US 2004/0064664 A1 · Buffer management architecture and method for an infiniband subnetwork

Abstract

An architecture and method for dynamically allocating and deallocating memory for variable length packets with a variable number of virtual lanes in an Infiniband subnetwork. This architecture uses linked lists and tags to handle the variable number of virtual Lanes and the variable packet sizes. The memory allocation scheme is independent of Virtual Lane allocation and the maximum Virtual Lane depth. The disclosed architecture is also able to process Infiniband packet data comprising variable packet lengths, a fixed memory allocation size, and deallocation of memory when packets are either multicast or unicast. The memory allocation scheme uses linked lists to perform memory allocation and deallocation, while tags are used to track Infiniband subnetwork and switch-specific issues. Memory allocation and deallocation is performed using several data and pointer tables. These tables store packet data information, packet buffer address information, and pointer data and point addresses. The tags allow the memory allocation and deallocation process to correctly handle good and bad packets, as well as successive blocks within a data packet.

Claims34

Dependent claims

An architecture for the allocation and deallocation of buffer memory associated with a variable number of one or more Virtual Lanes (VL's) in a subnetwork, wherein said buffer memory is allocated and deallocated using blocks of one or more credits while said buffer memory is stored in increments of a word, and the one or more credits are allocated and deallocated using a variable length packet size, further comprising:

a linked list, operable to track the allocation and deallocation of the buffer memory among the one or more VL's;
a first table, operable to store one or more words associated with the buffer memory;
a second table, operable to store the linked list, said second table comprising:
one or more pointer addresses, each pointer address corresponding to one credit of the buffer memory and a tag address;
one or more pointer data words, each pointer data word of the one or more pointer data words containing the address of the next pointer word in the linked list;
a third table, operable to store one or more tag words, each tag word of the one or more tag words corresponding to one credit in the buffer memory and each tag word of the one or more tag words further comprising one or more of:
one or more tag addresses corresponding to a pointer address
and the one credit of buffer memory;
a field indicating the packet is good or bad;
a field containing the VL identifier associated with the packet;
a field containing the number of grants associated with the packet;
a field containing the packet start address;
a field corresponding to the packet length;
and
a field that distinguishes a continuation tag from a start tag.

12 more elements

A method for the allocation and deallocation of buffer memory associated with a variable number of one or more Virtual Lanes (VL's) in a subnetwork, wherein said buffer memory is allocated and deallocated using blocks of one or more credits while said buffer memory is stored in increments of a word, and the one or more credits are allocated and deallocated using a variable length packet size, further comprising:

creating one or more storage elements, operable to store:
one or more words associated with the buffer memory;
a linked list and associated pointer information;
one or more tag words, each tag word of the one or more tag words corresponding to one credit in the buffer memory;
an allocation phase, further comprising:
receiving a packet, comprising one or more credits, from the subnetwork;
reading one or more fields of a tag in a header contained in a first credit of the one or more credits of the packet and whereupon if the tag indicates the packet is correct placing the first credit in the buffer memory and a start tag in the tag table;
if the packet is correct generating one or more continuation tags of each subsequent credit of the one or more credits of the packet wherein said one or more credits are placed in memory and the one or more continuation tags are placed in the tag table;
updating the linked list to reflect the packets and the one or more credits placed in memory;
a deallocation phase, further comprising:
reading a tag of a packet of one or more packets stored in the buffer memory, wherein if a grant field of the tag is a maximum grant value allowed, the memory associated with the packet is deallocated, further comprising updating the linked list to reflect the absence of the packet in the buffer memory.

8 more elements

a setup phase, further comprising:
assigning the buffer memory among the one or more VL's;
creating a first table, operable to store one or more words associated with the buffer memory;
creating a second table, operable to store a linked list that tracks allocation of buffer memory among the one or more VL's, said second table comprising:
one or more pointer addresses, each pointer address corresponding to one credit of the buffer memory;
one or more pointer data words, each pointer data word of the one or more pointer data words containing the address of the next pointer word in the linked list;
creating a third table, operable to store one or more tag words, each tag word of the one or more tag words corresponding to one credit in the buffer memory and each tag word of the one or more tag words further comprising one or more of:
a packet input VL;
a packet buffer type code;
a number of times packet has been transferred through the subnetwork;
initializing a free list head to a 0 pointer address of the one or more pointer addresses;
initializing a free list tail to a maximum pointer address of the one or more pointer addresses;
an allocation phase, further comprising:
receiving a packet, comprising one or more credits, from the subnetwork;
reading a packet header comprising a start tag contained in a first credit of the one or more credits of the packet and determining if the packet is correct, whereupon if the packet is correct further comprising;
placing the first credit in the buffer memory and initializing a pointer address of the one or more pointer addresses;
writing a tag associated with each credit of the one or more credits;
reading a continuation tag of each subsequent credit of the one or more credits of the packet wherein said one or more credits are placed in memory in accordance with the address of the free list head and the address of the free list tail;
updating the free list head to point to a next available input buffer address;
updating the free list tail to point to a new maximum pointer address;
a deallocation phase, further comprising:
reading a tag of a packet of one or more packets stored in the buffer memory, wherein if a grant field of the tag is a maximum grant value allowed, the memory associated with the packet is to be deallocated, further comprising;
updating the free list tail to be an address of a first pointer in the packet;
as each credit of the packet is transferred, setting the free list tail to the address mod 4 of the credit to be transferred;
and
deallocating memory using the free list head so assigned.

23 more elements

Dependencies are inferred from the claim text.

Buffer management architecture and method for an infiniband subnetwork

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Buffer management architecture and method for an infiniband subnetwork

Life of this patent

Abstract

Claims34