On 2018.11.07 09:04 Doug Smythies wrote: > The Phoronix dbench test was run under the option to run all > the tests, instead of just one number of clients. This was done > with a reference/baseline kernel of 4.20-rc1, and also with this > TEO version 3 patch. The tests were also repeated with trace > enabled for 5000 seconds. Idle information and processor > package power were sampled once per minute in all test runs. > > The results are: > http://fast.smythies.com/linux-pm/k420/k420-dbench-teo3.htm > http://fast.smythies.com/linux-pm/k420/histo_compare.htm
Another observation from the data, and for the reference/ baseline 4.20-rc1 kernel, idle state 0 histogram plots is that there are several (280) long idle durations. For unknown reasons, these are consistently dominated by CPU 5 on my system (264 of the 280, in this case). No other test that I have tried shows this issue, But other tests also tend to set the need_resched flag whereas the dbench test doesn't. Older kernels also have the issue. I tried: 4.19, 4.18 4.17, 4.16+"V9" idle re-work patch set of the time. There is no use going back further, because "V9" was to address excessively long durations in shallow idle states. I have not made progress towards determining the root issue. ... Doug
