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

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Memory Layout inside an Application

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

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.

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.

How does memzone monitor works? 16pt Intel Clear Subhead

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

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.

How does Memzone Monitor works?

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

How does Memzone Monitor works?

Troubleshooting – DPDK Memzone Dump

Troubleshooting – DPDK Memzone Dump

Backup – address sanitizer working (canary)