LUMIERA.clone/tests/vault/gear/scheduler-load-control-test.cpp
Ichthyostega e26d251867 Scheduler: rationalise delay decision logic
...especially for the case »outgoing to sleep«

- reorganise switch-case to avoid falling through
- properly handle the tendedNext() predicate also in boundrary cases
- structure the decision logic clearer
- cover the new behaviour in test

Remark: when the queue falls empty, the scheduler now sends each
worker once into a targted re-shuffling delay, to ensure the
sleep-cycles are statistically evenly spaced
2023-10-28 05:34:56 +02:00

307 lines
13 KiB
C++

/*
SchedulerLoadControl(Test) - verify scheduler load management facility
Copyright (C) Lumiera.org
2023, Hermann Vosseler <Ichthyostega@web.de>
This program 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.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
* *****************************************************/
/** @file scheduler-load-control-test.cpp
** unit test \ref SchedulerLoadControl_test
*/
#include "lib/test/run.hpp"
#include "vault/gear/load-controller.hpp"
#include "vault/real-clock.hpp"
//#include "lib/time/timevalue.hpp"
//#include "lib/format-cout.hpp"
//#include "lib/util.hpp"
#include "lib/test/diagnostic-output.hpp"/////////////////////TODO
//#include <utility>
using test::Test;
using std::move;
//using util::isSameObject;
namespace vault{
namespace gear {
namespace test {
// using lib::time::FrameRate;
// using lib::time::Offset;
// using lib::time::Time;
using Capacity = LoadController::Capacity;
using Wiring = LoadController::Wiring;
/*************************************************************************//**
* @test verify behaviour patterns relevant for Scheduler load control.
* @see SchedulerCommutator_test
* @see SchedulerService_test
* @see SchedulerStress_test
*/
class SchedulerLoadControl_test : public Test
{
virtual void
run (Arg)
{
simpleUsage();
classifyHorizon();
tendNextActivity();
classifyCapacity();
scatteredReCheck();
walkingDeadline();
}
/** @test TODO demonstrate a simple usage scenario
* @todo WIP 10/23 🔁 define ⟶ 🔁 implement
*/
void
simpleUsage()
{
LoadController ctrl;
/////////////////////////TODO a simple usage example focusing on load diagnostics
}
/** @test verify classification of time horizon for scheduling.
* - if the next planned Activity lies beyond the SLEEP_HORIZON,
* then the current thread can be considered part of the _idle capacity_
* - in a similar way, WORK_HORIZON delineates the zone of repeated incoming
* Activities from the zone considered part of current active operation
* - Activities within the NOW_HORIZON can be awaited by yield-spinning
* - and any event from current into the past will be scheduled right away
* @todo WIP 10/23 ✔ define ⟶ ✔ implement
*/
void
classifyHorizon()
{
Time next{0,10};
Time ut{1,0};
Time t1{0,9};
Time t2{next - SLEEP_HORIZON};
Time t21{t2 + ut};
Time t3{next - WORK_HORIZON};
Time t31{t3 + ut};
Time t4{next - NEAR_HORIZON};
CHECK (Capacity::IDLEWAIT == LoadController::classifyTimeHorizon (Offset{next - ut }));
CHECK (Capacity::IDLEWAIT == LoadController::classifyTimeHorizon (Offset{next - t1 }));
CHECK (Capacity::WORKTIME == LoadController::classifyTimeHorizon (Offset{next - t2 }));
CHECK (Capacity::WORKTIME == LoadController::classifyTimeHorizon (Offset{next - t21}));
CHECK (Capacity::NEARTIME == LoadController::classifyTimeHorizon (Offset{next - t3 }));
CHECK (Capacity::NEARTIME == LoadController::classifyTimeHorizon (Offset{next - t31}));
CHECK (Capacity::SPINTIME == LoadController::classifyTimeHorizon (Offset{next - t4 }));
CHECK (Capacity::DISPATCH == LoadController::classifyTimeHorizon (Offset::ZERO ));
CHECK (Capacity::DISPATCH == LoadController::classifyTimeHorizon (Offset{t4 - next }));
}
/** @test verify the mark for _tended next head_ Activity.
