Posted by VIP Experts on December 19, 2017
Is your latest NVMe design taking advantage of Streams? Adoption of this new NVMe technology is gaining momentum with Synopsys customers. Streams are part of the new, optional, Directives feature introduced in the NVMe 1.3 specification. Directives allow the passing of metadata between hosts and controllers via existing NVMe commands. Streams are unique in that they are the only I/O based Directive available in the 1.3 specification.
So, what are Streams? Streams piggyback onto the write command’s header and allow for multiple logical blocks to be associated as one group of data. Associations may include being part of a single process or being tagged to one of many virtual machines in a system. The controller uses the identification of the Stream to guide the storage or garbage collection of data. Stream can also be used to target specific optimizations for the controller.
A common use is the allocation and deallocation/garbage collection of data blocks. Associating the logical blocks as one Stream allows it to be allocated, written, and deleted at a block level improving performance and reducing NAND block fragmentation.
SSD without support for Stream Directive
SSD with support for Stream Directive
Streams are an exciting addition to the NVMe specification. By improving allocation of LBAs, the SSD’s Flash memory endurance and performance can be improved. While much of the Stream interpretation is left to the Controller design team, it’s important to have a verification solution that easily enables you to allocate streams and initiate traffic with multiple Stream IDs for each supported namespace. The Synopsys VC VIP for NVMe provides full control of host generated Streams along with an extensive Test Suite to accelerate the verification of your NVMe 1.3 based design.
In-order to educate the design and verification community, Synopsys presented an NVMe webinar. The webinar provides an overview of the NVMe standard and its use as a storage solution. In addition, it highlights how Synopsys’ VIP for NVMe enables designers to keep pace with the ever-evolving storage landscape. We have complimented the webinar with a series of posts on NVMe VIP. Our VIP experts have provided insight on Synopsys NVMe VIP starting from a high level view, describing verification features and host protocol layers, and continuing with a test case walkthrough.
For more information on Synopsys NVMe and other VIP, please visit: https://www.synopsys.com/vip.
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