International Business Machines Corporation

Moinuddin K Qureshi

Michele M Franceschini

Ashish Jagmohan

Luis Alfonso Lastras-Montano

Kyu-hyoun Kim

Hillery C Hunter

Charles Arthur Kilmer

Alper Buyuktosunoglu

Pradip Bose

Luis A Lastras

Jeonghee Shin

John A Darringer

John Peter Karidis

John Steven Dodson

Balaram Sinharoy

Bulent Abali

Vijayalakshmi Srinivasan

Kerry Bernstein

Philip George Emma

Eren Kursun

Victor V Zyuban

Christopher J Gonzalez

An aspect of this invention is a method for providing a PreSET region in a memory device wherein the PreSET region includes one or more lines of the memory device which have been PreSET; performing a write operation on one or more out of place lines of the memory device by writing to the PreSET region instead of writing to an in place line of the memory device; and storing in an indirection table a mapping of each of a respective plurality of logical pages of the memory device to a corresponding physical page of a plurality of physical pages of the memory device, wherein the indirection table keeps track of the one or more out of place lines.

Out-of-place presetting based on indirection table

A computer cache memory organization called Probabilistic Set Associative Cache (PAC) has the hardware complexity and latency of a direct-mapped cache but functions as a set-associative cache for a fraction of the time, thus yielding better than direct mapped cache hit rates. The organization is considered a (1+P)-way set associative cache, where the chosen parameter called Override Probability P determines the average associativity, for example, for P=0.1, effectively it operates as if a 1.1-way set associative cache.

Probabilistic associative cache

Techniques are presented that include determining, for data to be written to a nonvolatile memory, a location in the nonvolatile memory to which the data should be written based at least on one or more wear metrics corresponding to the location. The one or more wear metrics are based on measurements of the location. The measurements estimate physical wear of the location. The techniques further include writing the data to the determined location in the nonvolatile memory. The techniques may be performed by methods, apparatus (e.g., a memory controller), and computer program products.

Variability aware wear leveling

A computer cache memory organization called Probabilistic Set Associative Cache (PAC) has the hardware complexity and latency of a direct-mapped cache but functions as a set-associative cache for a fraction of the time, thus yielding better than direct mapped cache hit rates. The organization is considered a (1+P)&#x2014;way set associative cache, where the chosen parameter called Override Probability P determines the average associativity, for example, for P=0.1, effectively it operates as if a 1.1-way set associative cache.

Errors on a dynamic random access memory ('DRAM') having an error correcting decoder ('ECC') can be detected by the ECC when reading a row of the DRAM. The ECC includes error correcting code logic. If errors are detected that cannot be corrected by the ECC logic, test control logic determines weak cell information for the row, evaluates the errors using the weak cell information, and may correct the errors. The weak cell information may include weak cell locations and failure values.

DRAM error detection, evaluation, and correction

A refresh of a DRAM having at least a fast and a slow refresh rate includes encoding a pointer on a row or rows with refresh information, reading the refresh information, and incrementing a fast refresh address counter with the refresh information. The refresh may be performed by encoding one or more cells on a row that may require a fast refresh, one or more cells on a group of rows that may require a fast refresh, or one or more cells on a row that may not require a fast refresh.

DRAM refresh

This disclosure includes a method for preventing errors in a DRAM (dynamic random access memory) due to weak cells that includes determining the location of a weak cell in a DRAM row, receiving data to write to the DRAM, and encoding the data into a bit vector to be written to memory. For each weak cell location, the corresponding bit from the bit vector is equal to the reliable logic state of the weak cell and the bit vector is longer than the data.

Managing errors in a DRAM by weak cell encoding

A dynamic system coupled with 'pre-Silicon' design methodologies and 'post-Silicon' current optimizing programming methodologies to improve and optimize current delivery into a chip, which is limited by the physical properties of the connections (e.g., Controlled Collapse Chip Connection or C4s). The mechanism consists of measuring or estimating power consumption at a certain granularity within a chip, converting the power information into C4 current information using a method, and triggering throttling mechanisms (including token based throttling) where applicable to limit the current delivery per C4 beyond pre-established limits or periods. Design aids are used to allocate C4s throughout the chip based on the current delivery requirements. The system coupled with design and programming methodologies improve and optimize current delivery is extendable to connections across layers in a multilayer 3D chip stack.

Adaptive workload based optimizations coupled with a heterogeneous current-aware baseline design to mitigate current delivery limitations in integrated circuits

This disclosure includes a method for correcting errors on a DRAM having an ECC which includes writing data to a DRAM row, reading data from the DRAM row, detecting errors in the data that cannot be corrected by the DRAM's ECC, determining erasure information for the row, evaluating the errors using the erasure information, and correcting the errors in the data.

Memory cell presetting for improved performance including a method for using a computer system to identify a region in a memory. The region includes a plurality of memory cells characterized by a write performance characteristic that has a first expected value when a write operation changes a current state of the memory cells to a desired state of the memory cells and a second expected value when the write operation changes a specified state of the memory cells to the desired state of the memory cells. The second expected value is closer than the first expected value to a desired value of the write performance characteristic. The plurality of memory cells in the region are set to the specified state, and the data is written into the plurality of memory cells responsive to the setting.

Memory cell presetting for improved memory performance

Current-aware floorplanning to overcome current delivery limitations in integrated circuits

A method for determining an optimized refresh rate involves testing a refresh rate on rows of cells, determining an error rate of the rows, evaluating the error rate of the rows; and repeating these steps for a decreased refresh rate until the error rate is greater than a constraint, at which point a slow refresh rate is set.

Method for optimizing refresh rate for DRAM

A system and method of operating an integrated circuit (IC) having a fixed layout of one or more blocks having one or more current sources therein that draw electrical current from a power source. The method includes dynamically issuing to a block configured to perform operations responsive to an instruction received at the block, a reserve amount of tokens; determining for each issuance of instruction to the block whether that block's reserve token amount exceeds zero; and one of: issuing the instruction to the block if the token reserve for that block is greater than one, and decrementing, after issuance of the instruction, by one token the block's reserve token amount, or, preventing issuance of an instruction to the block. In the method, each block may be initialized to have: a reserve token amount of zero, a token expiration period; a token generation cycle and a token generation amount.

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White Plains, NY, United States of America

Moinuddin K Qureshi