* @todo WIP 10/23 ✔ define ⟶ ✔ implement
*/
void
tendNextActivity()
{
LoadController lctrl;
Time t1{1,0};
Time t2{2,0};
Time t3{3,0};
CHECK (not lctrl.tendedNext (t2));
lctrl.tendNext (t2);
CHECK ( lctrl.tendedNext (t2));
CHECK (not lctrl.tendedNext (t3));
lctrl.tendNext (t3);
CHECK ( lctrl.tendedNext (t3));
// However — this is not a history memory...
CHECK (not lctrl.tendedNext (t1));
CHECK (not lctrl.tendedNext (t2));
CHECK ( lctrl.tendedNext (t3));
lctrl.tendNext (t1);
CHECK ( lctrl.tendedNext (t1));
CHECK (not lctrl.tendedNext (t2));
CHECK (not lctrl.tendedNext (t3));
lctrl.tendNext (t2);
CHECK (not lctrl.tendedNext (t1));
CHECK ( lctrl.tendedNext (t2));
CHECK (not lctrl.tendedNext (t3));
}
/** @test verify allocation decision for free capacity
* - due and overdue Activities are prioritised
* - keep spinning when next Activity to schedule is very close
* - otherwise, priority is to tend for the next known Activity
* - beyond that, free capacity is redistributed according to horizon
* - for incoming free capacity there is a preference to keep it sleeping,
* to allow for disposing of excess capacity after extended sleep time
* @todo WIP 10/23 ✔ define ⟶ ✔ implement
*/
void
classifyCapacity()
{
LoadController lctrl;
Time next{0,10};
Time ut{1,0};
Time t1{0,9};
Time t2{next - SLEEP_HORIZON};
Time t3{next - WORK_HORIZON};
Time t4{next - NEAR_HORIZON};
Time t5{next + ut}; // ╭────────────── next Activity at scheduler head
// │ ╭──────── current time of evaluation
// Time `next` has not been tended yet... // ▼ ▼
CHECK (Capacity::TENDNEXT == lctrl.markOutgoingCapacity (next, ut ));
// but after marking `next` as tended, capacity can be directed elsewhere
lctrl.tendNext (next);
CHECK (Capacity::WORKTIME == lctrl.markOutgoingCapacity (next, ut ));
CHECK (Capacity::WORKTIME == lctrl.markOutgoingCapacity (next, t1 ));
CHECK (Capacity::WORKTIME == lctrl.markOutgoingCapacity (next, t2 ));
CHECK (Capacity::NEARTIME == lctrl.markOutgoingCapacity (next, t3 ));
CHECK (Capacity::SPINTIME == lctrl.markOutgoingCapacity (next, t4 ));
CHECK (Capacity::DISPATCH == lctrl.markOutgoingCapacity (next,next));
CHECK (Capacity::DISPATCH == lctrl.markOutgoingCapacity (next, t5 ));
CHECK (Capacity::IDLEWAIT == lctrl.markIncomingCapacity (next, ut ));
CHECK (Capacity::IDLEWAIT == lctrl.markIncomingCapacity (next, t1 ));
CHECK (Capacity::IDLEWAIT == lctrl.markIncomingCapacity (next, t2 ));
CHECK (Capacity::NEARTIME == lctrl.markIncomingCapacity (next, t3 ));
CHECK (Capacity::SPINTIME == lctrl.markIncomingCapacity (next, t4 ));
CHECK (Capacity::DISPATCH == lctrl.markIncomingCapacity (next,next));
CHECK (Capacity::DISPATCH == lctrl.markIncomingCapacity (next, t5 ));
// tend-next works in limited ways also on incoming capacity
lctrl.tendNext (Time::NEVER);
CHECK (Capacity::IDLEWAIT == lctrl.markIncomingCapacity (next, ut ));
CHECK (Capacity::IDLEWAIT == lctrl.markIncomingCapacity (next, t1 ));
CHECK (Capacity::IDLEWAIT == lctrl.markIncomingCapacity (next, t2 ));
CHECK (Capacity::TENDNEXT == lctrl.markIncomingCapacity (next, t3 ));
CHECK (Capacity::SPINTIME == lctrl.markIncomingCapacity (next, t4 ));
