Quality of service aware rate throttling of delay tolerant traffic for energy efficient routing

Abstract

The invention is directed to energy-efficient network processing of delay tolerant data packet traffic. Embodiments of the invention determine if an aggregate of time critical traffic flow rates and minimum rates for meeting QoS requirements of delay tolerant traffic flows exceeds a combined optimal rate of packet processing engines of a network processor. In the affirmative case, embodiments set the processing rate of individual packet processing engines to a minimum rate, such that the cumulative rate of the packet processing engines meets the aggregate rate, and schedule the delay tolerant flows to meet their respective minimum rates. Advantageously, by throttling the processing rate of only delay tolerant traffic, energy consumption of network processors can be reduced while at the same time QoS requirements of the delay tolerant traffic and time critical traffic can be met.

1 . A method performed by a network processor for controlling a processing rate, the method comprising:
 identifying a delay tolerant flow that is being processed by the network processor at a first current flow rate;   determining a quality of service (QoS) requirement associated with the delay tolerant flow;   determining a reduced flow rate for the delay tolerant flow, wherein
 the reduced flow rate is less than the first current flow rate, and 
 the reduced flow rate is sufficient to fulfill the QoS requirement; and 
   reducing the processing rate of the network processor based on the reduced flow rate.   
     
     
         2 . The method of  claim 1 , further comprising:
 identifying a time critical flow that is being processed by the network processor at a second current flow rate; and   obtaining a summed rate based on a sum of the reduced flow rate and the second current flow rate,   wherein reducing the processing rate of the network processor based on the reduced flow rate comprises reducing the processing rate based on the summed rate.   
     
     
         3 . The method of  claim 1 , wherein reducing the processing rate of the network processor based on the reduced flow rate comprises:
 determining an optimal rate of a plurality of packet processing engine (PPE) of the network processor, wherein the optimal rate is selected to provide energy efficient processing relative to other possible rates;   determining that reduction of processing rates of the PPE based on the reduced flow rate would reduce the processing rate of the PPE below the optimal rate; and   in response to determining that reduction of processing rates of the PPE based on the reduced flow rate would reduce the processing rate of a PPE below the optimal rate, deactivating at least one PPE of the plurality of PPEs.   
     
     
         4 . The method of  claim 1 , wherein:
 identifying the delay tolerant flow comprises identifying a plurality of delay tolerant flows being processed by the network processor at a first aggregate flow rate;   determining a reduced flow rate for the delay tolerant flow comprises determining an aggregate reduced flow rate for the plurality of delay tolerant flows based on QoS requirements associated with the plurality of delay tolerant flows; and   reducing the processing rate of the network processor based on the reduced flow rate comprises reducing the processing rate of the network processor based on the aggregate reduced flow rate.   
     
     
         5 . The method of  claim 4 , further comprising:
 identifying a plurality of time critical flows being processed by the network processor at a second aggregate flow rate;   obtaining a summed rate based on a sum of the aggregate reduced flow rate and the second aggregate flow rate,   wherein reducing the processing rate of the network processor based on the aggregate reduced flow rate comprises setting the processing rate of the network processor to substantially equal the summed rate.   
     
     
         6 . The method of  claim 5 , wherein the network processor comprises a plurality of packet processing engines (PPEs) and setting the processing rate of the network processor to substantially equal the summed rate comprises:
 determining an energy efficient rate for a PPE of the plurality of PPEs;   determining that the summed rate is less than the energy efficient rate multiplied by the number of PPEs in the plurality of PPEs;   based on determining that the summed rate is less than the energy efficient rate multiplied by the number of PPEs in the plurality of PPEs, deactivating at least one PPE of the plurality of PPEs.   
     
     
         7 . The method of  claim 5 , wherein the network processor comprises a plurality of packet processing engines (PPEs) and setting the processing rate of the network processor to substantially equal the summed rate comprises reducing a rate of at least one PPE of the plurality of PPEs based on the summed rate. 
     
     
         8 . A rate controllable network processor comprising:
 a rate estimator configured to:
 identify a delay tolerant flow that is being processed by the network processor at a first current flow rate, 
 determine a quality of service (QoS) requirement associated with the delay tolerant flow, and 
 determine a reduced flow rate for the delay tolerant flow, wherein
 the reduced flow rate is less than the first current flow rate, and 
 the reduced flow rate is sufficient to fulfill the QoS requirement; and 
 
   a rate controller configured to reduce a processing rate of the network processor based on the reduced flow rate.   
     
     
         9 . The rate controllable network processor of  claim 8 , wherein:
 the rate estimator is further configured to:
 identify a time critical flow that is being processed by the network processor at a second current flow rate, and 
 obtain a summed rate based on a sum of the reduced flow rate and the second current flow rate; and 
   in reducing the processing rate of the network processor based on the reduced flow rate, the rate controller is configured to reduce the processing rate based on the summed rate.   
     
     
         10 . The rate controllable network processor of  claim 8 , further comprising a plurality of packet processing engines (PPEs) wherein, in reducing the processing rate of the network processor based on the reduced flow rate, the rate controller is configured to:
 determine an optimal rate of a PPE of the plurality of PPEs of the network processor, wherein the optimal rate is selected to provide energy efficient processing relative to other possible rates,   determine that reduction of processing rates of the plurality of PPEs based on the reduced flow rate would reduce the processing rate of the PPE below the optimal rate, and   in response to determining that reduction of processing rates of the plurality of PPEs based on the reduced flow rate would reduce the processing rate of a PPE below the optimal rate, deactivate at least one PPE of the plurality of PPEs.   
     
