On Tue, 15 Jun 2021 at 10:55, Alexander Kanavin <alex.kanavin@... <mailto:alex.kanavin@...>> wrote: On Tue, 15 Jun 2021 at 10:48, Richard Purdie <richard.purdie@... <mailto:richard.purdie@...>> wrote: I appreciate the desire simply to delete/disable anything that causes issues but in this case I draw the line and my answer is no. It works fine in the vast majority of usage. But where are the benchmarks that show it's actually beneficial? And commitment from someone to maintain it and address open issues (there are more than just this one)? I went ahead and ran some quick benchmarks myself. Specifically: 1. Running 'free' after things have settled down at boot: a) without prelink core-image-sato-sdk total used free shared buff/cache available Mem: 489352 152104 236284 472 100964 323824 core-image-ptest-fast total used free shared buff/cache available Mem: 1004680 43456 927688 256 33536 941156 b) with prelink core-image-sato-sdk total used free shared buff/cache available Mem: 489352 153048 235544 468 100760 322900 core-image-ptest-fast total used free shared buff/cache available Mem: 1004680 44444 928128 256 32108 940168 2. Running -c testimage a) without prelink core-image-sato-sdk () - Ran 66 tests in 96.693s core-image-sato-sdk () - Ran 66 tests in 96.469s core-image-sato-sdk () - Ran 66 tests in 94.994s core-image-ptest-fast () - Ran 66 tests in 583.767s core-image-ptest-fast () - Ran 66 tests in 576.564s core-image-ptest-fast () - Ran 66 tests in 576.797s b) with prelink core-image-sato-sdk () - Ran 66 tests in 96.390s core-image-sato-sdk () - Ran 66 tests in 96.615s core-image-sato-sdk () - Ran 66 tests in 95.596s core-image-ptest-fast () - Ran 66 tests in 576.248s core-image-ptest-fast () - Ran 66 tests in 574.618s core-image-ptest-fast () - Ran 66 tests in 576.760s
I think the advantage is not on high end CPUs but more on less powerful ones, so perhaps trying it on something like rpi0 or lower would be good
So the memory usage is actually *better* without prelink. And any timing benefits are lost in statistical noise, in these tests at least. So I do not think it is wrong to question the usefulness of this feature. I'd like to hear Mark's take on this, as prelink-cross is primarily his work, he's put a lot of effort into it, and I would want to know where the benefits are. Note that Red Hat abandoned prelink in 2013, and prelink-cross likewise hasn't seen any commits for two years.
