NDIS_RECEIVE_THROTTLE_PARAMETERS structure (ndis.h)

The NDIS_RECEIVE_THROTTLE_PARAMETERS structure specifies the maximum number of NET_BUFFER_LIST structures that a miniport driver should indicate in a deferred procedure call (DPC).

Syntax

typedef struct _NDIS_RECEIVE_THROTTLE_PARAMETERS {
  ULONG MaxNblsToIndicate;
  ULONG MoreNblsPending : 1;
} NDIS_RECEIVE_THROTTLE_PARAMETERS, *PNDIS_RECEIVE_THROTTLE_PARAMETERS;

Members

MaxNblsToIndicate

The maximum number of NET_BUFFER_LIST structures that a miniport driver should include in a receive indication. If this value is NDIS_INDICATE_ALL_NBLS, the miniport can indicate all of the NET_BUFFER_LIST structures that it has.

MoreNblsPending

A value that, when TRUE, specifies that the miniport driver has NET_BUFFER_LIST structures pending after it processed the maxim number or structures that NDIS requested in the MaxNblsToIndicate member.

Note  If NDIS set the MaxNblsToIndicate member to NDIS_INDICATE_ALL_NBLS, the miniport driver should set MoreNblsPending to FALSE before it returns from the DPC.

 

Remarks

The ReceiveThrottleParameters parameters of the MiniportInterruptDPC and the MiniportMessageInterruptDPC DPC handler functions point to an NDIS_RECEIVE_THROTTLE_PARAMETERS structure. This structure specifies the parameters of Receive Side Throttle (RST) in NDIS 6.20 and later.

On entry to the DPC handler, the MaxNblsToIndicate member of the NDIS_RECEIVE_THROTTLE_PARAMETERS structure specifies the maximum number of NET_BUFFER_LIST structures that the miniport driver should indicate in the DPC. If this value is NDIS_INDICATE_ALL_NBLS, the miniport driver can indicate all of the NET_BUFFER_LIST structures that it has in its queues.

After the miniport driver processes the specified maximum number of NET_BUFFER_LIST structures, the miniport driver might have more packets in its receive queues. In this case, the miniport driver should set the MoreNblsPending member to TRUE and it should not re-enable interrupts before it returns from the DPC. This is true for both line-based and message biased interrupts.

The miniport driver should follow these guidelines when the MaxNblsToIndicate member is set to NDIS_INDICATE_ALL_NBLS:

• A value of NDIS_INDICATE_ALL_NBLS allows the miniport driver to determine the number of NET_BUFFER_LIST structures that it indicates in a DPC call. This gives the miniport driver the following options:
  • The miniport driver can indicate all of its pending NET_BUFFER_LIST structures from its receive queues.
  • The miniport driver can limit the number of NET_BUFFER_LIST structures that it indicates based on its heuristics to avoid spending an excessive amount of time within a DPC call.

    In particular, the driver should use its heuristics to avoid a DPC timeout, which is the maximum amount of time the driver can spend in its DPC. When the timeout interval expires, a bugcheck occurs on the system. Starting with Windows 7, the DPC timeout is 10 seconds.

• The miniport driver should set MoreNblsPending to FALSE before it returns from the DPC. The driver should do this regardless of whether it has pending NET_BUFFER_LIST structures in its receive queues that have not been indicated.

If the miniport driver is using line-based interrupts or a single MSI message, it should do interrupt-processing for all of the interrupt sources that it has. If there are packets in the receive queue, it should indicate at most MaxNblsToIndicate NET_BUFFER_LIST structures to NDIS with the NdisMIndicateReceiveNetBufferLists function.

If the miniport driver is using multiple MSI messages to differentiate different interrupt sources, it should ignore the ReceiveThrottleParameters member for MSI messages that are not associated with receive indications. For receive interrupt messages, the miniport driver should indicate at most MaxNblsToIndicate NET_BUFFER_LIST structures.

Note  If the miniport driver sets MoreNblsPending, NDIS will call the DPC again. However, the amount of time that passes before the next DPC call is not defined. Also, the amount of time between the initial interrupt service routing (ISR) returns and the DPC is not defined. After the miniport driver sets MoreNblsPending, it should handle the next DPC as it handled the first DPC.

 

Requirements

Requirement	Value
Minimum supported client	Supported in NDIS 6.20 and later.
Header	ndis.h (include Ndis.h)

See also

MiniportInterruptDPC

MiniportMessageInterruptDPC

NET_BUFFER_LIST

NdisMIndicateReceiveNetBufferLists