System and method for dynamically tuning interrupt coalescing parameters

A method of dynamically adjusting one or more communication interface parameters configured to control the signaling of interrupts from a communication interface to a host processor, the method comprising:

• receiving, at a host processor:
• a first interrupt generated by the communication interface in connection with receipt of a first communication from a communication link;
• and
• a first number of communications from the communication interface, including the first communication;
• determining a workload of the communication interface;
• and
• dynamically adjusting one or more of the following parameters on the communication interface without reinitializing the communication interface:
• a first parameter configured to indicate a maximum number of communications the communication interface may accumulate before generating an interrupt to the host processor;
• and
• a second parameter configured to indicate a maximum period of time the communication interface may wait after receiving a first communication before generating an interrupt to the host processor;
• wherein said determining a workload of the communication interface comprises:
• if a fallback counter is between an initial value and a final value:
• increasing a current value of said second parameter to produce a new value for said second parameter;
• and
• decreasing said fallback counter;
• wherein said fallback counter comprises a number of interrupts;
• determining said first number;
• comparing said first number with a current value of said first parameter;
• and
• examining a trend, wherein said trend comprises a value configured to indicate a relationship between:
• the number of communications received with a previous interrupt from the communication interface;
• and
• a value of said first parameter at the time the previous interrupt was received.

A computer readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a method of dynamically adjusting one or more communication interface parameters configured to control the signaling of interrupts from a communication interface to a host processor, the method comprising:

• receiving, at a host processor, a first interrupt generated by the communication interface in connection with receipt of a first communication from a communication link;
• determining a workload of the communication interface;
• and
• dynamically adjusting one or more of the following parameters on the communication interface without reinitializing the communication interface:
• a first parameter configured to indicate a maximum number of communications the communication interface may accumulate before generating an interrupt to the host processor;
• and
• a second parameter configured to indicate a maximum period of time the communication interface may wait after receiving a first communication before generating an interrupt to the host processor;
• wherein said determining a workload of the communication interface comprises:
• determining said first number;
• comparing said first number with a current value of said first parameter;
• and
• examining a trend, wherein said trend comprises a value configured to indicate a relationship between:
• the number of communications received with a previous interrupt from the communication interface;
• and
• a value of said first parameter at the time the previous interrupt was received.

A method of dynamically adjusting interrupt coalescing parameters on a communication interface according to a pattern of communications received at the communication interface, without reinitializing the communication interface, the method comprising:

• receiving a first interrupt from the communication interface;
• identifying a first number of communications received with the first interrupt;
• comparing the first number of communications to a current value of a first parameter of the communication interface, wherein said first parameter comprises a number of communications the communication interface may accumulate before issuing an interrupt;
• examining a numerical trend configured to indicate a relationship between:
• a previous value of the first parameter at the time of a previous interrupt;
• and
• a previous number of communications received with the previous interrupt;
• adjusting said trend based on:
• said comparison of said first number of communications to said current value of said first parameter;
• and
• a current value of said trend;
• and
• if said adjusted trend is not equal to a threshold trend:
• producing a first new value for said first parameter, based on said current value of said first parameter and said trend;
• and
• dynamically updating said first parameter of the communication interface with said first new value.

A computer readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a method of dynamically adjusting interrupt coalescing parameters on a communication interface according to a pattern of communications received at the communication interface, without reinitializing the communication interface, the method comprising:

• receiving a first interrupt from the communication interface;
• identifying a first number of communications received with the first interrupt;
• comparing the first number of communications to a current value of a first parameter of the communication interface, wherein said first parameter comprises a number of communications the communication interface may accumulate before issuing an interrupt;
• examining a numerical trend configured to indicate a relationship between:
• a previous value of the first parameter at the time of a previous interrupt;
• and
• a previous number of communications received with the previous interrupt;
• adjusting said trend based on:
• said comparison of said first number of communications to said current value of said first parameter;
• and
• a current value of said trend;
• and
• if said adjusted trend is not equal to a threshold trend:
• producing a first new value for said first parameter, based on said current value of said first parameter and said trend;
• and
• dynamically updating said first parameter of the communication interface with said first new value.

A method of dynamically adjusting a network interface parameter for coalescing interrupts, the method comprising:

• receiving a first interrupt from a network interface;
• determining a number of frames, F, received in conjunction with said first interrupt;
• comparing said number of frames to a dynamic threshold, D;
• identifying a trend, T, comprising an integer representing a relationship between a number of frames received in conjunction with one or more interrupts previous to the first interrupt and the value of said dynamic threshold at the times of said one or more previous interrupts;
• if F = D;
• if T < 0, setting T = 0;
• and
• if T >= 0:
• setting D = D + T;
• incrementing T;
• and
• dynamically updating one or more parameters, on the
• network interface, that affect when the network interface may issue
• an interrupt;
• and
• if F < D:
• if T > 0, setting T = 0;
• and
• if T <= 0:
• setting D = D + T;
• decrementing T;
• and
• dynamically updating one or more parameters, on the
• network interface, that affect when the network interface may issue
• an interrupt.

