Method and apparatus for detecting memory leaks in computer systems
A system that identifies processes with a memory leak in a computer system. During operation, the system periodically samples memory usage for processes running on the computer system. The system then ranks the processes by memory usage and selects a specified number of processes with highest memory usage based on the ranking. For each selected process, the system computes a first-order difference of memory usage by taking a difference between the memory usage at a current sampling time and the memory usage at an immediately preceding sampling time. The system then generates a memory-leak index based on the first-order difference and a preceding memory-leak index computed at the immediately preceding sampling time.
1. A method for identifying processes with a memory leak in a computer system, comprising:
for each process that is being monitored,
computing a first-order difference of memory usage by taking a difference between the memory usage at a current sampling time and the memory usage at an immediately preceding sampling time; and
generating a memory-leak index based on the first-order difference and historical memory-usage information, wherein generating the memory-leak index involves waiting until the process is past an initial blackout period, wherein the process is past the initial blackout period if a minimum run-time for the process has elapsed, and if a minimum number of memory usage samples have been taken.
2. The method of claim 1 , wherein prior to monitoring memory usage, the method further comprises selecting processes to be monitored by:
periodically sampling memory usage for processes running on the computer system;
ranking the processes by memory usage; and
selecting for monitoring a specified number of processes with highest memory usage based on the ranking.
3. The method of claim 1 , wherein the historical memory-usage information includes a preceding memory-leak index computed at the immediately preceding sampling time.
4. The method of claim 1 , wherein the method further comprises:
sorting the processes by decreasing order of memory-leak index; and
reporting a specified number of top processes with non-negative memory-leak indexes.
5. The method of claim 1 , wherein generating the memory-leak index involves applying an exponential forgetting function to the first-order difference and the memory-leak index.
6. The method of claim 5 , wherein a parameter is used to specify the extent to which the exponential forgetting function discards past memory usage values.
7. The method of claim 6 ,
wherein a larger value for the parameter causes the exponential forgetting function to discard past memory usage values more quickly; and
wherein a smaller value for the parameter causes the exponential forgetting function to discard past memory usage values more slowly.
8. The method of claim 1 ,
wherein the memory-leak index is proportional to the magnitude of the memory leak; and
wherein a process with a high memory-leak index indicates that the process is likely to suffer from memory leaks.
9. An apparatus for identifying processes with a memory leak in a computer system, comprising:
a memory; and
a memory-leak detection mechanism;
wherein the memory-leak detection mechanism is configured to:
for each process that is being monitored, to
compute a first-order difference of memory usage by taking a difference between the memory usage at a current sampling time and the memory usage at an immediately preceding sampling time; and to
generate a memory-leak index based on the first-order difference and historical memory-usage information, wherein generating the memory-leak index involves waiting until the process is past an initial blackout period, wherein the process is past the initial blackout period if a minimum run-time for the process has elapsed, and if a minimum number of memory usage samples have been take.
10. The apparatus of claim 9 , wherein prior to monitoring memory usage, to select processes to be monitored, the memory-leak detection mechanism is configured to:
periodically sample memory usage for processes running on the computer system;
rank the processes by memory usage; and
select for monitoring a specified number of processes with highest memory usage based on the ranking.
11. The method of claim 9 , wherein the historical memory-usage information includes a preceding memory-leak index computed at the immediately preceding sampling time.
12. The apparatus of claim 9 , wherein the memory-leak detection mechanism is additionally configured to:
sort the processes by decreasing order of memory-leak index; and to
report a specified number of top processes with non-negative memory-leak indexes.
13. The apparatus of claim 9 , wherein while generating the memory-leak index, the memory-leak detection mechanism is configured to apply an exponential forgetting function to the first-order difference and the memory-leak index.
14. The apparatus of claim 13 , wherein a parameter is used to specify the extent to which the exponential forgetting function discards past memory usage values.
15. The apparatus of claim 14 ,
wherein a larger value for the parameter causes the exponential forgetting function to discard past memory usage values more quickly; and
wherein a smaller value for the parameter causes the exponential forgetting function to discard past memory usage values more slowly.
16. The apparatus of claim 9 ,
wherein the memory-leak index is proportional to the magnitude of the memory leak; and
wherein a process with a high memory-leak index indicates that the process is likely to suffer from memory leaks.
17. A computer system for identifying processes with a memory leak, comprising:
a memory; and
a memory-leak detection mechanism;
wherein the memory-leak detection mechanism is configured to:
for each process that is being monitored, to
compute a first-order difference of memory usage by taking a difference between the memory usage at a current sampling time and the memory usage at an immediately preceding sampling time; and to
generate a memory-leak index based on the first-order difference and historical memory-usage information, wherein generating the memory-leak index involves waiting until the process is past an initial blackout period, wherein the process is past the initial blackout period if a minimum run-time for the process has elapsed, and if a minimum number of memory usage samples have been taken.
18. The computer system of claim 17 , wherein prior to monitoring memory usage, to select processes to be monitored, the memory-leak detection mechanism is configured to:
periodically sample memory usage for processes running on the computer system;
rank the processes by memory usage; and
select for monitoring a specified number of processes with highest memory usage based on the ranking.
19. The computer system of claim 17 , wherein the historical memory-usage information includes a preceding memory-leak index computed at the immediately preceding sampling time.