lumiera_documentation/tests/vault/mem/local-buffer-store-test.cpp
Ichthyostega 7989e825b9 BufferProvider: integrate and verify heuristic trigger of clean-up
The mechanism is tuned now to engage rather quickly
whenever excess capacity builds up in a local allocator pool,
but when all buffers are used most of the time, they will be retained.

Can now demonstrate by integration test that capacity is sent back.
2026-05-26 04:39:41 +02:00

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/*
LocalBufferStore(Test) - verify thread-local buffer memory allocator proxy
Copyright (C)
2026, Hermann Vosseler <Ichthyostega@web.de>
  **Lumiera** is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version. See the file COPYING for further details.
* *****************************************************************/
/** @file local-buffer-store-test.cpp
** unit test \ref LocalBufferStore_test
*/
#include "test/run.hpp"
#include "test/test-helper.hpp"
#include "vault/mem/local-buffer-store.hpp"
#include "vault/mem/engine-buffer-manager.hpp"
#include "vault/mem/engine-buffer-allocator.hpp"
#include "lib/depend-inject.hpp"
#include "lib/thread.hpp"
#include "lib/util.hpp"
#include <algorithm>
#include <atomic>
using util::isSameAdr;
using lib::Thread;
using std::this_thread::yield;
using std::this_thread::sleep_for;
using std::chrono_literals::operator ""ms;
namespace vault {
namespace mem {
namespace test {
/*********************************************//**
* @test verify memory handling in worker
* that relies on a thread-local allocation pool.
*/
class LocalBufferStore_test : public Test
{
virtual void
run (Arg)
{
verify_API();
verify_announce();
verify_allocate();
verify_release();
}
/** @test demonstrate a typical usage cycle of the BufferStore in concurrent setup
* - the main thread provides a mock instance of the EngineBufferManager
* - furthermore, the LocalBufferStore instance is created here
* - yet note: LocalBufferStore includes a LocalMemPool per thread
* - a test thread is launched to issue some allocation requests
* - announce some memory allocation demand
* - claim and use one buffer
* - generate further demand to trigger further allocation supply
* - terminate the thread
* - verify the number of allocations seen in the EngineBufferManager
*/
void
verify_API()
{
// provide a »central BufferPool« (as a transient instance for this test)
lib::DependInject<EngineBufferManager>::Local<EngineBufferManager> globalPool;
// provide the *test subject*,
// which implements the BufferStore API
// and uses a thread-local allocation pool internally
LocalBufferStore localStore;
BufferProviderSetup::Store& storeAPI = localStore;
const size_t BUFFSIZ = 555;
const HashVal TYPEID = 12345;
const size_t CNT = 5;
const int64_t ARG = 7;
const LocalTag MARK{42};
const size_t ALLOC = HeapBufferAllocator::numTiles(BUFFSIZ) * HeapBufferAllocator::TILE_SIZ;
Thread testWorker{[&] /* === Play through one typical usage cycle === */
{
uint avail = storeAPI.prepareBuffers(TYPEID, CNT, BUFFSIZ);
CHECK (0 == avail);
BuffAlloc storageSlot = storeAPI.provideBuffer (TYPEID, BUFFSIZ, MARK, ARG);
auto& [storage,buffSiz,specifics] = storageSlot;
CHECK (storage);
CHECK (BUFFSIZ <= buffSiz);
CHECK (ALLOC == buffSiz);
CHECK (MARK == specifics);
// can use that memory
char* buf = reinterpret_cast<char*> (storage);
std::string ranS{lib::randStr(555-1)};
auto* p = std::copy (ranS.begin(), ranS.end(), buf);
CHECK (ranS.length() == size_t(p - buf));
*p = '\0';
CHECK (ranS == buf);
// reserve four additional buffers;
// these happen to sit already in the local pool anyway
// and will be marked as "reserved" now....
