3 ms·

I have been complaining about journald abysmal performances for almost as long as I can remember. Here is my latest documented benchmark from 2023, which was sl

• marginalia_nu 2mo ago
  I'm no fan of journald, but I have some methodological issues with this test. The reads from /tmp/all.log are almost certainly cached since you just wrote the file, and will basically boil down to a memcpy call, rather than actual disk I/O. Speed difference isn't as big as you would think on a modern SSD, but it isn't nothing either. Running this between calls should flush the changes to disk and then drop the page cache, making for a fairer test. $ sudo sync $ echo 3 | sudo tee /proc/sys/vm/drop_caches
  • soneil 2mo ago
    I tried similar. Each command looped 5 times, ignore the best and worst times, and average the mean three. journalctl >/tmp/all.log 0m59.763s journalctl | grep -c sshd 0m57.767s (otherwise >all is the only example encumbered by write speeds) wc -l /tmp/all.log 0m0.336s grep -c sshd /tmp/all.log 0m1.776s
    • otterley 2mo ago
      You didn't use the query feature of journalctl, so you basically had it do an entire table conversion. Of course that's not going to show its performance value. This is what you should be running for a proper comparison: 1. `echo 3 | sudo tee /proc/sys/vm/drop_caches` 2. `time journalctl -u ssh.service >/dev/null` 3. `journalctl >/tmp/all.log` 4. `echo 3 | sudo tee /proc/sys/vm/drop_caches` 5. `time grep -q sshd /tmp/all.log`