Patents by Inventor Arvind Mithal
Arvind Mithal has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8350594Abstract: Enabling scheduling of single cycle as well as scheduling multi-cycle rules in a synchronous digital system whose behavior is governed by an asynchronous system specification (e.g., a TRS) provides a way to allow complex actions at state transitions of the asynchronous system without requiring that the complex actions be synthesized in logic that must be performed in a single clock cycle. For example, a relatively infrequent action may include a critical timing path that determines the maximum clock frequency of the system. By allowing that infrequent action to take multiple clock cycles, even if that action takes more absolute time, other actions may take less absolute time by virtue of being able to operate the synchronous system at a higher clock rate. The overall system may then operate more quickly (e.g., as measured by the average number of rules applied per unit of absolute time).Type: GrantFiled: November 9, 2009Date of Patent: January 8, 2013Assignee: Massachusetts Institute of TechnologyInventors: Michal Karczmarek, Arvind Mithal, Muralidaran Vijayaraghavan
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Patent number: 8108810Abstract: A method for specifying and synthesizing a synchronous digital circuit by first accepting a specification of an asynchronous system in which stored values are updated according to a set of state transition rules. For instance, the state transition rules are specified as a Term Rewriting System (TRS) in which each rule specifies a number of allowable state transitions, and includes a logical precondition on the stored values and a functional specification of the stored values after a state transition in terms of the stored values prior to the state transition. The specification of the asynchronous circuit is converted into a specification of a synchronous circuit in which a number of state transitions can occur during each clock period.Type: GrantFiled: February 23, 2009Date of Patent: January 31, 2012Assignee: Massachusetts Institute of TechnologyInventors: James C Hoe, Arvind Mithal
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Patent number: 7724760Abstract: A method for selecting a queue for service across a shared link. The method includes classifying each queue from a group of queues within a plurality of ingresses into one tier of a number āNā of tiers. The number āNā is greater than or equal to 2. Information about allocated bandwidth is used to classify at least some of the queues into the tiers. Each tier is assigned a different priority. The method also includes matching queues to available egresses by matching queues classified within tiers with higher priorities before matching queues classified within tiers with lower priorities.Type: GrantFiled: August 12, 2003Date of Patent: May 25, 2010Assignee: Broadcom CorporationInventors: Hari Balakrishnan, Srinivas Devadas, Arvind Mithal
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Publication number: 20100117683Abstract: Enabling scheduling of single cycle as well as scheduling multi-cycle rules in a synchronous digital system whose behavior is governed by an asynchronous system specification (e.g., a TRS) provides a way to allow complex actions at state transitions of the asynchronous system without requiring that the complex actions be synthesized in logic that must be performed in a single clock cycle. For example, a relatively infrequent action may include a critical timing path that determines the maximum clock frequency of the system. By allowing that infrequent action to take multiple clock cycles, even if that action takes more absolute time, other actions may take less absolute time by virtue of being able to operate the synchronous system at a higher clock rate. The overall system may then operate more quickly (e.g., as measured by the average number of rules applied per unit of absolute time).Type: ApplicationFiled: November 9, 2009Publication date: May 13, 2010Applicant: Massachusetts Institute of TechnologyInventors: Michal Karczmarek, Arvind Mithal, Muralidaran Vijayaraghavan
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Patent number: 7716608Abstract: A scheduling approach enables scheduling sequential execution of rules in a single cycle of a synchronous system without necessarily requiring explicit implementation of a composite rule for each sequence of rules than may be composed. One method for designing a synchronous digital system includes using modules with multiple successive interfaces such that within the a single clocked cycle, each module performs a function equivalent to completing interactions through one of its interfaces before performing interactions through any succeeding one of its interfaces. The scheduled state transition rules are associated with corresponding interfaces of the modules.Type: GrantFiled: June 1, 2006Date of Patent: May 11, 2010Assignee: Massachusetts Institute of TechnologyInventors: Arvind Mithal, Daniel L. Rosenband
