Cpu% usage alert is not working for 'alert if counter=raises above'
I am only able to get SQL Server 2012 to fire an alert based upon the "Workload Group Stats -> CPU Usage %" if I enable a dummy Resource Governor classifier function that classifies all connections into the default Resource Governor group.

I used the following classifier function, with the associated code to enable that function:

USE master;
GO
CREATE FUNCTION dbo.fnDummyClassifier()
RETURNS sysname
WITH SCHEMABINDING
AS
BEGIN
    RETURN N'default'; --every session is assigned to the "default" pool.
END
GO
ALTER RESOURCE GOVERNOR WITH (CLASSIFIER_FUNCTION = [dbo].[fnDummyClassifier]);
GO
ALTER RESOURCE GOVERNOR RECONFIGURE;
GO


I created an alert using this code, that alerts whenever CPU usage rises above 10%:

EXEC msdb.dbo.sp_add_alert @name=N'CPUUsage' 
        , @enabled=1
        , @delay_between_responses=0
        , @include_event_description_in=1
        , @performance_condition=N'Workload Group Stats|CPU usage %|default|&gt;|0.1'
        , @job_id=N'00000000-0000-0000-0000-000000000000';
GO

EXEC msdb.dbo.sp_add_notification @alert_name=N'CPUUsage'
    , @operator_name=N'Max'
    , @notification_method = 1;
GO


I then used this query to force CPU usage in a session that is connected to SQL Server after the classifier function has been enabled, and the Resource Governor has been reconfigured:

SELECT CRYPT_GEN_RANDOM(10)
FROM (VALUES (0), (1), (2), (3), (4), (5), (6), (7), (8), (9)) v1(num)
    CROSS JOIN (VALUES (0), (1), (2), (3), (4), (5), (6), (7), (8), (9)) v2(num)
    CROSS JOIN (VALUES (0), (1), (2), (3), (4), (5), (6), (7), (8), (9)) v3(num)
    CROSS JOIN (VALUES (0), (1), (2), (3), (4), (5), (6), (7), (8), (9)) v4(num)
    CROSS JOIN (VALUES (0), (1), (2), (3), (4), (5), (6), (7), (8), (9)) v5(num)
    CROSS JOIN (VALUES (0), (1), (2), (3), (4), (5), (6), (7), (8), (9)) v6(num)
    CROSS JOIN (VALUES (0), (1), (2), (3), (4), (5), (6), (7), (8), (9)) v7(num)


This query shows the status of the alert, as well as when it was last fired:

SELECT AlertName = sa.name
    , Enabled = sa.enabled
    , LastOccurrence = CASE WHEN sa.last_occurrence_date &gt; 0 
        THEN dbo.agent_datetime(sa.last_occurrence_date, sa.last_occurrence_time) 
        ELSE NULL 
        END
    , OccurrenceCount = sa.occurrence_count
    , PerformanceCondition = sa.performance_condition
FROM dbo.sysalerts sa
WHERE sa.name = 'CPUUsage';