avail = storeAPI.prepareBuffers(TYPEID, 4, BUFFSIZ);
CHECK (4 == avail);
// finish usage and return the single buffer claimed thus far...
storeAPI.mark_emitted (TYPEID, storageSlot);
storeAPI.detachBuffer (TYPEID, storageSlot);
// now we have 5 buffers in the pool, but 4 are marked as "reserved"
// thus only one buffer can be confirmed and one further is requested from EngineBufferManager
avail = storeAPI.prepareBuffers(TYPEID, 2, BUFFSIZ);
CHECK (1 == avail);
// but irrespective of reservation, we can immediately use the buffers locally available
BuffAlloc slot1 = storeAPI.provideBuffer (TYPEID, BUFFSIZ, MARK, ARG);
auto& [sto1,siz1,tag1] = slot1;
BuffAlloc slot2 = storeAPI.provideBuffer (TYPEID, BUFFSIZ, MARK, ARG);
auto& [sto2,siz2,tag2] = slot2;
CHECK (sto1);
CHECK (sto2);
CHECK (isSameAdr (storage, sto1));
CHECK (not isSameAdr (storage, sto2));
CHECK (BUFFSIZ <= siz1);
CHECK (BUFFSIZ <= siz2);
storeAPI.detachBuffer (TYPEID, slot2);
storeAPI.detachBuffer (TYPEID, slot1);
}}; // LocalMemPool winds down at end of thread
while (testWorker)
yield(); // wait for worker to finish
// additional delay for the local pool's destructor
// that is invoked after the thread has finished
sleep_for(1ms);
CHECK (globalPool); // the Mock was accessed (and thus instantiated)
// before shutdown, LocalMemPool has sent back all allocations;
// these should sit now in the EngineBufferManager's input queue,
// unprocessed yet; same for the additional buffer requested later.
// EngineBufferManager only sees the first CNT allocations actually dispatched
CHECK (CNT == watch(*globalPool).numAllocs());
CHECK (CNT*ALLOC == watch(*globalPool).bytesLeased());
// process the in-queue and retrieve all allocations...
globalPool->processPendingRequests();
// everything should be cleaned-up by now...
CHECK (0 == watch(*globalPool).bytesLeased());
}
/** @test announcement of capacity demand is propagated eventually
* - test thread must proceed in lockstep to make effects observable
* - Step-1: test thread announces demand on the subject (`BufferStore` API)
* - Step-2: „someone“ processes pending requests in the EngineBufferManager
* - Step-3: test thread announces further demand that remains unprocessed
* - test thread then terminates, sends back all allocations
* - the pending request is ignored transparently
*/
void
verify_announce()
{
// »central BufferPool« (transient instance for this test)
lib::DependInject<EngineBufferManager>::Local<EngineBufferManager> globalPool;
// *test subject*
LocalBufferStore localStore;
BufferProviderSetup::Store& storeAPI = localStore;
const size_t BUFFSIZ = 1024;
const HashVal TYPEID = 12345;
// coordination of test steps
std::atomic_uint step{1};
Thread testWorker{[&] /* === Scenario: test subject announces capacity demand === */
{
// Step-1
uint avail = storeAPI.prepareBuffers(TYPEID, 1, BUFFSIZ);
CHECK (0 == avail);
CHECK (watch(localStore).isEmpty());
// wait for being serviced...
++step;
while (step < 3)
sleep_for(1ms);
// Step-3
CHECK (not watch(localStore).isEmpty());
CHECK (watch(localStore).canServe(BUFFSIZ));
CHECK (watch(localStore).cntFree() == 1);
CHECK (watch(localStore).size() == 1);
// Note: this block was supplied but the local pool does not know why,
// since reservations are only tracked on blocks already available
CHECK (watch(localStore).cntResd() == 0);
// Now, instead of using this buffer block,
// rather generate another capacity announcement...
avail = storeAPI.prepareBuffers(TYPEID, 2, BUFFSIZ);
CHECK (1 == avail);
CHECK (watch(localStore).cntResd() == 1);
CHECK (watch(localStore).cntFree() == 1);
CHECK (watch(localStore).size() == 1);
CHECK (watch(localStore).canServe(BUFFSIZ));
// Note: while a further request is "out there",
// only a single block was received up to now.
