Hi guys Recently I have been playing around with redhat kernel (Red Hat Enterprise Linux Server release 7.2 (Maipo)) params a bit to look out for kernel level optimisations. One such optimisation is not allowing processes to go into C state which can be done by grub boot params *intel_idle.max_cstate=0 processor.max_cstate=0 idle=poll* OR * /usr/libexec/tuned/pmqos-static.py cpu_dma_latency=0*. I am a bit confused as to which one to use and what to expect.
I read this wonderful blog post http://www.breakage.org/2012/11/14/processor-max_cstate-intel_idle-max_cstate-and-devcpu_dma_latency/. Here Jeremy has mentioned in Test #6 that with /dev/cpu_dma_latency=0 and intel_idle.max_cstate=0, cmdline overrides /dev/cpu_dma_latency and cpu will be in c1 state for 99.99% of the time. However, when I recreated this on my server I am seeing the cpus in c0 (Busy state) 100% of the time. I am a bit confused as to why I am getting different results. What would be the preferrable way to keep cores in c0 (Busy state) 100% of the time using minimal kernel tweaking? Thanks Himanshu Sharma -- You received this message because you are subscribed to the Google Groups "mechanical-sympathy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
