Re: [BUG] 500-2000% performance regression w/ 5.10
From: Chris Murphy <hidden>
Date: 2021-01-04 01:17:25
The problem is worse on SSD than on HDD. It actually makes the SSD *slower* than an HDD, on 5.10. For this workload HDD 5.9.16-200.fc33.x86_64 mq-deadline kyber [bfq] none $ time tar -xf /tmp/firefox-85.0b4.source.tar.xz && time sync real 1m27.299s user 0m27.294s sys 0m14.134s real 0m8.890s user 0m0.001s sys 0m0.344s ---------------- HDD 5.10.4-200.fc33.x86_64 mq-deadline kyber [bfq] none $ time tar -xf /tmp/firefox-85.0b4.source.tar.xz && time sync real 2m14.936s user 0m54.396s sys 0m47.082s real 0m7.726s user 0m0.001s sys 0m0.382s ==================== SSD, compress=zstd:1 5.9.16-200.fc33.x86_64 [mq-deadline] kyber bfq none $ time tar -xf /tmp/firefox-85.0b4.source.tar.xz && time sync real 0m41.947s user 0m29.359s sys 0m18.088s real 0m2.042s user 0m0.000s sys 0m0.065s ---------------- SSD, compress=zstd:1 5.10.4-200.fc33.x86_64 [mq-deadline] kyber bfq none $ time tar -xf /tmp/firefox-85.0b4.source.tar.xz && time sync real 2m59.581s user 1m4.097s sys 0m56.323s real 0m1.492s user 0m0.000s sys 0m0.077s