System and method for using dynamic thresholds with route isolation for heterogeneous traffic in shared memory packet buffers
A system and method for managing shared memory packet buffers is disclosed. In some embodiments, the system is configured to receive and classify a packet as one of: network-network, network-host, host-network, or host-host; select a minimum guarantee space for the packet according to the classification thereof; if the selected minimum guarantee space is available, store the packet therein; otherwise, if a dedicated shared space is available, store the packet therein; otherwise, if a global shared space is available, store the packet therein; and otherwise, drop the packet.
1 . A method for managing a shared memory for packet traffic, the method comprising:
receiving and classifying a packet as one of: network-network, network-host, host-network, or host-host;
selecting a minimum guarantee space for the packet according to the classification thereof;
in response to the selected minimum guarantee space being available, storing the packet therein;
in response to the selected minimum guarantee space being unavailable and a dedicated shared space being available, storing the packet in the dedicated shared space;
in response to the selected minimum guarantee space and the dedicated shared space being unavailable and a global shared space being available, storing the packet in the global shared space; and
in response to the selected minimum guarantee space, the dedicated shared space, and the global shared space being unavailable, dropping the packet.
2 . A method for managing shared memory packet buffers, the method comprising:
receiving ingress traffic of a traffic type at a server fabric adapter (SFA) communicatively coupled to an ingress entity;
determining, by the SFA, whether a minimum guarantee space of a shared buffer has been allocated for the ingress traffic; and
in response to determining the minimum guarantee space has been allocated for the ingress traffic, forwarding packets of the ingress traffic to the shared buffer in a particular sequence of (1) the minimum guarantee space, (2) a dedicated shared space, and (3) a global shared space, wherein the dedicated shared space is part of the shared buffer allocated to the traffic type after the minimum guarantee space and a headroom have been allocated, and the global shared space is a portion of the shared buffer after the dedicated shared space has been allocated.
3 . The method of claim 2 , wherein:
the ingress entity is one of a host or network entity,
the ingress traffic is one of lossy or lossless traffic, and
the traffic type includes one of network ingress to network egress, network ingress to host egress, host ingress to network egress, and host ingress to host egress.
4 . The method of claim 2 , wherein:
the minimum guarantee space is configured to be available to network ingress traffic or host ingress traffic,
the dedicated shared space is configured to be available only to a particular traffic type, and
the global shared space is configured to be available to all traffic types.
5 . The method of claim 2 , wherein the ingress traffic is lossy traffic, the method further comprising:
in response to determining the minimum guarantee space has not been allocated for the ingress traffic, forwarding the packets of the ingress traffic to the shared buffer in a sequence of (1) the dedicated shared space of the shared buffer allocated to the traffic type and (2) the global shared space of the shared buffer.
6 . The method of claim 2 , wherein forwarding the packets of the ingress traffic to the shared buffer in the particular sequence comprises:
computing a threshold for the ingress entity based on the global shared space and dedicated shared space available to the ingress entity;
determining occupancy of the shared buffer at the ingress entity;
comparing the determined occupancy with the computed threshold; and
taking action to reduce the occupancy of the shared buffer when the determined occupancy exceeds the computed threshold.
7 . The method of claim 6 , wherein the action includes one of discarding packets of the ingress traffic or triggering priority flow control.
8 . The method of claim 7 , further comprising implementing hysteresis by continuing the action until the occupancy reaches a level lower than the threshold.
9 . The method of claim 2 , wherein forwarding the packets of the ingress traffic to the shared buffer in the particular sequence comprises:
determining whether the minimum guarantee space allocated for the ingress traffic is full, wherein the ingress traffic is a host ingress or network ingress;
in response to determining the minimum guarantee space is not full, incrementing a counter associated with the minimum guarantee space and moving at least a portion of the ingress traffic to the minimum guarantee space; and
in response to determining the minimum guarantee space is full, determining whether the dedicated shared space for the ingress traffic is full, wherein the dedicated shared space is allocated based on the traffic type of the ingress traffic;
in response to determining the dedicated shared space is not full, incrementing a counter associated with the dedicated shared space and moving at least a portion of the ingress traffic to the dedicated shared space; and
in response to determining the dedicated shared space is full, incrementing a counter associated with the global shared space and moving at least a portion of the ingress traffic to the global shared space.
10 . The method of claim 2 , wherein the minimum guarantee space, the dedicated shared space, and the global shared space are carved out of the shared buffer through configuration.