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Publication number: 20090268628Abstract: A method for specifying and synthesizing a synchronous digital circuit by first accepting a specification of an asynchronous system in which stored values are updated according to a set of state transition rules. For instance, the state transition rules are specified as a Term Rewriting System (TRS) in which each rule specifies a number of allowable state transitions, and includes a logical precondition on the stored values and a functional specification of the stored values after a state transition in terms of the stored values prior to the state transition. The specification of the asynchronous circuit is converted into a specification of a synchronous circuit in which a number of state transitions can occur during each clock period.Type: ApplicationFiled: February 23, 2009Publication date: October 29, 2009Applicant: Massachusetts Institute of TechnologyInventors: James C. Hoe, Arvind Mithal
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Patent number: 7392352Abstract: A computer architecture that includes a hierarchical memory system and one or more processors. The processors execute memory access instructions whose semantics are defined in terms of the hierarchical structure of the memory system. That is, rather than attempting to maintain the illusion that the memory system is shared by all processors such that changes made by one processor are immediately visible to other processors, the memory access instructions explicitly address access to a processor-specific memory, and data transfer between the processor-specific memory and the shared memory system. Various alternative embodiments of the memory system are compatible with these instructions. These alternative embodiments do not change the semantic meaning of a computer program which uses the memory access instructions, but allow different approaches to how and when data is actually passed from one processor to another.Type: GrantFiled: July 7, 2005Date of Patent: June 24, 2008Assignee: Massachusetts Institute of TechnologyInventors: Arvind Mithal, Xiaowei Shen, Lawrence Rogel
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Publication number: 20060277021Abstract: A scheduling approach enables scheduling sequential execution of rules in a single cycle of a synchronous system without necessarily requiring explicit implementation of a composite rule for each sequence of rules than may be composed. One method for designing a synchronous digital system includes using modules with multiple successive interfaces such that within the a single clocked cycle, each module performs a function equivalent to completing interactions through one of its interfaces before performing interactions through any succeeding one of its interfaces. The scheduled state transition rules are associated with corresponding interfaces of the modules.Type: ApplicationFiled: June 1, 2006Publication date: December 7, 2006Inventors: Arvind Mithal, Daniel Rosenband
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Publication number: 20060004967Abstract: A computer architecture that includes a hierarchical memory system and one or more processors. The processors execute memory access instructions whose semantics are defined in terms of the hierarchical structure of the memory system. That is, rather than attempting to maintain the illusion that the memory system is shared by all processors such that changes made by one processor are immediately visible to other processors, the memory access instructions explicitly address access to a processor-specific memory, and data transfer between the processor-specific memory and the shared memory system. Various alternative embodiments of the memory system are compatible with these instructions. These alternative embodiments do not change the semantic meaning of a computer program which uses the memory access instructions, but allow different approaches to how and when data is actually passed from one processor to another.Type: ApplicationFiled: July 7, 2005Publication date: January 5, 2006Inventors: Arvind Mithal, Xiaowei Shen, Lawrence Rogel
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Patent number: 6977907Abstract: A method for specifying and synthesizing a synchronous digital circuit by first accepting a specification of an asynchronous system in which stored values are updated according to a set of state transition rules. For instance, the state transition rules are specified as a Term Rewriting System (TRS) in which each rule specifies a number of allowable state transitions, and includes a logical precondition on the stored values and a functional specification of the stored values after a state transition in terms of the stored values prior to the state transition. The specification of the asynchronous circuit is converted into a specification of an synchronous circuit in which a number of state transitions can occur during each clock period.Type: GrantFiled: July 22, 2003Date of Patent: December 20, 2005Assignee: Massachusetts Institute of TechnologyInventors: Arvind Mithal, James C. Hoe
