a novel technique that manages the states of the detected races by examining if every received message is affected until the execution terminates. Our technique guarantees to efficiently detect unaffected races, because it maintains affects-relations of the races all along the execution of program.
11262890
Locating the Optic Disc in Retinal Images
We present a method to automatically outline the optic disc in a retinal image. Our method for finding the optic disc is based on the properties of the optic disc using simple image processing algorithms which include thresholding, detection of object roundness and circle detection by Hough transformation. Our method is able to recognize the retinal images with general properties and the retinal images with variance of unusual properties since the parameters of our method can be flexibly changed by the unusual properties