On Mon, Jan 29, 2024 at 05:47:39PM +0000, Joel Fernandes wrote: > Hi Guys, > Something caught my eye in [1] which a colleague pointed me to > - CONFIG_HZ=1000 : 14866.05 bogo ops/s > - CONFIG_HZ=1000+nohz_full : 18505.52 bogo ops/s > > The test in concern is: > stress-ng --matrix $(getconf _NPROCESSORS_ONLN) --timeout 5m --metrics-brief > > which is a CPU intensive test. > > Any thoughts on what else can attribute a 30% performance increase > versus non-nohz_full ? (Confession: No idea if the baseline is > nohz_idle or no nohz at all). If it is 30%, I may want to evaluate > nohz_full on some of our limited-CPU devices :) > Timer overhead and its scheduler-callback? If i do not mess something the NO_HZ_FULL will disable the timer if there is only one task on CPU so that running task benefits from not being interrupted thus gets more CPU time. -- Uladzislau Rezki