11 . The method of claim 2 , further comprising:
receiving egress traffic of the traffic type at a second server fabric adapter (SFA) communicatively coupled to an egress entity, the egress traffic including the packets of the ingress traffic stored in the shared buffer;
determining, by the second SFA, whether the egress traffic occupies the global shared space of the shared buffer;
in response to determining the egress traffic occupies the global shared space, retrieving the egress traffic from the shared buffer in a particular sequence of (1) the global shared space, (2) the dedicated shared space of the shared buffer allocated to the traffic type, and (3) a minimum guarantee space allocated to the egress traffic; and
sending the retrieved traffic to the egress entity.
12 . A system for managing shared memory packet buffers, the system comprising:
a server fabric adapter (SFA) communicatively coupled to an ingress entity, the SFA configured to:
receive ingress traffic of a traffic type;
determine whether a minimum guarantee space of a shared buffer has been allocated for the ingress traffic; and
in response to determining the minimum guarantee space has been allocated for the ingress traffic, forward packets of the ingress traffic to the shared buffer in a particular sequence of (1) the minimum guarantee space, (2) a dedicated shared space, and (3) a global shared space, wherein the dedicated shared space is part of the shared buffer allocated to the traffic type after the minimum guarantee space and a headroom have been allocated, and the global shared space is a portion of the shared buffer after the dedicated shared space has been allocated.
13 . The system of claim 12 , wherein:
the ingress entity is one of a host or network entity,
the ingress traffic is one of lossy or lossless traffic, and
the traffic type includes one of network ingress to network egress, network ingress to host egress, host ingress to network egress, and host ingress to host egress.
14 . The system of claim 12 , wherein:
the minimum guarantee space is configured to be available to network ingress traffic or host ingress traffic,
the dedicated shared space is configured to be available only to a particular traffic type, and
the global shared space is configured to be available to all traffic types.
15 . The system of claim 12 , wherein the ingress traffic is lossy traffic, and the SFA is further configured to:
in response to determining the minimum guarantee space has not been allocated for the ingress traffic, forward the packets of the ingress traffic to the shared buffer in a sequence of (1) the dedicated shared space of the shared buffer allocated to the traffic type and (2) the global shared space of the shared buffer.
16 . The system of claim 12 , wherein to forward the packets of the ingress traffic to the shared buffer in the particular sequence, the SFA is further configured to:
compute a threshold for the ingress entity based on the global shared space and dedicated shared space available to the ingress entity;
determine occupancy of the shared buffer at the ingress entity;
compare the determined occupancy with the computed threshold; and
take action to reduce the occupancy of the shared buffer when the determined occupancy exceeds the computed threshold.
17 . The system of claim 16 , wherein the action includes one of discarding packets of the ingress traffic or triggering priority flow control.
18 . The system of claim 17 , wherein the SFA is further configured to implement hysteresis by continuing the action until the occupancy reaches a level lower than the threshold.
19 . The system of claim 12 , wherein to forward the packets of the ingress traffic to the shared buffer in the particular sequence, the SFA is further configured to:
determine whether the minimum guarantee space allocated for the ingress traffic is full, wherein the ingress traffic is a host ingress or network ingress;
in response to determining the minimum guarantee space is not full, increment a counter associated with the minimum guarantee space and move at least a portion of the ingress traffic to the minimum guarantee space; and
in response to determining the minimum guarantee space is full, determine whether the dedicated shared space for the ingress traffic is full, wherein the dedicated shared space is allocated based on the traffic type of the ingress traffic;
in response to determining the dedicated shared space is not full, increment a counter associated with the dedicated shared space and move at least a portion of the ingress traffic to the dedicated shared space; and
in response to determining the dedicated shared space is full, increment a counter associated with the global shared space and move at least a portion of the ingress traffic to the global shared space.
20 . The system of claim 12 , further comprising:
a second SFA communicatively coupled to an egress entity, the second SFA configured to:
receive egress traffic of the traffic type, the egress traffic including the packets of the ingress traffic stored in the shared buffer;
determine whether the egress traffic occupies the global shared space of the shared buffer;
in response to determining the egress traffic occupies the global shared space, retrieve the egress traffic from the shared buffer in a particular sequence of (1) the global shared space, (2) the dedicated shared space of the shared buffer allocated to the traffic type, and (3) a minimum guarantee space allocated to the egress traffic; and
send the retrieved traffic to the egress entity.