Abstract:
In general, in one aspect, the disclosure describes a method that includes automatically applying different sets of parameter values to a network interface component, storing performance data for the network interface component for the different sets of parameter values, and selecting a one of the different sets of parameters values based on the performance data.

Description:
BACKGROUND  
         [0001]    Computers and other devices connect to networks via network interface components. For example, many computer systems feature a network interface card (NIC) that acts as an intermediary between a communication medium, such as a network cable, and other system components. Generally, a NIC includes a physical layer (PHY) component that converts between the physical signals (e.g., wire voltages) of the communication medium and the “1”-s and “0”-s used by digital devices. The NIC may also perform other operations. For example, the NIC may include logic to identify logical groupings of bits known as protocol data units (PDUs). For instance, a NIC may identify a logical group of bits known as a “frame”. A frame usually includes bits that identify the start and end of the frame and data used to verify correct transmission of the frame. A frame may encapsulate other PDUs such as datagrams, packets, or cells. Potentially, the NIC may extract (“de-encapsulate”) these other PDUs from within the frame.  
           [0002]    After receiving data, a NIC may notify other system components of the data&#39;s arrival. For example, the NIC may transfer received data to memory accessible to a host processor and alert the host processor to the data by generating an interrupt signal.  
           [0003]    Many network interface components may be configured by the settings of different parameters. For example, some parameters may control how often a NIC issues an interrupt signal. A high value can cause the NIC to accumulate several PDUs before sending an interrupt while a low value may cause the NIC to send an interrupt after each protocol data unit arrives. Thus, the setting represents a tradeoff between conserving processor resources by issuing fewer interrupts and increasing the speed of PDU processing by issuing interrupts more frequently.  
           [0004]    A wide variety of other parameters can affect NIC operation. For example, parameters can control memory resources used by the NIC. For instance, parameters may control the amount of memory allocated to the NIC to hold received PDUs. While a high parameter value may prevent the NIC from running low on memory resources, a high value increases the memory resources consumed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 is a diagram of a system including a network interface component.  
         [0006]    [0006]FIG. 2 is a flowchart of a process to determine parameter settings for different network traffic.  
         [0007]    [0007]FIG. 3 is a flowchart of a process to apply parameters to a network interface component. 
     
    
     DETAILED DESCRIPTION  
       [0008]    Parameter settings can greatly affect the performance of a network interface component. For example, parameter settings may affect throughput of the component and/or the load placed on processor resources (e.g. processor utilization and memory).  
         [0009]    The performance provided by a given set of settings, however, may vary depending on a variety of factors. For example, network interface component parameters will have a different impact on performance depending on the network traffic handled by the network interface. For example, a File Transfer Protocol (FTP) server transmitting a large file will generally be transmitting a large number of larger PDUs. Thus, the network interface component of an FTP server would likely benefit from a large allocation of transmit resources. Since the timing of file transfer is of lesser importance, interrupts can be heavily moderated. An audio streaming server, however, will transmit many small, time-sensitive PDUs. Thus, an audio streaming server may benefit from increasing processor interrupts. In this example, parameter settings suited for one kind of traffic may result in poor performance for the other and vice versa.  
         [0010]    In addition to different network traffic, parameter settings may have a different performance impact in different system environments. For example, systems may vary in terms of their memory architectures, processor speeds, buses, operating systems, available memory, and so forth.  
         [0011]    The oftentimes unpredictable interaction between different parameters further complicate the task of determining suitable parameter values. Thus, a painstaking theoretical development of a set of parameter values for a given environment may sometimes provide performance that could be improved upon.  
         [0012]    This disclosure describes techniques that automatically tune network interface component parameter settings. To determine settings, logic automatically tests different sets of parameter values and measures the resulting performance. The testing can explore a wide variety of parameter setting combinations. A particular set of parameter values may be selected from those tested by comparing the performance to specified criteria. Automatic exploration of “parameter-space” can often identify parameter settings that offer better performance than settings derived from theoretical predictions.  
