BufferProvider: draft a test setup to play through usage scenarios

The goal is to develop a heuristic when to trigger clean-up of the local pool.

For developing this heuristic, I'll use a unit-test
- represent "allocations" by dummy buffer pointers
- use a queue and a stack to push those "allocations" around
- the "global pool" is just a queue with such dummy pointers
- next step is to define some λ-primitives
- finally, a λ-DSL to allow to perform "N operations of kind X"

src/vault/mem/local-mem-pool.hpp

@@ -407,13 +407,13 @@ namespace mem   {
           ENSURE (this->empty());
         }
       
-    private:
       void
       ingest()
         {
           inQueue_.consume_all ([this](Alloc alloc){ supplyImmediately (move(alloc)); });
         }
       
+    private:
       template<class PRED>
       Block const*
       findMatch (PRED&& predicate)  const

tests/vault/mem/local-mem-pool-test.cpp

@@ -19,11 +19,16 @@
 #include "test/run.hpp"
 #include "test/test-helper.hpp"
 #include "vault/mem/local-mem-pool.hpp"
+#include "lib/iter-explorer.hpp"
 #include "lib/iter-stack.hpp"
 #include "lib/format-util.hpp"
+#include "test/diagnostic-output.hpp"////////////TODO
 
+#include <concepts>
 
 using util::join;
+using lib::explore;
+using std::invocable;
 
 namespace vault {
 namespace mem   {
@@ -302,6 +307,7 @@ namespace test  {
       
       
       /** @test heuristic trigger mechanism for pool clean-up
+       *      - use a setup where the global pool is just a queue of buffer pointers
        *      - create abbreviated notation to play through various scenarios
        *      - watch how turnover and max-score are computed for each step
        *      - document the trigger points for heuristic clean-up.
@@ -309,7 +315,101 @@ namespace test  {
       void
       verify_turnoverTrigger()
         {
+          LocalMemPool pool;
+          lib::IterQueue<Buff*> globalPool;
+          lib::IterStack<Buff*> usedBuff;
+          size_t SIZ = SIZ10;
           
+          //------------ pretty printing of "allocations"
+          auto buffID  = [](Buff* buff){ return size_t(buff); };
+          auto show    = [&](auto coll){ return join (explore(coll).transform(buffID)); };
+          
+          
+          //------------ define abstracted form of the basic actions on the pool...
+          
+          auto pullMem = [&]{ // retrieve one allocation from global pool
+                              if (globalPool)
+                                {
+                                  pool.supply (*globalPool, SIZ);
+                                  pool.ingest();
+                                  ++globalPool;
+                                }
+                            };
+          
+          auto pushMem = [&](Buff* mem, size_t)
+                            { // return one allocation into global pool
+                              globalPool.feed (mem);
+                            };
+          
+          auto useMem  = [&]{ // claim one allocation from local pool
+                              auto [mem,_] = pool.retrieve (SIZ);
+                              usedBuff.push(mem);
+                            };
+          
+          auto freeMem = [&]{ // return one used allocation into local pool
+                              if (usedBuff)
+                                {
+                                  pool.reSupply (*usedBuff);
+                                  ++usedBuff;
+                                }
+                            };
+          
+          auto repeat  = [](uint n, invocable<> auto action)
+                            {
+                              for (uint i=0; i<n; ++i)
+                                action();
+                            };
+          
+          
+          //------------ define four building blocks for scenarios
+          
+          auto reserve = [&](uint n){ pool.reserve(n, SIZ); };
+          auto supply  = [&](uint n){ repeat(n, pullMem);   };
+          auto claim   = [&](uint n){ repeat(n, useMem );   };
+          auto free    = [&](uint n){ repeat(n, freeMem);   };
+          
+          // populate the global pool with some "allocations"
+          globalPool.feed(MEM11)
+                    .feed(MEM12)
+                    .feed(MEM13)
+                    .feed(MEM21)
+                    .feed(MEM31)
+                    .feed(MEM32)
+                    .feed(MEM33);
+          
+SHOW_EXPR(show(globalPool));
+SHOW_EXPR(watch(pool).size())
+          
+          supply(3);
+          
+SHOW_EXPR(show(globalPool));
+SHOW_EXPR(watch(pool).size())
+SHOW_EXPR(watch(pool).cntFree())
+          
+          reserve(2);
+          
+SHOW_EXPR(watch(pool).size())
+SHOW_EXPR(watch(pool).cntFree())
+SHOW_EXPR(watch(pool).cntResd())
+          
+          claim(3);
+          
+SHOW_EXPR(watch(pool).size())
+SHOW_EXPR(watch(pool).cntFree())
+SHOW_EXPR(watch(pool).cntResd())
+SHOW_EXPR(show(usedBuff));
+          
+          free(3);
+          
+SHOW_EXPR(watch(pool).size())
+SHOW_EXPR(watch(pool).cntFree())
+SHOW_EXPR(watch(pool).cntResd())
+SHOW_EXPR(show(usedBuff));
+          
+          pool.yield (3, SIZ, pushMem);
+          
+SHOW_EXPR(watch(pool).size())
+SHOW_EXPR(show(globalPool));
         }
       
