Get a rough idea of the workload distribution per database

perf-db-cpu-workload.sql

WITH cte AS
(
	SELECT DB_NAME(t.[dbid]) AS [Database Name],
	qs.total_worker_time AS [Total Worker Time],
	qs.min_worker_time AS [Min Worker Time],
	qs.total_worker_time/qs.execution_count AS [Avg Worker Time],
	qs.execution_count AS [Execution Count]--, 
	FROM sys.dm_exec_query_stats AS qs WITH (NOLOCK)
	CROSS APPLY sys.dm_exec_sql_text(plan_handle) AS t 
)
SELECT	[Database Name]
,	SUM([Total Worker Time]) AS [Total Worker Time]
,	1. * SUM([Total Worker Time]) / (SELECT SUM(cte.[Total Worker Time]) FROM cte) * 100 AS [Worker Time Percentage]
,	SUM([Execution Count]) AS [Total Execution Count]
,	1. * SUM([Execution Count]) / (SELECT SUM(cte.[Execution Count]) FROM cte) * 100 AS [Execution Count Percentage]
FROM	cte
GROUP BY [Database Name]
ORDER BY 2 DESC OPTION (RECOMPILE);