Hi Bill, Bill.Holler <> wrote:
> Hi Aubrey, > > We are wondering if in the long term the Intel Energy > Performance Bias MSR could be set dynamically? > For example we would like to set the MSR for more > power savings when the system is mostly idle. You may find the SPECPower data in the previous mails we discussed offline. Please let me know if you need it, I can send again. >From the SPECPower data, the idle power is the same no matter what the policy(MSR value) is. So, IMHO the only value is, if the user doesn't care about power but only needs performance, we can change the policy to perf-bias and if the user needs best perf/power tradeoff, we can set the policy to balanced. The MSR setting doesn't help to save power in idle. Did I catch your point? > We also might want to specify different settings for > example on a priority Solaris Container (Zone) bound to > a processor set. This is an interesting topic. We probably need to offer another interface to set the per-cpu policy. Fortunately, the hardware supports this requirement. it is a per logical cpu MSR. > > What is the latency for setting Intel Energy Performance > Bias MSR? Are there stability issues with rapidly setting > the MSR? > > Thank you, > Bill This MSR works exactly the same as the pstate MSR - IA32_PERF_CTL_MSR, you can write and forget it. I didn't see any report of stability issues so far. Thanks, -Aubrey