     
         11 . The rate controllable network processor of  claim 8 , wherein:
 in identifying the delay tolerant flow, the rate estimator is configured to identify a plurality of delay tolerant flows being processed by the network processor at a first aggregate flow rate;   in determining a reduced flow rate for the delay tolerant flow, the rate estimator is configured to determine an aggregate reduced flow rate for the plurality of delay tolerant flows based on QoS requirements associated with the plurality of delay tolerant flows; and   in reducing the processing rate of the network processor based on the reduced flow rate, the rate controller is configured to reduce the processing rate of the network processor based on the aggregate reduced flow rate.   
     
     
         12 . The rate controllable network processor of  claim 11 , wherein:
 the rate estimator is further configured to:
 identify a plurality of time critical flows being processed by the network processor at a second aggregate flow rate, 
 obtain a summed rate based on a sum of the aggregate reduced flow rate and the second aggregate flow rate; and 
   in reducing the processing rate of the network processor based on the aggregate reduced flow rate, the rate controller is configured to set the processing rate of the network processor to substantially equal the summed rate.   
     
     
         13 . The rate controllable network processor of  claim 12 , further comprising a plurality of packet processing engines (PPEs), wherein, in setting the processing rate of the network processor to substantially equal the summed rate, the rate controller is configured to:
 determine an energy efficient rate for a PPE of the plurality of PPEs;   determine that the summed rate is less than the energy efficient rate multiplied by the number of PPEs in the plurality of PPEs;   based on determining that the summed rate is less than the energy efficient rate multiplied by the number of PPEs in the plurality of PPEs, deactivate at least one PPE of the plurality of PPEs.   
     
     
         14 . The rate controllable network processor of  claim 12 , further comprising a plurality of packet processing engines (PPEs), wherein, in setting the processing rate of the network processor to substantially equal the summed rate, the rate controller is configured to reduce a rate of at least one PPE of the plurality of PPEs based on the summed rate. 
     
     
         15 . A non-transitory machine readable storage medium encoded with instructions for execution by a network processor for controlling a processing rate, the medium comprising:
 instructions for identifying a delay tolerant flow that is being processed by the network processor at a first current flow rate;   instructions for determining a quality of service (QoS) requirement associated with the delay tolerant flow;   instructions for determining a reduced flow rate for the delay tolerant flow, wherein
 the reduced flow rate is less than the first current flow rate, and 
 the reduced flow rate is sufficient to fulfill the QoS requirement; and 
   instructions for reducing the processing rate of the network processor based on the reduced flow rate.   
     
     
         16 . The non-transitory machine readable storage medium of  claim 15 , further comprising:
 instructions for identifying a time critical flow that is being processed by the network processor at a second current flow rate; and   instructions for obtaining a summed rate based on a sum of the reduced flow rate and the second current flow rate,   wherein the instructions for reducing the processing rate of the network processor based on the reduced flow rate comprise instructions for reducing the processing rate based on the summed rate.   
     
     
         17 . The non-transitory machine readable storage medium of  claim 15 , wherein the instructions for reducing the processing rate of the network processor based on the reduced flow rate comprise:
 instructions for determining an optimal rate of a packet processing engine (PPE) of a plurality of PPEs of the network processor, wherein the optimal rate is selected to provide energy efficient processing relative to other possible rates;   instructions for determining that reduction of processing rates of the plurality of PPEs based on the reduced flow rate would reduce the processing rate of the PPE below the optimal rate; and   instructions for, in response to determining that reduction of processing rates of the plurality of PPEs based on the reduced flow rate would reduce the processing rate of a PPE below the optimal rate, deactivating at least one PPE of the plurality of PPEs.   
     
     
         18 . The non-transitory machine readable storage medium of  claim 15 , wherein:
 the instructions for identifying the delay tolerant flow comprise instructions for identifying a plurality of delay tolerant flows being processed by the network processor at a first aggregate flow rate;   the instructions for determining a reduced flow rate for the delay tolerant flow comprise instructions for determining an aggregate reduced flow rate for the plurality of delay tolerant flows based on QoS requirements associated with the plurality of delay tolerant flows; and   the instructions for reducing the processing rate of the network processor based on the reduced flow rate comprise instructions for reducing the processing rate of the network processor based on the aggregate reduced flow rate.   
     
     
         19 . The non-transitory machine readable storage medium of  claim 18 , further comprising;
 instructions for identifying a plurality of time critical flows being processed by the network processor at a second aggregate flow rate;   instructions for obtaining a summed rate based on a sum of the aggregate reduced flow rate and the second aggregate flow rate,   wherein the instructions for reducing the processing rate of the network processor based on the aggregate reduced flow rate comprise instructions for setting the processing rate of the network processor to substantially equal the summed rate.   
     
     
         20 . The non-transitory machine readable storage medium of  claim 19 , wherein the instructions for setting the processing rate of the network processor to substantially equal the summed rate comprise:
 instructions for determining an energy efficient rate for a packet processing engine (PPE) of a plurality of PPEs;   instructions for determining that the summed rate is less than the energy efficient rate multiplied by the number of PPEs in the plurality of PPEs;   instructions for, based on determining that the summed rate is less than the energy efficient rate multiplied by the number of PPEs in the plurality of PPEs, deactivating at least one PPE of the plurality of PPEs.