Storage medium storing performance degradation cause estimation program, performance degradation cause estimating device, and performance degradation cause estimation method

A performance degradation cause estimating device comprising:

• a memory;
• and
• a processor coupled to the memory and configured to execute a process including
• calculating, by referencing the memory storing response times for accesses of multiple access types and for each of the access types, first access densities in respective time periods obtained by dividing a first time period by a first time length, wherein the first access densities are obtained by multiplying the numbers of appearances of the access type in the time periods by a minimum response time for the access type;
• calculating, based on the calculated first access densities, first variation coefficients of the first access densities in respective time periods obtained by dividing the first time period by a second time length that is longer than the first time length, for each of the access types;
• calculating, by referencing the memory and for each of the access types, second access densities in respective time periods obtained by dividing a second time period, different from the first time period and identified as a time period in which a response time for the access increases, by a third time length, wherein the second access densities are obtained by multiplying the numbers of appearances of the access type in the respective time periods obtained by dividing the second time period by the third time length by a minimum response time for the access type in the second time period;
• calculating, based on the calculated second access densities, second variation coefficients of access densities in respective time periods obtained by dividing the second time period by a fourth time length that is longer than the third time length;
• and
• identifying a cause of the increase in the response time within the second time period based on the result of a test of goodness of fit of a distribution of the first variation coefficients and a distribution of the second variation coefficients.

A performance degradation cause estimation method that causes a computer to execute a process, the process comprising:

• Calculating, by referencing a memory storing response times for accesses of multiple access types and for each of the access types, first access densities in respective time periods obtained by dividing a first time period by a first time length, wherein the first access densities are obtained by multiplying the numbers of appearances of the access type in the respective time periods by a minimum response time for the access type;
• calculating, based on the calculated first access densities, first variation coefficients of the first access densities in respective time periods obtained by dividing the first time period by a second time length that is longer than the first time length, for each of the access types;
• calculating, by referencing the memory and for each of the access types, second access densities in respective time periods obtained by dividing a second time period, different from the first time period and identified as a time period in which a response time for the access increases, by a third time length, wherein the second access densities are obtained by multiplying the numbers of appearances of the access type in the respective time periods obtained by dividing the second time period by the third time length by a minimum response time for the access type in the second time period;
• calculating, based on the calculated second access densities, second variation coefficients of the second access densities in respective time periods obtained by dividing the second time period by a fourth time length that is longer than the third time length;
• and
• identifying a cause of the increase in the response time within the second time period based on the result of a test of goodness of fit of a distributions of the first and the second variation coefficients.