// LocalMemPool winds down automatically at end of thread
}};
/* === Main thread: observe effects in the global pool === */
// wait until the first announcement was made
while (step < 2)
sleep_for(1ms);
// Step-2
CHECK (watch(*globalPool).numAllocs() == 0);
// process the in-queue and service the allocation request...
globalPool->processPendingRequests();
CHECK (watch(*globalPool).numAllocs() == 1);
CHECK (watch(*globalPool).bytesLeased() >= BUFFSIZ);
// let the test thread proceed...
step = 3;
// wait until test thread has wound down
while (testWorker)
sleep_for(1ms);
// additional delay to be sure the destructor of the local pool has finished
sleep_for(1ms);
CHECK (watch(*globalPool).numAllocs() == 1);
globalPool->processPendingRequests();
CHECK (watch(*globalPool).bytesLeased() == 0);
}
/** @test request an allocation from the local store, without prior announcement
* - again, a coordinated test setup is necessary to watch the effects
* - Step-1: test worker triggers the allocation and retrieves it immediately
* - Step-2: allocation and the leased-out memory is visible in the global pool
* - test worker unwinds, allocations are returned
*/
void
verify_allocate()
{
// »central BufferPool« (transient instance for this test)
lib::DependInject<EngineBufferManager>::Local<EngineBufferManager> globalPool;
// *test subject*
LocalBufferStore localStore;
BufferProviderSetup::Store& storeAPI = localStore;
const size_t BUFFSIZ = 1024;
const HashVal TYPEID = 12345;
// coordination of test steps
std::atomic_uint step{1};
Thread testWorker{[&] /* === Scenario: test subject requests allocation immediately === */
{
// Step-1
CHECK (watch(localStore).isEmpty());
BuffAlloc slot1 = storeAPI.provideBuffer (TYPEID, BUFFSIZ, 0,0);
auto& [storage,buffSiz,_] = slot1;
CHECK (storage);
CHECK (BUFFSIZ <= buffSiz);
CHECK (not watch(localStore).isEmpty());
CHECK (watch(localStore).size() == 1);
CHECK (watch(localStore).cntFree() == 0);
++step;
// allocation can be re-used locally,
// without any further exchange with the global pool
storeAPI.detachBuffer (TYPEID, slot1);
CHECK (watch(localStore).canServe(BUFFSIZ));
CHECK (watch(localStore).cntFree() == 1);
CHECK (watch(localStore).size() == 1);
BuffAlloc slot2 = storeAPI.provideBuffer (TYPEID, BUFFSIZ, 0,0);
CHECK (watch(localStore).cntFree() == 0);
// the same memory address was re-used
CHECK (slot1 == slot2);
storeAPI.detachBuffer (TYPEID, slot2);
// can even reserve that memory without any round-trip to the global pool
CHECK (watch(localStore).cntFree() == 1);
CHECK (watch(localStore).cntResd() == 0);
uint avail = storeAPI.prepareBuffers(TYPEID, 1, BUFFSIZ);
CHECK (1 == avail);
CHECK (watch(localStore).cntFree() == 1);
CHECK (watch(localStore).cntResd() == 1);
CHECK (watch(localStore).size() == 1);
CHECK (watch(localStore).canServe(BUFFSIZ));
}}; // block automatically sent back after thread end
/* === Main thread: observe effects in the global pool === */
// wait until memory was claimed
while (step < 2)
sleep_for(1ms);
// Step-2
CHECK (watch(*globalPool).numAllocs() == 1);
CHECK (watch(*globalPool).bytesLeased() >= BUFFSIZ);
// wait until test thread terminates
while (testWorker)
sleep_for(1ms);
sleep_for(1ms); // additional wait for the dtor
globalPool->processPendingRequests();
