> On Mar 8, 2023, at 7:01 AM, Frederic Weisbecker <frederic@xxxxxxxxxx> wrote: > > On Wed, Mar 08, 2023 at 05:52:50AM -0800, Joel Fernandes wrote: >> Just to add to previous reply: >> >> One thing to consider is that it is more of a performance improvement for >> booting in expedited mode to fallback to normal later, than a bug >> fix. Repeated synchronize_rcu() can easily add 100s of milliseconds and to >> remedy that — a conversion of the call from normal API to the expedited API >> will not help. > > 2 things to consider: > > 1) Is it this about specific calls to synchronize_rcu() that repeat a lot > and thus create such measurable impact? If so the specific callsites should > be considered for a conversion. > > 2) Is it about lots of different calls to synchronize_rcu() that gather a big > noise? Then the solution is different. > > Again without proper analysis, what do we know? Again, no one disputed that proper analysis is needed. That is obvious. I was just responding to your assumption that if boot is slow, user space will also be slow. That is not a good thing to conclude because there are many factors. Slowness at boot may be considered a bug, but slowness after boot may not be (say if the user care mores for power later). On my side I am planning to dig deeper into our boot process, but it will take time. I hope Qiuxu can do the boot analysis on his side. Thanks. > > Thanks.
