> Le 21 juin 2023 à 21:39, Mark Wielaard <m...@klomp.org> a écrit : > > > Hi Romain, > > That patch looks good. It should reduce the number of calls to > elf_getdata_rawchunk a lot. Making it less urgent that function is > fast. But if you could test it that would be appreciated. I'll also > test it a bit more and will probably merge it if no issues show up > since it does seem better than keep using the linear list. > > Thanks, > > Mark
Hi, So I have done some testing, running the command: [root@fa28b3d254fd systemd]# rm -rf /var/lib/systemd/coredump/* && journalctl --flush --rotate && journalctl --vacuum-time=1s && time cat the-core | build/systemd-coredump $$ 0 0 11 1687360485 1000000000000000 localhost && journalctl Where "the-core" is our real core dump we had in production, with around 1700+ shared libraries loaded, and the uncompressed core dump size is 2GB+. Without the systemd patch, without the elfutils patch. real 3m42.308s user 3m39.579s sys 0m2.294s Without the systemd patch, with the elfutils patch (3 runs, first one excluded to make sure the kernel caches what it caches): real 0m15.543s user 0m13.662s sys 0m2.405s real 0m15.976s user 0m13.832s sys 0m2.481s real 0m15.612s user 0m13.687s sys 0m2.470s With the systemd patch, without the elf utils patch (3 runs, first one excluded to make sure the kernel caches what it caches): real 0m2.994s user 0m1.104s sys 0m2.477s real 0m3.011s user 0m1.154s sys 0m2.447s real 0m3.009s user 0m1.141s sys 0m2.457s With the systemd patch, with the elf utils patch (3 runs, first one excluded to make sure the kernel caches what it caches): real 0m2.921s user 0m1.093s sys 0m2.399s real 0m2.950s user 0m1.129s sys 0m2.401s real 0m2.933s user 0m1.136s sys 0m2.371s Overall we can see that both fix independently fix the performance issue (yet the systemd patch seems a bit more effective), so I guess both fixes are welcome. Mark, do you think it's worth backporting this in CentOS Steam 9/RHEL 9 on elfutils side ? If you need a ticket, we have Red Hat case 03536980 which lead to RHBZ 2215412. Thanks ! Romain
