System and method for assigning memory access transfers between communication channels
View Patent ↗A communication channel controller includes a queue, a memory map, and a scheduler. The queue to store a first memory transfer request received at the communication channel controller. The memory map stores information to identify a memory address range to be associated with a memory. The scheduler to compare a source address of the first memory transfer in the queue to the memory address range in the memory map to determine whether the source address of the first memory transfer request targets the memory, and in response allocate the first memory transfer request to a first communication channel of a plurality of communication channels in response to the first communication channel having all of its outstanding memory transactions to a common source address bank and source address page as a source address bank and a source address page of the first memory transfer request.
1. A method comprising:
receiving a first memory transfer request at a communication channel controller;
comparing a source address bank and a source address page of the first memory transfer request to source address banks and source address pages of outstanding memory transactions on a first communication channel;
allocating the first memory transfer request to the first communication channel of a plurality of communication channels in response to determining that the first communication channel has all of its outstanding memory transactions to a common source address bank and source address page as the source address bank and the source address page of the first memory transfer request;
receiving a second memory transfer request at the communication channel controller; and
comparing a source address bank and a source address page of the second memory transfer request to source address banks and source address pages of the outstanding memory transactions on the second communication channel;
allocating the second memory transfer request to a second communication channel of the plurality of communication channels in response to determining that the second communication channel having no outstanding memory transactions with a source address bank that is the same as the source address bank of the second memory transfer request but a source address page that is different than the source address page of the second memory transfer request.
2. The method of claim 1 further comprising:
receiving a third memory transfer request at the communication channel controller; and
allocating the third memory transfer request to a third communication channel of the plurality of communication channels in response to the third communication channel having an outstanding transaction that is page colliding with the third memory transfer and also has more cycles to elapse prior to the third memory transfer request being assigned to the third communication channel than any other communication channel of the plurality of communication channels.
3. The method of claim 2 wherein the outstanding transaction that is page colliding with the third memory transfer comprises a source address bank that is the same as a source address bank of the third memory transfer but a source address page that is different than the source address page of the third memory transfer.
4. The method of claim 1 further comprising:
determining that the first memory transfer request identifies a double data rate memory as a source of the first memory transfer request prior to said allocating the first memory transfer to the first communication channel.
5. The method of claim 4 wherein an outstanding memory transaction is selected from a group comprising: a second memory transfer request waiting to be sent to the double data rate memory, and an outstanding read response associated with the second memory transfer request sent to the double data rate memory.
6. The method of claim 1 wherein an order of a plurality of memory transfers sent along a communication channel from the communication channel controller is required to be maintained when read responses associated with the plurality of memory transfers are received at the communication channel controller along the communication channel.
7. A communication channel controller comprising:
a plurality of communication channels communicatively coupled to a memory external to the communication channel controller, wherein the memory comprises source address banks and source address pages;
a scheduler, communicatively coupled to the plurality of communication channels, the scheduler configured to
receive a first memory transfer request,
compare a source address bank and a source address page of the first memory transfer request to source address banks and source address pages of outstanding memory transactions on a first communication channel of the plurality of communication channels,
allocate the first memory transfer request to the first communication channel of the plurality of communication channels in response to a determination that the first communication channel has all of its outstanding memory transactions to a common source address bank and source address page as the source address bank and the source address page of the first memory transfer request;
receive a second memory transfer request,
compare a source address bank and a source address page of the second memory transfer request to source address banks and source address pages of the outstanding memory transactions on a second communication channel of the plurality of communication channels, and
allocate the second memory transfer request to the second communication channel of the plurality of communication channels in response to a determination that the second communication channel has no outstanding memory transactions with a source address bank that is the same as the source address bank of the second memory transfer request but a source address page that is different than the source address page of the second memory transfer request.
8. The communication channel controller of claim 7 , wherein the scheduler is further configured to
receive a third memory transfer request, and
allocate the third memory transfer request to a third communication channel of the plurality of communication channels in response to the third communication channel having an outstanding transaction that is page colliding with the third memory transfer and also has more cycles to elapse prior to the third memory transfer request being assigned to the third communication channel than any other communication channel of the plurality of communication channels.
9. The communication channel controller of claim 8 wherein the outstanding transaction that is page colliding with the third memory transfer comprises a source address bank that is the same as a source address bank of the third memory transfer but a source address page that is different than the source address page of the third memory transfer.
