[Sorry, adding back the CC list] On Mon, Aug 8, 2022 at 11:45 PM Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> wrote: > > This is required to prevent callbacks triggering RCU machinery too > quickly and too often, which adds more power to the system. > > When testing, we found that these paths were invoked often when the > system is not doing anything (screen is ON but otherwise idle). Unfortunately, I am seeing a slow down in ChromeOS boot performance after applying this particular patch. It is the first time I could test ChromeOS boot times with the series since it was hard to find a ChromeOS device that runs the upstream kernel. Anyway, Vlad, Neeraj, do you guys also see slower boot times with this patch? I wonder if the issue is with wake up interaction with the nocb GP threads. We ought to disable lazy RCU during boot since it would have little benefit anyway. But I am also concerned about some deeper problem I did not catch before. I'll look into tracing the fs paths to see if I can narrow down what's causing it. Will also try a newer kernel, I am currently testing on 5.19-rc4. Thanks, - Joel
