As stated by Frederik,

If you want to launch more than 20 tsp provider on the same
host you'll have to

1) edit tsp/src/core/include/tsp_const_def.h
   setup you wanted value, e.g.
   #define TSP_MAX_SERVER_NUMBER 50

2) recompile + install TSP on your target platforms
   see §2.3 of "TSP Programming Tutorial"
   see Download section
     --> documentations/tsp_programming_tutorial-1.0.pdf

3) Recompile your consumers and provider in order
   to take into account the new value.

the TSP_MAX_SERVER_NUMBER is used to size some static arrays
in TSP core we could theoretically get rid of it using
dynamic allocation, but it never seems to be necessary....
until now.

No, if I remember correctly, it is used to allocate some arrays at compile time. You should be able to run way more servers than that, provided your machine is big enough.

Regards,
Frederik