IIRC JIRA used to ignore profile entries which took less than 5ms to execute. In JIRA 3.0.3 it doesn't, which results in extremely long profile logs:

[29557ms] - /jira/secure/IssueNavigator.jspa
[28074ms] - IssueNavigator.execute()
[27760ms] - IssueManager.execute()
[27759ms] - Searching Issues
[1597ms] - Lucene Query
[13ms] - Permission Query
[32ms] - Lucene Search
[5626ms] - Retrieve From cache/db and filter
[1ms] - IssueManager.getIssue()
[0ms] - IssueManager.getIssue()
[0ms] - IssueManager.getIssue()
[1ms] - IssueManager.getIssue()
[0ms] - IssueManager.getIssue()
[0ms] - IssueManager.getIssue()
[0ms] - IssueManager.getIssue()
[0ms] - IssueManager.getIssue()
[1ms] - IssueManager.getIssue()
....