Encoding and compressing bits with Write-X feature in memory system
In a computer host system, a system and method to compress the transmission between the central processing unit (CPU) and the dynamic random access memory (DRAM) of either of an extended consecutive series of ‘0’ bits or an extended consecutive series of ‘1’ bits. The CPU or a Compute Express Link (CXL) Initiator associated with the CPU identifies the consecutive strings of ‘0’ bits or ‘1’ bits. The CPU or the CXL Initiator sets data flags in a FLIT data structure, using just two bits or four bits to indicate the strings. The data structure is sent to a CXL memory, which interprets the flags and constructs the extended series of ‘0’ bits or extended series of ‘1’ bits.
1. A tangible, non-transitory, computer readable storage medium comprising instructions which, when executed by a processor of a memory system, causes the processor to execute a method comprising:
determining at a central processing unit (CPU) that a binary data stream meant for transmission to a dynamic random access memory (DRAM) contains either one of a consecutive bit stream threshold (CBS threshold) of consecutive zeros or a CBS threshold of consecutive ones; and
setting a first data flag in a Flow Control UnIT (FLIT) data structure to reflect that the binary data stream contains one of either the CBS threshold consecutive zeroes or CBS threshold consecutive ones;
wherein a data field of the FLIT is freed for carrying a CBS threshold of data comprised of a mix of zeros and ones.
2. The tangible, non-transitory, computer readable storage medium of claim 1 , wherein the method further comprises:
either setting a second data flag in the FLIT to reflect that the data stream contains the CBS threshold consecutive zeroes or setting the second data flag in the FLIT to reflect that the binary data stream contains the CBS threshold consecutive ones.
3. The tangible, non-transitory, computer readable storage medium of claim 2 , wherein the method further comprises:
receiving, at a dynamic random access memory (DRAM) device, the FLIT; and
determining at the DRAM device that the first data flag reflects that the binary data stream contains the CBS threshold number of consecutive identical bits.
4. The tangible, non-transitory, computer readable storage medium of claim 3 , wherein the method further comprises:
upon determining at the DRAM device that the first data flag reflects that the binary data stream contains the CBS threshold number of consecutive identical bits, determining from the second data flag that the data stream contains either all zeroes only or contains all ones only.
5. The tangible, non-transitory, computer readable storage medium of claim 4 , wherein the method further comprises:
constructing a data field at the DRAM device, Constructed Data, with a string of consecutive ‘0’s or a string of consecutive ‘1’s, as indicated by the second data flag.
6. The tangible, non-transitory, computer readable storage medium of claim 5 , wherein the method further comprises:
prepending at the DRAM device the Constructed Data to an Explicit Data from the FLIT header to create a Full Data Stream.
7. The tangible, non-transitory, computer readable storage medium of claim 6 , wherein the method further comprises:
writing the Full Data Stream to a memory location in DRAM as designated in the FLIT.
8. A system comprising:
a host, a host central processing unit (CPU) of the host, and a drive, wherein the host and the drive are coupled via a linker, wherein:
at least one of the CPU and an initiator of the host is configured to:
determine that a binary data stream generated by the CPU and meant for transmission to a dynamic random access memory (DRAM) of the drive contains either one of a consecutive bit stream threshold (CBS threshold) of consecutive zeros or a CBS threshold of consecutive ones; and
set a first data flag in a Flow Control UnIT (FLIT) data structure to reflect that the binary data stream the CBS threshold number of consecutive identical bits only;
wherein a data field of the FLIT is freed for carrying a CBS threshold of data comprised of a mix of zeros and ones.
9. The system of claim 8 , wherein the at least one of the CPU and the initiator is further configured to:
set a second data flag in the FLIT to reflect that the binary data stream contains consecutive zeroes only or setting the second data flag in the FLIT to reflect that the binary data stream contains consecutive ones only.
10. The system of claim 9 , wherein the drive is configured to:
receive the FLIT; and determine that the first data flag reflects that the binary data stream contains the CBS threshold number of consecutive identical bits.
11. The system of claim 10 , wherein:
upon determining at the drive that the first data flag reflects that the data stream contains the CBS threshold number of consecutive identical bits, the drive is configured to determine from the second data flag that the data stream contains either only zeroes or only ones.
12. The system of claim 11 , wherein:
the drive constructs a Constructed Data with a string of consecutive ‘0’s or a string of consecutive ‘1’s, as indicated by the second data flag.
13. The system of claim 12 , wherein the drive prepends the Constructed Data to an Explicit Data from the FLIT header to create a Full Data Stream.
14. The system of claim 13 , wherein the drive writes the Full Data Stream to a memory location in DRAM as designated in the FLIT.