Server device and communication connection scheme using network interface processors

Abstract

A server device and a communication connection scheme capable of expanding the memory bandwidth and thereby expanding the power to transmit Web data to the network are disclosed. Network cards are detachably attached to a host machine (main machine). Each network card contains a processor, a memory, and a network interface unit, where data are transmitted to the network from a memory on the network card and the memory bandwidth expansion is realized by the presence of a plurality of network cards. In addition, using a memory of the network card as a cache, the load on the host machine is reduced by transmitting data from this memory to the network when the data exists on the memory and a certain condition is satisfied.

What is claimed is:  
     
         1 . A server device, comprising: 
 a main machine having a main processor for controlling the main machine, and a main memory for storing server data; and    a plurality of network interface processor units connected to the main machine, each network interface processor unit having a local processor for controlling each network interface processor unit independently from the main machine, a local memory for storing a part of the server data, and a local network controller for communicating with an external device through a network, wherein the local processor controls the local memory and the local network controller such that a data requested by the external device is transmitted to the external device from the local memory through the local network controller when the requested data is stored in the local memory and a prescribed condition is satisfied, and requests transfer of the requested data to the main machine when the requested data is not stored in the local memory or the prescribed condition is not satisfied such that the requested data read out from the main memory is transmitted to the external device through the local network controller.    
     
     
         2 . The server device of  claim 1 , wherein the main network machine includes: 
 a main network controller for communicating with the external device through the network;    selection means for selecting one network interface processor unit among said plurality of network interface processor units according to a prescribed rule upon accepting an initial request from the external device through the main network controller; and    re-direction means for re-directing the external device to said one network interface processor unit selected by the selection means so that the external device makes a subsequent request to said one network interface processor unit.    
     
     
         3 . The server device of  claim 2 , wherein the selection means first selects a first network interface processor unit according to the prescribed rule as said one network interface processor unit, and when a load on the first network interface processor unit is higher than a prescribed threshold, selects a second network interface processor unit with a load lower than another prescribed threshold among said plurality of network interface processor units as said one network interface processor unit.  
     
     
         4 . The server device of  claim 3 , wherein the main network machine further includes: 
 calculation means for calculating an average response time of each network interface processor unit and storing the calculated average response time in correspondence to each network interface processor unit as an information indicating the load on each network interface processor unit.    
     
     
         5 . The server device of  claim 2 , wherein the selection means uses the prescribed rule based on a static strategy for selecting said one network interface processor unit regardless of a state of said one network interface processor unit.  
     
     
         6 . The server device of  claim 2 , wherein the selection means uses the prescribed rule which determines said one network interface processor unit according to a hash function value based on an address contained in the request.  
     
     
         7 . The server device of  claim 1 , wherein the local processor of each network interface processor unit enters the requested data read out from the main memory into the local memory when an entering condition is satisfied.  
     
     
         8 . The server device of  claim 1 , wherein the local processor of each network interface processor unit judges whether the prescribed condition is satisfied or not independently.  
     
     
         9 . The server device of  claim 1 , wherein the main processor updates the server data in the main memory when a data writing from the network to the main machine occurs, and notifies updating of the server data to each network interface processor unit.  
     
     
         10 . The server device of  claim 1 , wherein each network interface processor unit is provided in a form of a network card to be detachably attached to the main machine.  
     
     
         11 . A network interface processor device to be connected to a main machine of the server device having a main processor for controlling the main machine and a main memory for storing server data, the network interface processor device comprising: 
 a local processor for controlling each network interface processor unit independently from the main machine;    a local memory for storing a part of the server data; and    a local network controller for communicating with an external device through a network;    wherein the local processor controls the local memory and the local network controller such that a data requested by the external device is transmitted to the external device from the local memory through the local network controller when the requested data is stored in the local memory and a prescribed condition is satisfied, and requests transfer of the requested data to the main machine when the requested data is not stored in the local memory or the prescribed condition is not satisfied such that the requested data read out from the main memory is transmitted to the external device through the local network controller.    
     
     
         12 . The network interface processor device of  claim 1 , wherein the local processor enters the requested data read out from the main memory into the local memory when an entering condition is satisfied.  
     
     
         13 . The network interface processor device of  claim 1 , wherein the local processor judges whether the prescribed condition is satisfied or not independently.  
     
     
         14 . The network interface processor device of  claim 1 , wherein the local processor, the local memory, and the local network controller are collectively provided in a form of a network card to be detachably attached to the main machine.  
     
