On 2023/1/10 17:57, Petr Mladek wrote: > 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. I think both of you have a point. In the absence of a better way to improve it, perhaps deleting the performance test is the best option now. OK, I'll do this first. > > Best Regards, > Petr > . > -- Regards, Zhen Lei
