Have you tried testing with Jitter? Looking through the CSIT data, will give an idea of the reasonable ranges for results.
Intel ICELAKE https://docs.fd.io/csit/master/report/introduction/test_environment_sut_calib_icx.html Intel CASCADE LAKE https://docs.fd.io/csit/master/report/introduction/test_environment_sut_calib_clx.html Ray K -----Original Message----- From: Antonio Di Bacco <a.dibacco...@gmail.com> Sent: Friday 24 June 2022 10:45 To: Stephen Hemminger <step...@networkplumber.org> Cc: users@dpdk.org Subject: Re: Large interruptions for EAL thread running on isol core Thank you, didn't know that "System management units" could steal CPU!!! That is scary On Thu, Jun 23, 2022 at 8:42 PM Stephen Hemminger <step...@networkplumber.org> wrote: > > On Thu, 23 Jun 2022 20:03:02 +0200 > Antonio Di Bacco <a.dibacco...@gmail.com> wrote: > > > I'm running a DPDK thread on an isolated core. I also set some > > flags that could help keeping the core at rest on linux like: > > nosoftlockup nohz_full rcu_nocbs irqaffinity. > > > > Unfortunately the thread gets some interruptions that stop the > > thread for about 20-30 micro seconds. This seems smal but my > > application suffers a lot. > > > > I also tried to use rte_thread_set_priority that indeed has a > > strong effect but unfortunately creates problems to Linux (like > > network not working). > > > > Is there any other knob that could help running the DPDK thread with > > minimum or no interruptions at all? > > Look with perf and see what is happening. > First check for interrupt affinity. > Don't try real time priority. > > The other thing to look for would be any BIOS settings. > Some system management units can take away CPU silently for polling > some internal housekeeping.
