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Fixed priority lightweight processes (LWPs) used carelessly can have a dramatic negative effect on the performance of time-sharing LWPs. However, for some applications with strict timing constraints, fixed priority LWPs are the only way to guarantee that the application's requirements are met. Verify that the use of the fixed-priority scheduler is necessary, since for most environments the default time-sharing scheduler provides the best overall system performance.
A bug in a fixed priority program or a malicious fixed priority user can lock out all other processing, including kernel processing. A high-priority fixed priority process can block out all other processing. Users need privilege to create fixed priority processes, and presumably only trustworthy users have this privilege. But you must be aware that the scheduler functions introduce ways to cause trouble and you should be prepared for accidents and for misuse of these functions. Fixed priority processes consume memory that cannot be paged. See ``Process scheduling'' for more information about the system schedulers.