Frequently Asked Questions

GEMINI

1. Why Gemini?

At NetSpeed, we speak 4 languages: Flexibility, Scalability, Deadlock-free and Physical-awareness in a coherent fashion.  We strongly feel, and many customers agreed, that system architect should have the freedom to build any cache hierarchy as they think the best for the application.  Gemini does exactly that.   By giving customer a fully distributed cache hierarchy solution, Gemini unleashes the physical design constraints and allows SOC blocks to be placed anywhere on the die while still meeting timing at ease with NetSpeed physical-aware synthesis / design capture platform – NocStudio.

2. Who can use Gemini?

Any existing AMBA based SOC with coherency can benefit from Gemini's full configurability.  Instead of having a semi-fixed coherency block, Gemini offers 3 flexibly placable components: CCC - Directory based Cache Coherency Controller IP, IOCB - IO Coherent Bridge / Accelerator and DVM - Distributed Virtual Memory.  Each component can be instantiated as many times as needed and can be placed at any desirable location.  NocStudio synthesis engine can then construct the NoC with Gemini to satsify the requirements cohrently and non-coherently, functionally and physically.

3. What protocol can Gemini support?

As Gemini is a superset of Orion – NetSpeed non-coherent solution, in addition to the standard non-coherrent AMBA protocols: AXI4, AXI3, AHB, APB, etc., Gemini supports ACE, ACE-Lite and ACE-Lite w/ DVM.  Gemini is the industry first single solution to esnure a deadlock free NoC for the entire system.

4. Why do I need multiple CCC in my SOC?

For starters, a single CCC who can manages all coherency traffic is probably good enough.  As complexity increases in modern SOCs, having multiple CCCs can increase the overall coherent bandwidth.  Secondly, distributed directory means smaller directory RAM size for each CCC, therefore it will reduce overall system latency due to faster memory access time.   Lastly multiple CCCs provides placement flexibility where each CCC can be placed as close as possible to their connecting coherent masters, respectively.

5. Why buy Gemini?
  • Innovate: Unlike other fixed-point solutions, Gemini offers unlimited configurability. This allows architects to design the interconnect to fit their needs instead of designing the system to fit the interconnect.
  • Simplify: Gemini takes the pain out of building coherent systems. We are deadlock-free both at protocol and network level. We offer an integrated performance simulator to test your ideas in minutes, not months.
  • Excel: Gemini beats our competition's performance numbers... by a lot. The combination of NocStudio and our innovation in the coherency IP (CCC, IOCB, Directory) offers much better latency than our competitors.

GEMINI

1. What kind of address mapping supported between master ports, address range, address interleave, load balance, or others?

Slaves or targets may have one or more address ranges. A master device may access all or a subset of these address ranges. Furthermore, though a slave address range may be accessible to a master device, it may be disabled, or selectively enabled for reads or writes, or for accesses with secure privilege. The initial register map and access privileges can be set up through NocStudio, but it may be modified in silicon through Regbus programming. Address mapping could be highly interleaving with different granularities.

2. Does Gemini support speculative read?

Yes, Gemini supports speculative read.

3. Is there any dummy snooping after being filtered?

No, Gemini does not need to do any dummy snooping. We have a directory based solution that filters unncessary snoops.

4. Does Gemini support partial clock gating or shutdown?

Yes, we support partial clock gating under system firmware control or NoC adaptive control.

5. Does Gemini have transaction splitter for I/O coherent masters?

Yes. Gemini supports transaction splitter for I/O coherent masters.

6. How does Gemini support WriteUnique transactions?

Yes. Gemini supports WriteUnique in order.

7. How does Gemini support exclusive transactions?

Gemini provides transportation for non-coherent exclusive transactions. It also supports coherent exclusive transactions with tracking address per agent.

8. How does Gemini support barrier transactions?

For IO coherent transactions, Gemini propagates them through the network whereas for others it waits for the prior transactions to complete.

9. Is it supported to route coherent and non-coherent accesses to different master ports?

Yes, Gemini can route coherent and non-coherent accesses to different master ports.

10. Could the snoop to ACE slave ports be disabled dynamically?

Yes, slave ports could be disabled dynamically.

11. What kind of QoS algorithm is supported in Gemini?

NetSpeed Gemini supports multiple QoS mechanisms: traffic isolation, strict priority-based and weighted allocations. Additionally, NoC virtual channels are algorithmically optimized to best fit floorplan, connectivity and to reduce power.

12. Does Gemini provide performance monitors?

NetSpeed Gemini supports multiple performance registers in the NoC. These performance registers are programmable and can be used to measure bandwidth, latency and other notable events at runtime. These performance registers are accessible through a separate physical layer called the “RegBus”.

GEMINI

1. Can we get the bandwidth or latency number after reading any performance register?

Yes, NetSpeed Gemini supports multiple performance registers in the NoC. These performance registers are programmable and can be used to measure bandwidth, latency and other notable events at runtime. These performance registers are accessible through a separate physical layer called the “RegBus”.

2. How do we debug the bus behavior?

We provide a comprehensive set of debug mechanism to enable pre-silicon and post-silicon verification and debugging. Some of the capabilities/features include:

  • Detailed NoC routing information
  • RTL simulation-based checkers and monitors
  • Automated debugging tools
  • Quick dependency & deadlock analysis

GEMINI

1. Can it support asynchronous clock domain crossing? Can it support synchronous clock domain crossing (clock ratio from 1:N to N:1)?

Yes, we support both async as well as a 1:N and N:1 clock domain crossing.

2. What kind of dynamic clock gating does Gemini support?

External system level clock gating, adaptive coarse grained clock gating (which automatically gates inactive blocks) and fine grained clock gating.

3. Does Gemini support partial clock gating or shutdown?

Yes, we support partial clock gating under system firmware control or NoC adaptive control.

GEMINI

1. If we need to divide NoC to many voltage domains, do you have any asynchronous voltage domain crossing bridge?

Yes, we will allow insertion of async FIFOs in our router than will enable asynchronous voltage domain crossing bridge as well.

2. If we need to divide NoC to many power domains, can we divide the bus anywhere?

Yes, the NoC can be divided across power domain boundaries. On top of this, Gemini provides a comprehensive Low Power solution.  It optimizes power-domain allocation based on SoC level power profiles and power mixes. A demo of NocStudio will be able to demonstrate our sophisticated low-power approach. Please contact us for more details.

GEMINI

1. Could it support ARM's Trust Zone feature?

Gemini supports ARM Trust Zone controller which gates the memory. In addition, Gemini also provides fine-grained features of secure memory access. With address ranges specified for slave bridges, master bridges could be set up to have restricted access to specific slave address ranges. For Coherent Cache, the “secure/non-secure” protection bit of AXI channels are also used, in conjunction with the cache directories, to ensure secure cache access.

Request A Demo

ajaxloader

Crafted @ Lollypop.biz