         [0013]    To illustrate, FIG. 1 depicts a system  100  that includes a network interface card  102  (a.k.a. a network adapter) that provides access to a network. The network interface card  102  may feature a physical layer (PHY) component (e.g., a wired, optic, or wireless PHY) that connects the card  102  to a network connection. The network interface card  102  also features an interface to a bus (e.g., a Peripheral Component Interconnect (PCI), PCI Express, Universal Serial Bus (USB) interface, Infiniband, or HyperTransport™ bus) that enables the network interface card  102  to communicate with system  100  components such as host processor(s)  104  or other network components such as a Transmission Control Protocol/Internet Protocol (TCP/IP) Offload Engine (not shown). The network interface card  102  may handle data transfer (e.g., using Direct Memory Access (DMA)) and interrupt signaling with other system  100  components (e.g., host processor(s)  104 ).  
         [0014]    Again, the network interface card  102  can perform a variety of data communication operations such as physical and link layer (e.g., framing) operations. For example, the network interface card  102  may provide operations for processing Synchronous Optical NETwork (SONET) and/or Ethernet frames (e.g., performing error detection, identifying frame boundaries, and so forth).  
         [0015]    As shown, FIG. 1 also depicts data  106  that identifies different sets of network interface parameter values  110  associated with different environments. For example, as shown, the data  106  may identify sets of parameter values  110  for different types of network traffic  108 . After selection or detection of network traffic, the parameters associated with the traffic may be applied to the network interface component  102 .  
         [0016]    In the example shown, the different sets of parameters are associated with a traffic type identifier  108 . For instance, identifiers  108  may represent traffic of different network communication protocols that operate at different layers in the protocol stack (e.g., the link layer, network layer, application layer, Asynchronous Transfer Mod (ATM) adaptation layer). For example, application layer traffic types may include Hypertext Transfer Protocol (HTTP), Simple Mail Transfer Protocol (SMTP), or File Transfer Protocol (FTP). Instead of identifying a particular protocol or application, the traffic type may identify a generic class of application such as “streaming audio” or “network backup”.  
         [0017]    In addition to, or instead of, an identifier, the parameters may be associated with “finer grained” characteristics of the network traffic such as the number and duration of connections (e.g., TCP/IP connections or ATM circuits), PDU size average and distribution, and so forth. Alternately, or in addition, a given tuple (“row”) of parameters may be associated with different system characteristics (e.g., operating system, bus, processor speed, memory, and so forth). Thus, a lookup for the parameter settings to apply may be keyed by one or more traffic and/or system characteristics.  
         [0018]    Different network interface components may be configured by different parameters. These parameters may include control over interrupts (e.g., interrupt moderation settings and packets processed per interrupt), memory resources (e.g., transmit buffers and management structures, receive buffers and management structures), and other component operations (e.g., bus interface utilization modes).  
         [0019]    The specific parameters may vary based on the network interface component being tuned. As an example, parameters of an Intel Pro Network Adapter may: control coalescing of packet portions into a smaller number of buffers (e.g., the number of coalesce buffers, the coalescing algorithm used, and limits on the size of buffers to be coalesced); identify resources for receiving packets (e.g., the number of receive buffers available to store packets, the number of receive descriptors identifying the receive buffers, the number of receive descriptors returned for reuse at a time, the minimum number of available receive descriptors to handle an arriving packet); identify resources for transmitting packets (e.g., the number of transmit descriptors); control delays between packet reception/transmission and interrupt signaling; control operation of a Deferred Procedure Call (DPC) loop (e.g., the number of iterations to perform a DPC loop at a time and the number of packets provided per DPC loop); parameters that control communication with a host (e.g., how many packets indicated to a protocol stack at a time, whether Memory Write and Invalidate (MWI) transactions are enabled, DMA priority between receive and transmit operations); control TCP operation (e.g., segmentation, maximum window size, number of Transport Control Blocks (TCBs) available); and so forth. Again, the parameters identified above are merely illustrative. A wide variety of other parameters may be used in the tuning process.  
         [0020]    Though shown as residing locally, the parameter data  106  may reside at a remote site. Further, though shown as accessible to both the network interface card  102  and other host components  104 , either the network interface component  102  or host processor(s)  104  may include tuning logic and/or have access to the parameter data  106 . Potentially, the data  106  may be modified as the on-going performance of the component  102  is monitored.  
