6 ms·
Are you familiar with "vmstat -z"? It will show you any kernel limit that was hit under the "FAIL" column. When you know what is happening/failing its much easi
by rwaksmunski 5y ago
Are you familiar with "vmstat -z"? It will show you any kernel limit that was hit under the "FAIL" column. When you know what is happening/failing its much easier to tune and scale. dtrace is also invaluable for this.
- toast0 5y agoNo I wasn't, that's quite nice, thanks. At work, we had tools to look at selected vm stats, but a fuller pictures is nice, and I don't have access to the tools I did anyway. The fail column of course only applies to explicit limits; not things like doing task X requires lock Y, so if you're doing X a lot on a 56-thread machine, you can only do it so much before lock contention grinds you to a halt. (OTOH, top usually shows what lock you're waiting on, so it's pretty easy to track from there, and I know there are better lock debugging tools, I've just never needed them because either the lock is blindingly obvious and I can work on it, or it's kind of subtle and the other fixer knows how to use the tools for subtle problems :)