On Mon 2023-01-09 16:12:53, Luis Chamberlain wrote: > On Mon, Jan 09, 2023 at 02:40:27PM +0100, Petr Mladek wrote: > > Why are try hardly comparable? > > > > 1. The speed depends on the number of loaded modules > > and number of symbols. It highly depends on the configuration > > that was used to build the kernel. > > > > 2. The test runs only once. As a result it is hard to judge > > how big is the noise. > > > > 3. The noise might depend on the size and state of CPU caches. > > > > > > I personally vote for removing this selftest! > > Even so, just as with testing a filesystem with different types of > configurations, at least testing a few configs helps and it's what > we do. Then, if anyone ever wanted to try to increase performance > on symbol lookup today they have no easy way to measure things. How > would they go about comparing things performance without this selftest? How many people cares about kallsyms performance, please? Is it worth spending time one implementing and maintaining such a selftest? Yes, Zhen wanted to make it faster. But how likely will anyone else try to make it even better? Do we need to spend time on this in the meantime? > This selftests helps generically with that *and* helps peg on to it any sanity > checks you may wish to add to those APIs which we just don't want to do > upstream. >From my POV, it would be much more important to check if the API works as expected. I mean that it gives the right results. I am not sure that performance is that important to spend more time on this one. Also I am not sure if selftests are the right location for performance tests. My understanding is that it is a framework for functional testing. It is showing if the tests passed or not. But performance tests do not give "pass or not" results. Best Regards, Petr