         [0021]    [0021]FIG. 2 depicts a sample process that can automatically generate and select parameter settings tailored to a particular environment (e.g., host system, network traffic, and/or network interface component characteristics). As shown, the process selects  134  a set of parameter values based on performance goals  120 . The performance goals  120  can include a variety of metrics such as throughput (e.g., measured in bytes transmitted and received), memory usage, processor utilization, interrupts per second, and DPC loop count, among others.  
         [0022]    As shown in FIG. 2, the process automatically applies  124  different sets of parameter values to a network interface component. For example, a first set of parameter values may set NumberReceiveBuffers to N and NumberTransmitBuffers to M, while a second set of parameters values sets NumberReceiveBuffers to N+1 and NumberTransmitBuffers to M- 1 .  
         [0023]    Potentially, application of the values may require system rebooting and/or network interface component disabling and enabling. For each set of parameters, the process can cause generation  126  of network traffic having specified characteristics  122  (e.g., by invoking a batch file). Again, characteristics of the traffic can include the number and duration of connections, PDU size average and distribution, and so forth. As the interface handles the generated traffic, the process compiles  128  performance statistics. After monitoring the performance for the generated traffic, the process can determine  132  a new set of parameters to test.  
         [0024]    To determine the parameter values to test, the process may use a “brute force” exhaustive evaluation of all different setting combinations. To speed testing, the process may instead automatically select or permit input of parameters to vary and acceptable discrete values or value ranges, thereby reducing the number of permutations to be explored. Alternately, the process may apply programmed heuristics (e.g., if CPU usage is too high, reduce interrupt signaling) or statistical design of experiments methodology.  
         [0025]    Eventually, the process completes  130  testing of different sets of parameter values. For example, the process may finish testing parameter value permutations. Alternately, the process may gauge its progress toward an acceptable set of parameter settings, for example, by comparing a distance measurement between achieved and desired performance across tests. After testing completes  130 , the process can select  134  a set of parameter values from those empirically tested. For example, the process can select the parameter settings closest to or furthest exceeding the performance goals  120 .  
         [0026]    The process shown in FIG. 2 has a wide variety of applications. For example, the process may be used to generate a table of settings (e.g., data  106  in FIG. 1) and/or determine factory settings that a component is shipped with. Alternately, the process may be an ongoing one. That is, a process may monitor component performance and search for better settings, for example, when performance degrades.  
         [0027]    [0027]FIG. 3 depicts a process that configures a network interface component to parameter settings selected for particular network traffic/system characteristics. The process may statically provision the network interface component based on the anticipated environment. Alternately, the parameter values used may be dynamically selected as performance and traffic characteristics are monitored during “live” system  100  operation.  
         [0028]    As shown, the process determines  150  network traffic handled by the network interface. For example, an operator may specify a particular type of traffic (e.g., by interacting with a user interface or data file). Alternately, the traffic may be determined automatically, for example, by monitoring characteristics of traffic being handled (e.g., protocol, application, incoming message size, outbound message size, incoming message volume, outbound message volume, and so forth). Based on the determined network traffic and/or system characteristics, the process can lookup  152  the parameters selected for such a setting. These parameters may then be applied  154  to the network interface.  
         [0029]    The techniques described above can be used with a variety of network interface components other than a network interface card. For example, the techniques may be used to tune a Local Area Network (LAN) on Motherboard (LOM) component, LAN on chipset, and/or high-speed I/O controllers such as 1,10, or 40-Gigabit Ethernet medium access controller&#39;s (MACs), SONET, or Asynchronous Transfer Mode (ATM) Controllers. The techniques may also be used in a variety of settings. For example, the automated tool can be used in determining the default settings when a component is shipped. It can also be used to test boundary conditions and implementations of new parameter settings for validation purposes.  
         [0030]    The techniques described above may be implemented in a wide variety of ways. For example, the logic may be included in a network interface component or may be performed by a device external to the component. Techniques described above may be implemented in firmware, hardware logic (e.g., an integrated circuit chip, Programmable Gate Array (PGA), Application Specific Integrated Circuit (ASIC), and so forth), software instructions, or some combination of these. For example, an implementation may feature software instructions disposed on a computer readable medium such as a magnetic storage, optical storage, or volatile or non-volatile memory device.  
         [0031]    Other implementations and variations are within the scope of the following claims.