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diff --git a/src/plugins/mdata/mdata_doc.md b/src/plugins/mdata/mdata_doc.md deleted file mode 100644 index cbbfb012183..00000000000 --- a/src/plugins/mdata/mdata_doc.md +++ /dev/null @@ -1,24 +0,0 @@ -# Buffer metadata change tracker {#mdata_doc} - -## Introduction - -The mdata plugin uses the vlib main loop "before" performance counter -hook to snapshoot buffer metadata before calling the node dispatch -function. Similarly, the plugin uses the main loop "after" hook to -compare a vectors' worth of buffer metadata after the fact. - -The comparison function is a simple octet-by-octet A != B check. We -accumulate changed octets per-node across the entire run, using a -single spinlock-protected accumulator. - -The "show buffer metadata" command produces a report of all fields -whose values are changed by nodes visited during a given run. - -Since many fields in the vnet_buffer_opaque_t are union members, -it may appear that a certain node changes numerous fields. The entire -point of the exercise is to warn developers that if a packet visits -node N, data placed into opaque union field F *will* be affected. - -One should never assume much about buffer metadata immutability across -arbitrary subgraphs. This tool generates accurate reports, to the -extent that one exercises the required subgraph trajectories. |