1. A method for request profiling in service systems with kernel events, comprising the steps of: collecting kernel events traces from a target system, said kernel event traces obtainable from individual service machines by instrumenting core kernel functions; analyzing kernel event traces for constructing end-to-end request profiling traces consisting of kernel events belonging to service processes; and categorizing request traces responsive to said analyzing step, said constructing including grouping requests based on marking kernel events used in said analyzing step; wherein said end-to-end request profiling comprises: generating request units from collected kernel events based on a configurable marking event set; and constructing full-path request traces by composing relevant requests units based on a causality relationship set which is between request units and defined on the marking event set and temporal relationships, wherein said step of constructing full-path requests comprises defining a causality relationship set including event association rules each presented as a 5 tuple record: causing event type, caused event type, time rule, owner rule and event data rule.