Hi, During the development of "unSPEC" [1] benchmarking suite, I made some interesting observations regarding prelink. - Here are some measurements (for LibreOffice [2] loading time in seconds) done using the "unSPEC" bench-marking suite. These numbers are repeatable and you are encouraged to try "unSPEC" to do independent validation of these numbers. - hkario (modern SSD based system, cache flushed): (1.816, 1.811, 1.797, 1.827 with prelink), (2.034, 2.042, 2.027, 2.016 without prelink) - hkario (modern SSD based system, cache intact): (2.155, 2.121, 2.101, 2.299 with prelink), (2.311, 2.052, 2.047, 2.037 without prelink) - halfie (T430s): (10.725, 10.095, 10.378, 10.568 with prelink), (8.901, 8.993, 9.075, 9.448, 9.489 without prelink) - danpb (T530): I see basically no measurable difference in times with or without prelink - quite a lot of variation, but all in same ballpark, (8.374, 7.849, 8.457, 7.673, 7.608, 8.031, 8.350, 8.183, 7.381 with prelink), (7.366, 8.009, 7.500, 7.949, 8.208, 8.351, 7.849, without prelink). - For building kernels (using the "kernel-bench" [3] component of unSPEC suite), prelink saved <= 250 ms over the non-prelink environment (which took 1m19.138s). hkario even reports worse performance numbers for the prelink environment. Additionally, we have specialized softwares like ccache and distcc to solve long-compilation-time problems. In short, we could not distinguish the performance gains of prelink over the "background noise" in many (or even most) cases. So, I was wondering if you are aware of any use-cases where prelink provides measurable benefits. It would be awesome if you could run unSPEC on your systems and report back the numbers. unSPEC is easy to use and doesn't take much time (or steps) to run. For more information, please see the following links. References: [1] https://github.com/kholia/unSPEC [2] https://github.com/kholia/unSPEC/tree/master/LibreOffice [3] https://github.com/kholia/unSPEC/tree/master/kernel-bench -- Dhiru -- security mailing list security(a)lists.fedoraproject.org https://admin.fedoraproject.org/mailman/listinfo/security

----- Original Message ----- > > All very well and nice, but what does this have to do with the Security > List ? > > Also, most people will switch off pre-linking on servers, due to > erroneous reports of lib and binary changes, that are caused by pre-linking. > I told Dhiru we should start with this list because if we disable prelink, we get ASLR support for many things. I *suspect* prelink isn't giving us much gain anymore, but it will be helpful to see what others think, and what they see. Thanks.