CHECK (watch(*globalPool).bytesLeased() == 0);
}
/** @test heuristic clean-up after releasing several allocations
* - at first, a de-allocated block remains available in the local pool
* - after a number of usages, defined as _turnover_, clean-up is triggered
* - this test scenario requests 5 buffers, but repeatedly uses only one
* - after the third round with this usage pattern, the local pool is reduced
*/
void
verify_release()
{
// »central BufferPool« (transient instance for this test)
lib::DependInject<EngineBufferManager>::Local<EngineBufferManager> globalPool;
// *test subject*
LocalBufferStore localStore;
BufferProviderSetup::Store& storeAPI = localStore;
const size_t BUFFSIZ = 1024;
const HashVal TYPEID = 12345;
// coordination of test steps
std::atomic_uint step{1};
Thread testWorker{[&] /* === Scenario: test subject requests allocation immediately === */
{
// Step-1 : first round
uint avail = storeAPI.prepareBuffers(TYPEID, 5, BUFFSIZ);
CHECK (0 == avail);
CHECK (watch(localStore).isEmpty());
BuffAlloc slot1 = storeAPI.provideBuffer (TYPEID, BUFFSIZ, 0,0);
auto& [storage,buffSiz,_] = slot1;
CHECK (storage);
storeAPI.detachBuffer (TYPEID, slot1);
// Result: got five allocations and all are in the local pool
CHECK (watch(localStore).size() == 5);
CHECK (watch(localStore).cntFree() == 5);
++step;
// Step-2 : repeat same pattern -- again only using one of the five buffers
BuffAlloc slot2 = storeAPI.provideBuffer (TYPEID, BUFFSIZ, 0,0);
CHECK (slot2 == slot1);
CHECK (watch(localStore).size() == 5);
CHECK (watch(localStore).cntFree() == 4);
storeAPI.detachBuffer (TYPEID, slot1);
CHECK (watch(localStore).size() == 5);
CHECK (watch(localStore).cntFree() == 5);
++step;
// Step-3 : repeat for a third time
BuffAlloc slot3 = storeAPI.provideBuffer (TYPEID, BUFFSIZ, 0,0);
CHECK (slot3 == slot1);
CHECK (watch(localStore).size() == 5);
CHECK (watch(localStore).cntFree() == 4);
storeAPI.detachBuffer (TYPEID, slot1);
// this triggered a clean-up and detected the unused capacity
CHECK (watch(localStore).size() == 1);
CHECK (watch(localStore).cntFree() == 1);
++step;
// main thread will now see the partial clean-up
while (step == 4) // wait until main thread could investigate
sleep_for(1ms);
}}; // remaining buffer automatically sent back after thread end
/* === Main thread: observe effects in the global pool === */
// wait until Step-2
while (step < 2)
sleep_for(1ms);
CHECK (watch(*globalPool).numAllocs() == 5);
// re-check after Step-2
while (step <= 2)
sleep_for(1ms);
// nothing changed; local pool operates independently
CHECK (watch(*globalPool).numAllocs() == 5);
CHECK (watch(*globalPool).bytesLeased() == 5*BUFFSIZ);
// re-check after Step-3
while (step <= 3)
sleep_for(1ms);
globalPool->processPendingRequests();
CHECK (watch(*globalPool).bytesLeased() == 1*BUFFSIZ);
// Note: local pool sent back excess capacity
++step; // allow the worker to terminate after that
while (testWorker)
sleep_for(1ms);
sleep_for(1ms); // additional wait for the dtor
globalPool->processPendingRequests();
CHECK (watch(*globalPool).bytesLeased() == 0);
// all capacity properly returned into global pool
}
};
/** Register this test class... */
LAUNCHER (LocalBufferStore_test, "unit engine");
}}} // namespace vault::mem::test