sharepoit performance counter instance name with [ACL]

Select a Sharepoint performance counter object, there are two instances for each of my web site. For example, for the ssp site, the two instance are named as

1. portnumber_ssp_admin
2. portnumber_ssp_admin[ACL]

What is the difference between the two i开发者_C百科nstances? What is the meaning of [ACL]?

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ACL are access control lists, so it probably means the second one takes security into account.