1. A method for distributing application traffic received by a service gateway from a host to a server of a plurality of servers, based on dynamic service response time of the server, the method comprising: receiving a first service request for a service session from the host by the service gateway; determining by the service gateway a service request time for the service session; relaying the first service request from the service gateway to a first server of the plurality of servers, the relaying occurring over the service session between the service gateway and the first server; receiving by the service gateway a service response from the first server; determining by the service gateway a service response time; calculating by the service gateway a dynamic service processing time for the first service request from the service request time and the service response time; comparing the dynamic service processing time with an expected service processing time for the first server to determine whether the dynamic service processing time exceeds the expected service processing time by at least a threshold amount, wherein the expected service processing time is determined by the service gateway according to a service attribute of the first service request or according to a service attribute of the first server, wherein the expected service processing time is based on the service attribute of the first service request or a service attribute of the first server and stored in a datastore, wherein the determining the expected service processing time comprises: comparing by the service gateway the first service request or the first server with the service attribute in the datastore; and if the first service request or the first server matches the service attribute in the datastore, retrieving the expected service processing time associated with the matching service attribute, wherein the expected service processing time is variable based on the matching service attribute; updating a server busy indicator for the first server in response to the comparing, wherein a server busy indicator for each of the plurality of servers is maintained at the service gateway; receiving a second service request from the host by the service gateway; checking the server busy indicator for the first server by the service gateway; in response to determining that the server busy indicator indicates that the first server is busy, placing the second service request in a service request buffer of the service gateway and maintaining a connection to the host; and in response to determining that the server busy indicator indicates that the first server is not busy, relaying the second service request from the service gateway to the first server over the service session between the service gateway and the first server.