Nvidia Corporation

Ram Rangan

Wishwesh Anil Gandhi

Praveen Krishnamurthy

Suryakant Patidar

Emmett Michael Kilgariff

Patrick Richard Brown

Steven James Heinrich

Mark William Stephenson

Daniel Robert Johnson

Rishkul Kulkarni

Sana Damani

Dong Han Ryu

Marc Blackstein

Mathias Heyer

Warp sharding techniques to switch execution between divergent shards on instructions that trigger a long stall, thereby interleaving execution between diverged threads within a warp instead of across warps. The technique may be applied to mitigate pipeline stalls in applications with low warp occupancy and high divergence. Warp data cache locality may also be improved by concentrating memory accesses within a warp rather than spreading them across warps.

Techniques for divergent thread group execution scheduling

Accesses between a processor and its external memory is reduced when the processor internally maintains a compressed version of values stored in the external memory. The processor can then refer to the compressed version rather than access the external memory. One compression technique involves maintaining a dictionary on the processor mapping portions of a memory to values. When all of the values of a portion of memory are uniform (e.g., the same), the value is stored in the dictionary for that portion of memory. Thereafter, when the processor needs to access that portion of memory, the value is retrieved from the dictionary rather than from external memory. Techniques are disclosed herein to extend, for example, the capabilities of such dictionary-based compression so that the amount of accesses between the processor and its external memory are further reduced.

Techniques for dynamically compressing memory regions having a uniform value

Some systems compress data utilized by a user mode software without the user mode software being aware of any compression taking place. To maintain that illusion, such systems prevent user mode software from being aware of and/or accessing the underlying compressed states of the data. While such an approach protects proprietary compression techniques used in such systems from being deciphered, such restrictions limit the ability of user mode software to use the underlying compressed forms of the data in new ways. Disclosed herein are various techniques for allowing user-mode software to access the underlying compressed states of data either directly or indirectly. Such techniques can be used, for example, to allow various user-mode software on a single system or on multiple systems to exchange data in the underlying compression format of the system(s) even when the user mode software is unable to decipher the compression format.

Techniques for accessing and utilizing compressed data and its state information

Techniques for scaling dictionary-based compression

Profile-guided optimization is a technique for optimizing execution of computer programs using profile information to improve program runtime performance. Obtaining the profile information can be challenging, especially in live production environments such as high-performance gaming systems. A profiling strategy is provided herein that obtains profile information without requiring extra effort from users. The profiling strategy collects several approximate, lightweight profiles called piecemeal profiles over one or more lifetimes of a computer program, or application. The piecemeal profiles are then used to generate whole program application profiles that can then be used to improve the execution of the application. A piecemeal profile is profile information of a section or portion of an application.

Optimizing execution of computer programs using piecemeal profiles

A technique selectively avoids memory fetches for partially uniform textures in real time graphics shader programs and instead uses program paths specialized for one or more frequently occurring values. One aspect avoids memory lookups and dependent computations for partially uniform textures through use of pre-constructed coarse-grained representations called value locality maps or dirty tilemaps (DTMs). The decision to use a specialized fast path or not is made dynamically by consulting such coarse-grained dirty tilemap representations. Thread-sharing value reuse can be implemented with or instead of the DTM mechanism.

Techniques for efficiently accessing memory and avoiding unnecessary computations

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Tamil Nadu, India

Ram Rangan