On Wed, Jun 05, 2019 at 01:16:46PM -0700, Linus Torvalds wrote: > On Wed, Jun 5, 2019 at 6:49 AM Jan Glauber <jglau...@cavium.com> wrote: > > > > Add an upper bound to the loop to force the fallback to spinlocks > > after some time. A retry value of 100 should not impact any hardware > > that does not have this issue. > > > > With the retry limit the performance of an open-close testcase > > improved between 60-70% on ThunderX2. > > Btw, did you do any kind of performance analysis across different > retry limit values?
I tried 15/50/100/200/500, results were largely identical up to 100. For SMT=4 a higher retry value might be better, but unless we can add a sysctl value 100 looked like a good compromise to me. --Jan > I'm perfectly happy to just pick a random number and '100' looks fine > to me, so this is mainly out of curiosity. > > Linus