     
         15 . A communication method for a server device formed by a main machine having a main processor for controlling the main machine and a main memory for storing server data, and a plurality of network interface processor units connected to the main machine, each network interface processor unit having a local processor for controlling each network interface processor unit independently from the main machine, a local memory, and a local network controller for communicating through a network, the method comprising the steps of: 
 setting up each network interface processor unit by storing a part of the server data in the local memory;    transmitting a data requested by an external device to the external device from the local memory through the local network controller when the requested data is stored in the local memory and a prescribed condition is satisfied, at one of the network interface processor units; and    requesting transfer of the requested data to the main machine when the requested data is not stored in the local memory or the prescribed condition is not satisfied, and transmitting the requested data read out from the main memory to the external device through the local network controller, at said one of the network interface processor units.    
     
     
         16 . The method of  claim 15 , further comprising the steps of: 
 selecting said one of the network interface processor units among said plurality of network interface processor units according to a prescribed rule at the main machine, upon accepting an initial request from the external device; and    re-directing the external device to said one of the network interface processor units selected by the selecting step so that the external device makes a subsequent request to said one network interface processor unit.    
     
     
         17 . The method of  claim 16 , wherein the selecting step first selects a first network interface processor unit according to the prescribed rule as said one of the network interface processor units, and when a load on the first network interface processor unit is higher than a prescribed threshold, selects a second network interface processor unit with a load lower than another prescribed threshold among said plurality of network interface processor units as said one of the network interface processor units.  
     
     
         18 . The method of  claim 17 , further comprising the steps of: 
 calculating an average response time of each network interface processor unit, in the main processor; and    storing the average response time calculated by the calculating step in correspondence to each network interface processor unit as an information indicating the load on each network interface processor unit, in the main memory.    
     
     
         19 . The method of  claim 16 , wherein the selecting step uses the prescribed rule based on a static strategy for selecting said one of the network interface processor units regardless of a state of each network interface processor unit.  
     
     
         20 . The method of  claim 16 , wherein the selecting step uses the prescribed rule which determines said one of the network interface processor units according to a hash function value based on an address contained in the request.  
     
     
         21 . The method of  claim 15 , further comprising the step of: 
 entering the requested data read out from the main memory into the local memory when an entering condition is satisfied, at said one of the network interface processor units.    
     
     
         22 . The method of  claim 15 , wherein at the transmitting step, the local processor of each network interface processor unit judges whether the prescribed condition is satisfied or not independently.  
     
     
         23 . The method of  claim 15 , further comprising the step of: 
 updating the server data in the main memory when a data writing from the network to the main machine occurs, and notifying updating of the server data to each network interface processor unit from the main processor.    
     
     
         24 . An article of manufacture, comprising: 
 a computer usable medium having computer readable program code means embodied therein for causing a computer to function as a network interface processor device to be connected to a main machine of the server device having a main processor for controlling the main machine and a main memory for storing server data, the network interface processor device having a local processor for controlling each network interface processor unit independently from the main machine, a local memory for storing a part of the server data, and a local network controller for communicating with an external device through a network, the computer readable program code means includes: 
 first computer readable program code means for causing said computer to transmit a data requested by the external device to the external device from the local memory through the local network controller when the requested data is stored in the local memory and a prescribed condition is satisfied; and  
 second computer readable program code means for causing said computer to request transfer of the requested data to the main machine when the requested data is not stored in the local memory or the prescribed condition is not satisfied, and transmit the requested data read out from the main memory to the external device through the local network controller.  
   
     
     
         25 . An article of manufacture, comprising: 
 a computer usable medium having computer readable program code means embodied therein for causing a computer to function as a main machine of the server device having a main processor for controlling the main machine, a main memory for storing server data, and a main network controller for communicating with an external device through a network, the main machine being connected with a plurality of network interface processor units, each network interface processor unit having a local processor for controlling each network interface processor unit independently from the main machine, a local memory for storing a part of the server data, and a local network controller for communicating with the external device through the network, the computer readable program code means includes: 
 first computer readable program code means for causing said computer to select one network interface processor unit among said plurality of network interface processor units according to a prescribed rule upon accepting a request from the external device through the main network controller, such that the selected network interface processor unit transmits a data requested by the external device to the external device from the local memory through the local network controller when the requested data is stored in the local memory and a prescribed condition is satisfied; and  
 second computer readable program code means for causing said computer to transfer the requested data from the main memory to the selected network interface processor unit when the requested data is not stored in the local memory or the prescribed condition is not satisfied.