NPTL (Native POSIX Threading Library) Tests and Trace

 Test Campaign #2

Document	Test Campaign 2 and Final Report
Date	Nov 22, 2005
Author	Sébastien DECUGIS
Link	Full document
Outlines	This report is built as a HOWTO on Testing a POSIX Implementation. It describes all the tools we have built or used during our project, and explains how to use these tools. It also gives the analysis of our second (and final) test campaign results. It finally summarizes the history of our project, with the key events.

 Ottawa Linux Symposium

Document	Ottawa Linux Symposium paper and presentation
Date	Jul 23, 2005
Authors	Sébastien DECUGIS and Tony REIX
Links	Paper (pdf) Presentation (openoffice2)
Outlines	This content was written for the Ottawa Linux Symposium 2005 event. It shows almost all parts of our project, and the presentation can give a good idea of our work.

 Test Campaign #1

Document	Test Campaign 1 Final Report
Date	Nov 16, 2004
Author	Sébastien DECUGIS
Link	Full document
Conclusions	Ensure that the tests are bug-free and can execute on different hardware and software. This first goal has been partly fulfilled. In each run, at least 5 testcases are killed with a segmentation fault. This may be due to bugs in the system or in the tests themselves. Further analysis is needed here. Nevertheless, no unexpected problem was found in the 15 functions from our priority-1 list. Check the NPTL bugs, in several situations:  - bleeding-edge context, with vanilla kernel and glibc; or standard OS distributions  - with large machines (many CPUs, many I/O, lot of memory)  - with several CPU architectures (i686, Power-PC, Itanium 2) The second goal was distrurbed by the fact that a lot of POSIX functionnalities have been recently added to the Linux kernel and to glibc (message queues for example), and most of the tested distributions are older than these additions -- and therefore a lot of header and execution problems appeared with those routines. It is also worth to notice that it was not possible to compile the library for Power-PC linux (as the binutils package failed to install), and that the process was far less straight-forward on Itanium-2 than on i686 (needed to add some links, etc...). On the other hand, the NPTL behaved very well on large machines, showing no scalability weakness. Build a status on NPTL on main distributions, on the same machine (i686).  - Suse Linux Entreprise Server 9 (SLES9)  - RedHat Fedora Core 3 (test 2)  - RHEL3 (updated with NPTL support and recent kernel) The conclusion for the third goal is that the more recent the distribution components (kernel, glibc), the better the results. Indeed, this is due to the NPTL being still under heavy development, with changes almost everyday; so a two-months delay between two Linux distributions leads to a large difference in results. It is worth noting anyway that all the tested distributions have this header problem that prevented most of the scalability tests to be run; even if their NPTL binary file contains the functionnality. This is due to NPTL-only routines being unusable in default environment -- one need special linker flags to be able to use it (actually tests are linked to linuxthreads library at compilation time).

 Other (older) Documents

• Testing.
  • An analysis of the coverage, at the start of the project. This is quite a big document, almost unusable. It contains a brief description of every tests from the OPTS and the NPTL source tree.
  • A partial list of the NPTL files. This list shows which features have common sources for all architectures, and which have architecture-dependant sources. This might result in performance differences, or in different bugs.
  • This is an attempt to show the scalability limits of the NPTL. The process is iterative: each time we encounter a new limit, this document will grow.
• Tracing.
  • v03 of the Trace tool design.
  • The current implementation can be found in sourceforge, with updated documentation.