A method of assessing latency of forwarding data packets in a host configured to enable I/O virtualization for a virtual platform, VP, or a VP chain running thereon, the method comprising, within the host: upon specifying a transmitting monitoring point associated with a first virtual function, VF, corresponding to an ingress virtual port of the VP or the VP chain and a receiving monitoring point associated with a second VF corresponding to an egress virtual port of the VP or the VP chain, generating packet signatures, SGs, for at least part of data packets eligible for monitoring, thus giving rise to monitored departing packets, each uniquely characterized by respective SG D and to monitored arriving packets each uniquely characterized by respective SG A; maintaining a first data structure comprising a plurality of records related to monitored departing packets associated with the first VF, each record among the plurality of records further informative of, at least, SG D and registered departure time T D of a given departing packet, wherein departure time T D is indicative of departure time of the given packet departing from the transmitting monitoring point to the VP or the VP chain; responsive to registering arriving time T A of a given monitored arriving packet SG A associated with the second VF, searching the first data structure for a record matching a matching condition, wherein the matching condition at least comprises requirement that SG D = SG A, and wherein arriving time T A is indicative of arriving time of the given packet arriving from the VP or the VP chain at the receiving monitoring point; modifying the matching record, when found, to become informative of latency ΔT=T A -T D and adding the modified matching record to a second data structure storing one or more modified records, each informative of latency measured for forwarding a respective packet from the transmitting monitoring point to the receiving monitoring point; and enabling using data in the second data structure for assessing latency of forwarding packets from the ingress virtual port to the egress virtual port of the virtual platform or the VP chain. upon specifying a transmitting monitoring point associated with a first virtual function, VF, corresponding to an ingress virtual port of the VP or the VP chain and a receiving monitoring point associated with a second VF corresponding to an egress virtual port of the VP or the VP chain, generating packet signatures, SGs, for at least part of data packets eligible for monitoring, thus giving rise to monitored departing packets, each uniquely characterized by respective SG D and to monitored arriving packets each uniquely characterized by respective SG A; maintaining a first data structure comprising a plurality of records related to monitored departing packets associated with the first VF, each record among the plurality of records further informative of, at least, SG D and registered departure time T D of a given departing packet, wherein departure time T D is indicative of departure time of the given packet departing from the transmitting monitoring point to the VP or the VP chain; responsive to registering arriving time T A of a given monitored arriving packet SG A associated with the second VF, searching the first data structure for a record matching a matching condition, wherein the matching condition at least comprises requirement that SG D = SG A, and wherein arriving time T A is indicative of arriving time of the given packet arriving from the VP or the VP chain at the receiving monitoring point; modifying the matching record, when found, to become informative of latency ΔT=T A -T D and adding the modified matching record to a second data structure storing one or more modified records, each informative of latency measured for forwarding a respective packet from the transmitting monitoring point to the receiving monitoring point; and enabling using data in the second data structure for assessing latency of forwarding packets from the ingress virtual port to the egress virtual port of the virtual platform or the VP chain.