1. By Vipin Varghese Application Engineer (NCSD)
Memory Zone Monitor By
Vipin Varghese
Application Engineer (NCSD)

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3. Memory Layout inside an Application

4. Quote with Attribute
“What happens inside an Application, does not stay within the application.”
12pt Intel Clear for Quote Name if Needed

5. Why?
DPDK application makes uses of huge page areas to store lookup table, counters, results and information used in Data plane and Control plane instances.
As memory layout is shared across multiple process, this can lead to
Unintended changes within the same process
Unintended changes from multi process
Application logic or function pointers modifying unintended areas
Above cases leads to undefined and erratic program behaviour.
Debugging the right entry is difficult.

6. Where?
Application can make use of MEMZONE regions for storing data for various purposes.
Table are not limited to
Lookup only
Lookup + Result
Lookup + Result + Counters
Counters or Index to Counters
Reference to Lookup, Lookup + Result and Lookup + Result + Counter,
The deployed applications in field are stripped, build with static or dynamic libraries, GDB or remote GDB to target is absent.

7. How does memzone monitor works?
16pt Intel Clear Subhead

8. Generic Application
User can design his tables to be held completely under memzone or reference.
Holding entries completely in memzone
Saves memory from being allocated.
All elements are placed in same region.
Holding references to entries
No need to pre allocate huge memory regions from start.
Memory can grow and shrink as required.
Easier add/delete with Optimization in lookup

9. How does it monitor?
Works as secondary application, which periodically monitor selected tables or memory region. Reports back the offset where the change has occurred.
Helps to
Isolate the table or counter where the change is occurring
Reports the offset (RTE_CACHELINE) from the address
Can monitor multiple tables.

10. How does Memzone Monitor works?

11. Is memzone monitor the solution?
No, it is just an utility to identify where the cause of irregular behaviour can be happening.

14. How does Memzone Monitor works?

16. Troubleshooting – DPDK Memzone Dump

17. Troubleshooting – DPDK Memzone Dump

18. Backup – address sanitizer working (canary)