On Wed, Apr 05, 2023 at 04:43:14PM -0300, Marcelo Tosatti wrote: > Two points: > > 1) For a virtualized system, the overhead is not only of executing the > IPI but: > > VM-exit > run VM-exit code in host > handle IPI > run VM-entry code in host > VM-entry
I thought we could do IPIs without VMexit these days? Also virt... /me walks away. > 2) Depends on the application and the definition of "occasional". > > For certain types of applications (for example PLC software or > RAN processing), upon occurrence of an event, it is necessary to > complete a certain task in a maximum amount of time (deadline). If the application is properly NOHZ_FULL and never does a kernel entry, it will never get that IPI. If it is a pile of shit and does kernel entries while it pretends to be NOHZ_FULL it gets to keep the pieces and no amount of crying will get me to care.
