Linux Test Project

Next Generation Posix Threads

Verification Summary Report


This document describes the methods used by the IBM Linux Technology Center Test Team to perform verification on Next Generation Posix Threads. For more information about the LTC Test Team, see For More information about NGPT, see

Test Environment

This section describes the hardware and software environments used in testing NGPT.

Name Processor Memory
Up1 PIII-866 256Mb
Up2 PIII-866 256Mb
Smp1 (4)PIII-700 2Gb


Unresolved Issues

There is a load balancing issue that randomly appears in SMP environments. In some situations, load may not be evenly balanced among kernel threads, or a hang may occur with all threads stuck in do_select. This issue is being addressed by the NGPT development team.

Further Testing

Test Cases


NGPT was very stable on single processor machines. A problem was found in early testing where any test that used pthread_create() would generate a segmentation fault when a call to exit() was made. This issue has already been corrected before the 1.0 release. A minor problem was discovered with Test_mp that prevented the test from running. In this test, and many others, pth_init() was used, but in Test_mp, the return value was checked. The pth_init() function is no longer needed and returns a failed value. This function was removed from all the testcases that used it without any loss of function. This change was also made prior to the final 1.0 release. There is still an unresolved issue where tests will hang in do_select on smp. This issue is being addressed by the NGPT development team.

Test team:

Paul Larson  Last modified on: June 15, 2006 - 16:29:46 UTC.