Counters Frequency and costs

D. Nahuel C. 

You can see how much data a counter used in 10s, 30s etc...

Perf
| where CounterName == "% Processor Time" and  InstanceName == "_Total" 
| summarize TotalGBytes = sum(_BilledSize / (1024*1024*1024)) by bin(TimeGenerated, 10s) 

Go to Log Analytics and Run Query

I have a few posts along similar lines: https://cloudblogs.microsoft.com/industry-blog/en-gb/cross-industry/2019/07/22/azure-log-analytics-looking-at-data-and-costs-part-4/ 

You might need to see Bytes, to find the average per time period

Perf
| where CounterName == "% Processor Time" and  InstanceName == "_Total" 
| summarize TotalBytes = avg(_BilledSize) by bin(TimeGenerated, 10s) 

Results: