13/07/2018 10:43, Hunt, David: > > On 13/7/2018 9:33 AM, Thomas Monjalon wrote: > > 13/07/2018 10:31, Hunt, David: > >> Hi Thomas, > >> > >> On 12/7/2018 8:09 PM, Thomas Monjalon wrote: > >>> 26/06/2018 11:23, David Hunt: > >>>> This patch set adds the capability to do out-of-band power > >>>> monitoring on a system. It uses a thread to monitor the branch > >>>> counters in the targeted cores, and calculates the branch ratio > >>>> if the running code. > >>>> > >>>> If the branch ratop is low (0.01), then > >>>> the code is most likely running in a tight poll loop and doing > >>>> nothing, i.e. receiving no packets. In this case we scale down > >>>> the frequency of that core. > >>>> > >>>> If the branch ratio is higher (>0.01), then it is likely that > >>>> the code is receiving and processing packets. In this case, we > >>>> scale up the frequency of that core. > >>>> > >>>> The cpu counters are read via /dev/cpu/x/msr, so requires the > >>>> msr kernel module to be loaded. Because this method is used, > >>>> the patch set is implemented with one file for x86 systems, and > >>>> another for non-x86 systems, with conditional compilation in > >>>> the Makefile. The non-x86 functions are stubs, and do not > >>>> currently implement any functionality. > >>>> > >>>> The vm_power_manager app has been modified to take a new parameter > >>>> --core-list or -l > >>>> which takes a list of cores in a comma-separated list format, > >>>> e.g. 1,3,5-7,9, which resolvest to a core list of 1,3,5,6,7,9 > >>>> These cores will then be enabled for oob monitoring. When the > >>>> OOB monitoring thread starts, it reads the branch hits/miss > >>>> counters of each monitored core, and scales up/down accordingly. > >>> It looks to be a feature which could be integrated in DPDK libs. > >>> Why choosing to implement it fully in an example? > >> I needed to set up a thread that looped tightly (~100uS interval) and > >> run it on it's > >> own core. From what I have seen in other cases, it is usually the > >> application that > >> allocates cores and decides what to run on them. I did think about putting > >> some of it in a library, but for this case I thought it made more sense > >> to keep > >> it purely as a sample app. > > I feel some code deserves to be in a library. > > For instance, having different implementations per CPU is a good reason > > to make a library. > > > > Sure, I can look at moving some of the code into the library in a future > release. However, I > believe it's OK as it is for the current merge window.
I will to pull it in 18.08-rc2 if compilation is fine.