CHECK (Capacity::DISPATCH == lctrl.markIncomingCapacity (next,next));
CHECK (Capacity::DISPATCH == lctrl.markIncomingCapacity (next, t5 ));
// while being used rather generously on outgoing capacity
CHECK (Capacity::TENDNEXT == lctrl.markOutgoingCapacity (next, ut ));
CHECK (Capacity::TENDNEXT == lctrl.markOutgoingCapacity (next, t1 ));
CHECK (Capacity::TENDNEXT == lctrl.markOutgoingCapacity (next, t2 ));
CHECK (Capacity::TENDNEXT == lctrl.markOutgoingCapacity (next, t3 ));
CHECK (Capacity::SPINTIME == lctrl.markOutgoingCapacity (next, t4 ));
CHECK (Capacity::DISPATCH == lctrl.markOutgoingCapacity (next,next));
CHECK (Capacity::DISPATCH == lctrl.markOutgoingCapacity (next, t5 ));
}
/** @test verify the re-distribution of free capacity by targeted delay
* - the implementation uses the next-tended start time as anchor point
* - capacity classes which should be scheduled right away will actually
* never call this function — yet still a sensible value is returned here
* - capacity targeted at current work will be redistributed behind the
* next-tended time, and within a time span corresponding to the work realm
* - capacity targeted towards more future work will be distributed within
* the horizon defined by the sleep-cycle
* - especially for capacity sent to sleep, this redistribution works
* without being shifted behind the next-tended time, since in that case
* the goal is to produce a random distribution of the »sleeper« callbacks.
* - the offset is indeed randomised, using current time for randomisation
* @see LoadController::scatteredDelayTime()
* @todo WIP 10/23 ✔ define ⟶ ✔ implement
*/
void
scatteredReCheck()
{
auto is_between = [](auto lo, auto hi, auto val)
{
return lo <= val and val < hi;
};
LoadController lctrl;
TimeVar now = RealClock::now();
Offset ten{FSecs(10)};
Time next{now + ten};
lctrl.tendNext(next);
CHECK (Time::ZERO == lctrl.scatteredDelayTime (now, Capacity::DISPATCH) );
CHECK (Time::ZERO == lctrl.scatteredDelayTime (now, Capacity::SPINTIME) );
CHECK ( ten == lctrl.scatteredDelayTime (now, Capacity::TENDNEXT) );
CHECK (is_between ( ten, ten+ WORK_HORIZON, lctrl.scatteredDelayTime (now, Capacity::NEARTIME)));
CHECK (is_between ( ten, ten+SLEEP_HORIZON, lctrl.scatteredDelayTime (now, Capacity::WORKTIME)));
CHECK (is_between ( ten, ten+SLEEP_HORIZON, lctrl.scatteredDelayTime (now, Capacity::IDLEWAIT)));
lctrl.tendNext(Time::ANYTIME); // reset to ensure we get no base offset
// Offset is randomised based on the current time
// Verify this yields an even distribution
double avg{0};
const size_t REPETITIONS = 1e6;
for (size_t i=0; i< REPETITIONS; ++i)
avg += _raw(lctrl.scatteredDelayTime (RealClock::now(), Capacity::IDLEWAIT));
avg /= REPETITIONS;
auto expect = _raw(SLEEP_HORIZON)/2;
auto error = fabs(avg/expect - 1);
CHECK (0.002 > error); // observing a quite stable skew ~ 0.8‰ on my system
} // let's see if this error bound triggers eventually...
/** @test TODO
* @todo WIP 10/23 🔁 define ⟶ implement
*/
void
walkingDeadline()
{
UNIMPLEMENTED ("walking Deadline");
}
};
/** Register this test class... */
LAUNCHER (SchedulerLoadControl_test, "unit engine");
}}} // namespace vault::gear::test