10. The communication channel controller of claim 7 wherein an outstanding transaction is selected from a group comprising:
a second memory transfer request waiting to be sent to the memory, and
an outstanding read response associated with the second memory transfer request sent to the memory.
11. The communication channel controller of claim 7 wherein an order of a plurality of memory transfers sent along a communication channel from the communication channel controller is required to be maintained when read responses associated with the plurality of memory transfers are received at the communication channel controller along the communication channel.
12. The communication channel controller of claim 7 wherein the memory comprises a double data rate memory, and the communication channel controller further comprising:
a direct memory access engine, communicatively coupled to the scheduler, the direct memory access engine configured to
send the first memory transfer request to the double data memory via the first communication channel of the plurality of communication channels, and
record the source address bank and page of the first memory transfer request for the first memory transfer request as an outstanding transaction for the first communication channel of the plurality of communication channels.
13. The communication channel controller of claim 7 , wherein an outstanding memory transaction is a transaction selected from a group comprising: a second memory transfer request waiting to be sent to the double data rate memory, and an outstanding read response associated with the third memory transfer request sent to the double data rate memory.
14. The communication channel controller of claim 13 , wherein the outstanding read response associated with the third memory transfer request sent to the double data rate memory.
15. A communication channel controller comprising:
a plurality of communication channels;
a memory to store a queue configured to store a first memory transfer request received at the communication channel controller, and to store a second memory transfer request received at the communication channel controller;
a memory map storing information to identify a memory address range to be associated with a type of memory; and
a scheduler communicatively coupled to the queue, to the memory map, and to the plurality of communication channels, the scheduler configured to compare a source address of the first memory transfer request in the queue to the memory address range in the memory map to determine whether the source address of the first memory transfer request target the type of memory, to compare a source address bank and source address page of the first memory transfer request to source address banks and source address pages of outstanding memory transactions on a first communication channel of the plurality of communication channels, and to allocate the first memory transfer request to the first communication channel of the plurality of communication channels in response to the first communication channel having all of its outstanding memory transactions to a common source address bank and source address page as the source address bank and the source address page of the first memory transfer request, and the scheduler is further configured to compare a source address of the second memory transfer in the queue to the memory address range in the memory map to determine whether the source address of the second memory transfer request targets the memory, to compare a source address bank and source address page of the second memory transfer request to source address banks and source address pages of outstanding memory transactions on a second communication channel of the plurality of communication channels, and to allocate the second memory transfer request to the second communication channel of the plurality of communication channels in response to the second communication channel having no outstanding memory transactions with a source address bank that is the same as the source address bank of the second memory transfer request but the source address page that is different than a source address page of the second memory transfer request.
16. The communication channel controller of claim 15 further comprising:
an address decoder communicatively coupled to the scheduler, the address decoder configured to generate the source address bank and the source address page of the first memory transfer request and provide the source address bank and the source address page of the first memory transfer request to the scheduler.
17. The communication channel controller of claim 15 further comprising:
a prefetcher communicatively coupled to the scheduler, the prefetcher configured to retrieve information and other attributes for the first memory transfer request and provide the information and the other attributes to the scheduler.
18. The communication channel controller of claim 15 further comprising:
a direct memory access engine communicatively coupled to the scheduler, the direct memory access engine configured to send the first memory transfer request to a double data rate memory via the first communication channel of the plurality of communication channels, and record the source address bank and page of the first memory transfer request for the first memory transfer request as an outstanding transaction for the first communication channel of the plurality of communication channels.
19. The communication channel controller of claim 15 , wherein the queue is further configured to store a third memory transfer request, and the scheduler is further configured to compare a source address of the third memory transfer in the queue to the memory address range in the memory map to determine whether the source address of the third memory transfer request targets the memory, and in response allocate the third memory transfer request to a third communication channel of the plurality of communication channels in response to the third communication channel having an outstanding transaction that is page colliding with the third memory transfer and also has more cycles to elapse prior to the third memory transfer request being assigned to the third communication channel than any other communication channel of the plurality of communication channels.
20. The communication channel controller of claim 15 , wherein an outstanding memory transaction is a transaction selected from a group comprising: a third memory transfer request waiting to be sent to a double data rate memory, and an outstanding read response associated with the third memory transfer request sent to the double data rate memory.