A computer readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a method of dynamically adjusting a network interface parameter for coalescing interrupts, the method comprising:

• receiving a first interrupt from a network interface;
• determining a number of frames, F, received in conjunction with said first interrupt;
• comparing said number of frames to a dynamic threshold, D;
• identifying a trend, T, comprising an integer representing a relationship between a number of frames received in conjunction with one or more interrupts previous to the first interrupt and the value of said dynamic threshold at the times of said one or more previous interrupts;
• if F = D:
• if T < 0, setting T = 0;
• and
• if T >= 0:
• setting D = D + T;
• incrementing T;
• and
• dynamically updating one or more parameters, on the
• network interface, that affect when the network interface may issue
• an interrupt;
• and
• if F < D:
• if T > 0, setting T = 0;
• and
• if T <= 0:
• setting D = D + T;
• decrementing T;
• and
• dynamically updating one or more parameters, on the
• network interface, that affect when the network interface may issue
• an interrupt.

A method of dynamically adjusting one or more network interface parameters for coalescing interrupts, the method comprising:

• receiving a first interrupt from a network interface;
• if a counter>0:
• decrementing said counter;
• and
• increasing a latency, L;
• determining a number of network frames, F, received in conjunction with said first interrupt;
• comparing said number of network frames to a dynamic threshold, D;
• determining a trend, T, comprising an integer representing a relationship between a number of frames received in conjunction with one or more interrupts previous to the first interrupt and the value of said dynamic threshold at the times of said one or more previous interrupts;
• if F = D:
• if T < 0, setting T = 0;
• and
• if T >= 0:
• if D = a minimum dynamic threshold:
• setting said counter to an initial value;
• and
• setting L = a minimum latency;
• setting D = D + T;
• incrementing T;
• and
• updating one or more parameters, on the network interface,
• that affect when the network interface may issue an interrupt;
• and
• if F < D:
• if (said counter > 0) & (F = a minimum number of frames):
• setting D = said minimum dynamic threshold;
• setting L to a maximum latency;
• and
• setting T = a negative value;
• if (said counter <= 0) & (T <= 0), setting T = 0;
• and
• if [(said counter <= 0) & (T > 0)] OR [(said counter > 0) & (F >
• said minimum number of frames)]:
• setting D = D + T;
• decrementing T;
• and
• updating one or more parameters, on the network interface,
• that affect when the network interface may issue an interrupt.

A computer readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a method of dynamically adjusting one or more network interface parameters for coalescing interrupts, the method comprising:

• receiving a first interrupt from a network interface;
• if a counter>0:
• decrementing said counter;
• and
• increasing a latency, L;
• determining a number of network frames, F, received in conjunction with said first interrupt;
• comparing said number of network frames to a dynamic threshold, D;
• determining a trend, T, comprising an integer representing a relationship between a number of frames received in conjunction with one or more interrupts previous to the first interrupt and the value of said dynamic threshold at the times of said one or more previous interrupts;
• if F = D:
• if T < 0, setting T = 0;
• and
• if T >= 0:
• if D = a minimum dynamic threshold:
• setting said counter to an initial value;
• and
• setting L = a minimum latency;
• setting D = D + T;
• incrementing T;
• and
• updating one or more parameters, on the network interface,
• that affect when the network interface may issue an interrupt;
• and
• if F < D:
• if (said counter > 0) & (F = a minimum number of frames):
• setting D = said minimum dynamic threshold;
• setting L to a maximum latency;
• and
• setting T = a negative value;
• if (said counter <= 0) & (T <= 0), setting T = 0;
• and
• if [(said counter <= 0) & (T > 0)] OR [(said counter > 0) & (F >
• said minimum number of frames)]:
• setting D = D + T;
• decrementing T;
• and
• updating one or more parameters, on the network interface,
• that affect when the network interface may issue an interrupt.

An apparatus for dynamically adjusting parameters of a communication interface configured to control an interrupt coalescing behavior of the communication interface, the apparatus comprising:

• a processor;
• an interrupt handler routine executable by the processor in response to an interrupt from a communication interface;
• a first value corresponding to a first parameter of the communication interface, wherein said first parameter comprises a number of communications the communication interface may accumulate before signaling an interrupt to the processor;
• a second value corresponding to a second parameter of the communication interface, wherein said second parameter indicates a period of time the communication interface may wait before signaling an interrupt to the processor;
• and
• a trend value configured to indicate a correlation between a number of communications previously received from the communication interface and said first value when the number of communications was received;
• wherein the interrupt handler routine is configured to dynamically adjust one or more of said first value and said second value, based on a pattern of communications received at the processor from the communication interface.