     };

wiki/thinkPad.ichthyo.mm

@@ -146986,7 +146986,28 @@ StM_bind(Builder<R1> b1, Extension<R1,R2> extension)
 <node CREATED="1778979230293" ID="ID_1129342480" MODIFIED="1779664866045" TEXT="meine Idee der Heuristik umsetzen">
 <arrowlink COLOR="#4d5f6c" DESTINATION="ID_1141255727" ENDARROW="Default" ENDINCLINATION="-376;22;" ID="Arrow_ID_514664149" STARTARROW="None" STARTINCLINATION="-76;-210;"/>
 </node>
-<node CREATED="1778979241959" ID="ID_241540634" MODIFIED="1778979251687" TEXT="mit einzelnen Grenz-Szenarien durchspielen"/>
+<node CREATED="1778979241959" ID="ID_241540634" MODIFIED="1778979251687" TEXT="mit einzelnen Grenz-Szenarien durchspielen">
+<node COLOR="#338800" CREATED="1779670307076" ID="ID_850518169" MODIFIED="1779677812089" TEXT="brauche daf&#xfc;r ein &#xbb;Baukastensystem&#xab; f&#xfc;r Szenarien">
+<icon BUILTIN="yes"/>
+<node BACKGROUND_COLOR="#c8c0b6" COLOR="#435e98" CREATED="1779670329822" ID="ID_1971093649" MODIFIED="1779677820109" TEXT="Idee: eine &#x3bb;-DSL">
+<icon BUILTIN="idea"/>
+</node>
+<node COLOR="#435e98" CREATED="1779670579244" ID="ID_1221276556" MODIFIED="1779677834308" TEXT="Primitive">
+<font BOLD="true" NAME="SansSerif" SIZE="12"/>
+<icon BUILTIN="list"/>
+<node CREATED="1779670594268" ID="ID_1451616229" MODIFIED="1779670611189" TEXT="eine kontexturell vorgegebene SIZE"/>
+<node CREATED="1779677581012" ID="ID_1406506279" MODIFIED="1779677594870" TEXT="einen kontextuellen &#xbb;globalen Pool&#xab;"/>
+<node CREATED="1779670699998" ID="ID_954266367" MODIFIED="1779670719943" TEXT="einen kontextuellen Stack mit belegten Allocs"/>
+<node CREATED="1779670614712" ID="ID_603310345" MODIFIED="1779670676968" TEXT="reserve(N)"/>
+<node CREATED="1779670677760" ID="ID_1175480047" MODIFIED="1779670681979" TEXT="supply(N)"/>
+<node CREATED="1779670733857" ID="ID_1430519739" MODIFIED="1779670739180" TEXT="claim(N)"/>
+<node CREATED="1779670739992" ID="ID_1222609344" MODIFIED="1779670767260" TEXT="free(N)"/>
+</node>
+<node COLOR="#338800" CREATED="1779677790937" ID="ID_60505507" MODIFIED="1779677803941" TEXT="einfachen Fall mit pretty-Printing durchspielen...">
+<icon BUILTIN="button_ok"/>
+</node>
+</node>
+</node>
 <node CREATED="1778979252922" ID="ID_155080806" MODIFIED="1778979264429" TEXT="Verhalten sollte deterministisch vorhersagbar sein"/>
 </node>
 </node>