sql-server-2008 - SQL Server 2008 R2 中的负利用率数

Question

在我们的暂存环境中运行性能测试时，我偶尔会运行以下查询：

declare @ts_now bigint 
select @ts_now = ms_ticks from sys.dm_os_sys_info 

select  dateadd (ms, (y.[timestamp] -@ts_now),
GETDATE()) as EventTime,
SQLProcessUtilization, 
SystemIdle, 
100 - SystemIdle - SQLProcessUtilization as OtherProcessUtilization 
from 
    ( select record.value('(./Record/@id)[1]', 'int') as record_id, 
    record.value('(./Record/SchedulerMonitorEvent/SystemHealth/SystemIdle)[1]', 'int') as SystemIdle, 
    record.value('(./Record/SchedulerMonitorEvent/SystemHealth/ProcessUtilization)[1]', 'int') as SQLProcessUtilization, 
    timestamp 
    from 
        ( select timestamp, 
        convert(xml, record) as record 
        from sys.dm_os_ring_buffers 
        where ring_buffer_type = N'RING_BUFFER_SCHEDULER_MONITOR'
        and record like '%<SystemHealth>%') as x 
    ) as y

这返回

谁能解释我如何得到一个负数的利用率？我在尝试从 SQL Server CPU 利用率大于系统 CPU 利用率的 PSS 诊断中找出 CPU 利用率问题时发现了这一点。

我还没有弄清楚这两个问题，但我必须假设它们是相关的。