Hello. On Thu, Sep 05, 2024 at 01:41:27PM GMT, Chen Ridong <chenridong@xxxxxxxxxx> wrote: > We optimized the freezer to reduce redundant loops. We add a selftest to > ensure our optimizations cause no harm, and we confirmed that the > performance can be improved. I think these patches have potential to make the code also cleaner and better to understand (the numbers from optimization don't impress me that much at the moment). I post more comments on the individual patches. > We tested the following subtree: D, E, F and G each have n children. > A > / \ > B C > / | \ \ > D E F G > / | \ \ > 1-n 1-n 1-n 0-n (Why is the last one different?) > Our test is to freeze A B C D E F G, and then unfreeze A B C D E F G. I would say measuring freezing/unfreezing of only A would give better idea about the impact of the change. (Going through all descendants manually would unfairly show greater improvement.) > We measured the elapsed time. > > BEFORE(ns) AFTER(ns) SAVED(ns) > n=10 142679950 139666014 3,013,936 > n=100 199832160 192773032 7,059,128 > n=1000 488595100 414901570 73,693,530 How many tasks were there inside cgroups in this benchmark? (I assume in practice the freezing time would be dominated by waiting for tasks' response, so it'd be good to note this beside this result.) Thanks, Michal
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