Microsoft Technology Licensing, LLC

Workman Nydegger

Juan Carlos Arevalo Baeza

Jordi Mola

William Chen

Barry Friemel

Daniel Dinu

Patrick Nelson

Thomas Lai

Del Myers

Jackson Michael Davis

Darek Josip Mihocka

Deborah Chen

Yongjun Wu

Weidong Zhao

Andrew R Sterland

Jason Matthew Gould

Kenneth W Sykes

Sean M Callahan

Eric Christoffersen

James M Pinkerton

Leslie Yvette Richardson

Michael Burrows

Stephen Harris Toub

David Floyd Aronson

Matthew William Lee

John H Palevich

Parham Mohadjer

Yegnaswamy Sermadevi

Matthew Russell Kimball

Karen Elaine Stevens

Ivette Carreras

Andrew Goossen

Darek Josip Michocka

Video decoding innovations for multithreading implementations and graphics processor unit ('GPU') implementations are described. For example, for multithreaded decoding, a decoder uses innovations in the areas of layered data structures, picture extent discovery, a picture command queue, and/or task scheduling for multithreading. Or, for a GPU implementation, a decoder uses innovations in the areas of inverse transforms, inverse quantization, fractional interpolation, intra prediction using waves, loop filtering using waves, memory usage and/or performance-adaptive loop filtering. Innovations are also described in the areas of error handling and recovery, determination of neighbor availability for operations such as context modeling and intra prediction, CABAC decoding, computation of collocated information for direct mode macroblocks in B slices, reduction of memory consumption, implementation of trick play modes, and picture dropping for quality adjustment.

Video decoding implementations for a graphics processing unit

Based on replay of a thread, one implementation observes an influx of a value of a memory cell comprising an interaction between the thread and the value of the memory cell at an execution time point in the replaying, and determines whether the value of the memory cell observed from the influx is inconsistent with a prior value of the memory cell as known by the thread at the execution time point. If so, this implementation initiates an indication of a data inconsistency. Based on replay of a plurality of threads, another implementation identifies a memory cell that was accessed by a first thread while a thread synchronization mechanism was active on the first thread. Then, if there was another access to the memory cell by a second thread without use of the thread synchronization mechanism, this implementation initiates an indication of a potential data contention.

Identifying data inconsistencies and data contention based on historic debugging traces

Expressly turning tracing on and off at each juncture between code that a developer wants to have traced and other code may reduce trace file size but adds computational cost. Described technologies support selectively tracing a process's execution, with some extra tracing done beyond the code the developer wanted traced, but with significantly reduced computational cost, by reducing the number of trace enablement and disablement operations. A trace controller uses a tracing disablement distance variable whose values indicate the computational distance from trace disablement. A distance variable modifier automatically moves the distance variable closer to a stop-tracing value as the process executes. The amount of extra tracing is balanced against the reduction in trace enablement/disablement operations by tuning thresholds, based on information about routine size and computational cost. Operation of the trace controller is illustrated by sample APIs, a tracing state diagram, and a side-by-side comparison, among other items.

Selectively tracing portions of computer process execution

Identifying and reporting potential data inconsistencies and/or potential data contentions based on historic debugging traces. Based on replay of a thread, some implementations observe an influx of a value to a memory cell, and determine whether the value of the memory cell observed from the influx is inconsistent with a prior value of the memory cell as known by the thread. If so, these implementations can initiate an indication of a data inconsistency. Based on replay of a plurality of threads, other implementations identify a memory cell that was accessed by a first thread while a thread synchronization mechanism was active on the first thread. Then, if there was another access to the memory cell by a second thread without use of the thread synchronization mechanism, these implementations might initiate an indication of a potential data contention.

Querying resource lifetime using a trace of program execution. An embodiment includes identifying a query expression targeted at least a portion of the trace of program execution. The query expression specifies at least (i) a data object representing a plurality of events identified in the trace, each event associated with one or more attributes relating to resource lifetime, and (ii) one or more conditions matching the one attributes relating to resource lifetime. In response to receiving the query expression, the query expression is processed based at least on an analysis of an identified subset of the trace. Based on processing the query expression, a result data set that includes or identifies at least one of the plurality of events that meets the one or more conditions is presented.

Indexing time-travel traces

Described technologies support selectively tracing a process's execution, with some extra tracing done beyond the code the developer wanted traced, but with significantly reduced computational cost, by reducing the number of trace enablement and disablement operations. A trace controller uses a tracing disablement distance variable whose values indicate the computational distance from trace disablement. A distance variable modifier automatically moves the distance variable closer to a stop-tracing value as the process executes. A create task function is modified to include the setting of an indicator that a newly created task is to be traced if a current task or thread is being traced. An execute task function is modified to request the tracing of the newly created task when it is executed based on the indicator, thereby enabling selective tracing that operates across process boundaries and traces asynchronous code execution.

Described technologies extend the information available from an execution trace of a program by providing heuristically-derived values for memory contents when the trace does not include data expressly showing the value of a memory cell at a particular execution time. Various heuristics are described. The heuristics may use information about the memory cell at other times to produce the derived value. Some heuristics use other trace data, such as whether the memory cell is in a stack, whether there are gaps in the trace, or whether garbage collection or compilation occurred near the time in question. Grounds for the derived value are reported along with the derived value. A time-travel debugger or other program analysis tool can then present the derived values to users, or make other use of the derived values and grounds to assist debugging and other efforts to improve the functioning of a computing system.

Level-crossing memory trace inspection queries

Techniques for processing recorded program data are described. In implementations, a trace module in a computing device processes instructions of a recorded program and generates a trace file for program optimization. In implementations, the trace module records a subset of a received program for inclusion in the trace file. The computing device can also or instead be implemented to gather and initiate analysis of application data proactively and without user initiation.

Partial process recording

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Bellevue, WA, United States of America

Juan Carlos Arevalo Baeza