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Publication number: 20050254436Abstract: A method for specifying and synthesizing a synchronous digital circuit by first accepting a specification of an asynchronous system in which stored values are updated according to a set of state transition rules. For instance, the state transition rules are specified as a Term Rewriting System (TRS) in which each rule specifies a number of allowable state transitions, and includes a logical precondition on the stored values and a functional specification of the stored values after a state transition in terms of the stored values prior to the state transition. The specification of the asynchronous circuit is converted into a specification of a synchronous circuit in which a number of state transitions can occur during each clock period.Type: ApplicationFiled: May 31, 2005Publication date: November 17, 2005Inventors: James Hoe, Arvind Mithal
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Patent number: 6901055Abstract: A method for specifying and synthesizing a synchronous digital circuit by first accepting a specification of an asynchronous system in which stored values are updated according to a set of state transition rules. For instance, the state transition rules are specified as a Term Rewriting System (TRS) in which each rule specifies a number of allowable state transitions, and includes a logical precondition on the stored values and a functional specification of the stored values after a state transition in terms of the stored values prior to the state transition. The specification of the asynchronous circuit is converted into a specification of a synchronous circuit in which a number of state transitions can occur during each clock period.Type: GrantFiled: August 18, 2000Date of Patent: May 31, 2005Assignee: Massachusetts Institute of TechnologyInventors: James C. Hoe, Arvind Mithal
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Patent number: 6757787Abstract: A methodology for designing a distributed shared-memory system, which can incorporate adaptation or selection of cache protocols during operation, guarantees semantically correct processing of memory instructions by the multiple processors. A set of rules includes a first subset of “mandatory” rules and a second subset of “voluntary” rules such that correct operation of the memory system is provided by application of all of the mandatory rules and selective application of the voluntary rules. A policy for enabling voluntary rules specifies a particular coherent cache protocol. The policy can include various types of adaptation and selection of different operating modes for different addresses and at different caches. A particular coherent cache protocol can make use of a limited capacity directory in which some but not necessarily all caches that hold a particular address are identified in the directory.Type: GrantFiled: December 19, 2002Date of Patent: June 29, 2004Assignee: Massachusetts Institute of TechnologyInventors: Xiaowei Shen, Arvind Mithal, Lawrence Rogel
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Publication number: 20040090974Abstract: A method for selecting a queue for service across a shared link. The method includes classifying each queue from a group of queues within a plurality of ingresses into one tier of a number “N” of tiers. The number “N” is greater than or equal to 2. Information about allocated bandwidth is used to classify at least some of the queues into the tiers. Each tier is assigned a different priority. The method also includes matching queues to available egresses by matching queues classified within tiers with higher priorities before matching queues classified within tiers with lower priorities.Type: ApplicationFiled: August 12, 2003Publication date: May 13, 2004Applicant: Sandburst CorporationInventors: Hari Balakrishnan, Srinivas Devadas, Arvind Mithal
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Publication number: 20040093467Abstract: A methodology for designing a distributed shared-memory system, which can incorporate adaptation or selection of cache protocols during operation, guarantees semantically correct processing of memory instructions by the multiple processors. A set of rules includes a first subset of “mandatory” rules and a second subset of “voluntary” rules such that correct operation of the memory system is provided by application of all of the mandatory rules and selective application of the voluntary rules. A policy for enabling voluntary rules specifies a particular coherent cache protocol. The policy can include various types of adaptation and selection of different operating modes for different addresses and at different caches. A particular coherent cache protocol can make use of a limited capacity directory in which some but not necessarily all caches that hold a particular address are identified in the directory.Type: ApplicationFiled: December 19, 2002Publication date: May 13, 2004Applicant: Massachusetts Institute of Technology, a Massachusetts corporationInventors: Xiaowei Shen, Arvind Mithal, Lawrence Rogel
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Publication number: 20040083343Abstract: A computer architecture that includes a hierarchical memory system and one or more processors. The processors execute memory access instructions whose semantics are defined in terms of the hierarchical structure of the memory system. That is, rather than attempting to maintain the illusion that the memory system is shared by all processors such that changes made by one processor are immediately visible to other processors, the memory access instructions explicitly address access to a processor-specific memory, and data transfer between the processor-specific memory and the shared memory system. Various alternative embodiments of the memory system are compatible with these instructions. These alternative embodiments do not change the semantic meaning of a computer program which uses the memory access instructions, but allow different approaches to how and when data is actually passed from one processor to another.Type: ApplicationFiled: October 21, 2003Publication date: April 29, 2004Applicant: Massachusetts Institute of Technology, a Massachusetts corporationInventors: Arvind Mithal, Xiaowei Shen, Lawrence Rogel
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Publication number: 20040052215Abstract: A method for specifying and synthesizing a synchronous digital circuit by first accepting a specification of an asynchronous system in which stored values are updated according to a set of state transition rules. For instance, the state transition rules are specified as a Term Rewriting System (TRS) in which each rule specifies a number of allowable state transitions, and includes a logical precondition on the stored values and a functional specification of the stored values after a state transition in terms of the stored values prior to the state transition. The specification of the asynchronous circuit is converted into a specification of an synchronous circuit in which a number of state transitions can occur during each clock period.Type: ApplicationFiled: July 22, 2003Publication date: March 18, 2004Applicant: Massachusetts Institute of Technology, a Massachusetts corporationInventors: Arvind Mithal, James C. Hoe
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Patent number: 6636950Abstract: A computer architecture that includes a hierarchical memory system and one or more processors. The processors execute memory access instructions whose semantics are defined in terms of the hierarchical structure of the memory system. That is, rather than attempting to maintain the illusion that the memory system is shared by all processors such that changes made by one processor are immediately visible to other processors, the memory access instructions explicitly address access to a processor-specific memory, and data transfer between the processor-specific memory and the shared memory system. Various alternative embodiments of the memory system are compatible with these instructions. These alternative embodiments do not change the semantic meaning of a computer program which uses the memory access instructions, but allow different approaches to how and when data is actually passed from one processor to another.Type: GrantFiled: April 27, 1999Date of Patent: October 21, 2003Assignee: Massachusetts Institute of TechnologyInventors: Arvind Mithal, Xiaowei Shen, Lawrence Rogel
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Patent number: 6597664Abstract: A method for specifying and synthesizing a synchronous digital circuit by first accepting a specification of an asynchronous system in which stored values are updated according to a set of state transition rules. For instance, the state transition rules are specified as a Term Rewriting System (TRS) in which each rule specifies a number of allowable state transitions, and includes a logical precondition on the stored values and a functional specification of the stored values after a state transition in terms of the stored values prior to the state transition. The specification of the asynchronous circuit is converted into a specification of an synchronous circuit in which a number of state transitions can occur during each clock period.Type: GrantFiled: August 19, 1999Date of Patent: July 22, 2003Assignee: Massachusetts Institute of TechnologyInventors: Arvind Mithal, James C. Hoe
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Patent number: 6526481Abstract: A methodology for designing a distributed shared-memory system, which can incorporate adaptation or selection of cache protocols during operation, guarantees semantically correct processing of memory instructions by the multiple processors. A set of rules includes a first subset of “mandatory” rules and a second subset of “voluntary” rules such that correct operation of the memory system is provided by application of all of the mandatory rules and selective application of the voluntary rules. A policy for enabling voluntary rules specifies a particular coherent cache protocol. The policy can include various types of adaptation and selection of different operating modes for different addresses and at different caches. A particular coherent cache protocol can make use of a limited capacity directory in which some but not necessarily all caches that hold a particular address are identified in the directory.Type: GrantFiled: April 27, 2000Date of Patent: February 25, 2003Assignee: Massachusetts Institute of TechnologyInventors: Xiaowei Shen, Arvind Mithal, Lawrence Rogel