BreakingPoint< CONF > Class Template Reference

#include "/Werk/devel/lumi/tests/vault/gear/stress-test-rig.hpp"

Description

template<class CONF>
class vault::gear::test::bench::BreakingPoint< CONF >

Specific stress test scheme to determine the »breaking point« where the Scheduler starts to slip.

Definition at line 276 of file stress-test-rig.hpp.

Public Member Functions
auto	perform ()
	Launch a measurement sequence to determine the »breaking point« for the configured test load and parametrisation of the Scheduler. More...

Classes
struct	Res

Private Types
using	TestLoad = typename CONF::TestLoad
using	TestSetup = typename TestLoad::ScheduleCtx

Private Member Functions
template<class FUN >
Res	conductBinarySearch (FUN &&runTestCase, vector< Res > const &results)
	invoke a binary search to produce a sequence of test series with the goal to narrow down the stressFact where the Schedule slips away.
void	configureTest (TestSetup &testSetup, double stressFac)
	prepare the ScheduleCtx for a specifically parametrised test series
bool	decideBreakPoint (Res &res)
	criterion to decide if this test series constitutes a slipped schedule
void	maybeAdaptScaleEmpirically (TestSetup &testSetup, double stressFac)
	Attempt to factor out some observable properties, which are considered circumstantial and not a direct result of scheduling overheads. More...
Res	runProbes (TestSetup &testSetup, double stressFac)
	perform a repetition of test runs and compute statistics
void	showRef (TestSetup &testSetup)
void	showRes (Res &res)
void	showRun (uint i, double delta, double t, bool over, bool fail)
void	showStep (Res &res)

Private Attributes
double	adjustmentFac {1.0}
	adaptive scale correction based on observed behaviour
_Fmt	fmtResSDv_ {"%9s= %5.2f ±%4.2f%s"}
_Fmt	fmtResVal_ {"%9s: %5.2f%s"}
_Fmt	fmtRun_ {"....·%-2d: Δ=%4.1f t=%4.1f %s %s"}
_Fmt	fmtStep_ { "%4.2f| : ∅Δ=%4.1f±%-4.2f ∅t=%4.1f %s %%%-3.0f -- expect:%4.1fms"}
size_t	gaugeProbes = 3 * CONF::REPETITIONS

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Class Documentation

vault::gear::test::bench::BreakingPoint::Res

struct vault::gear::test::bench::BreakingPoint::Res

Class Members
double	stressFac
double	percentOff
double	stdDev
double	avgDelta
double	avgTime
double	expTime

Collaboration diagram for BreakingPoint< CONF >::Res:

Member Function Documentation

maybeAdaptScaleEmpirically()

void maybeAdaptScaleEmpirically ( TestSetup &  testSetup, double  stressFac  )

inlineprivate

Attempt to factor out some observable properties, which are considered circumstantial and not a direct result of scheduling overheads.

The artificial computational load is known to drift towards larger values than calibrated; moreover the actual concurrency achieved can deviate from the heuristic assumptions built into the testing schedule. The latter is problematic to some degree however, since the Scheduler is bound to scale down capacity when idle. To strike a reasonable balance, this adjustment of the measurement scale is done only initially, and when the stress factor is high and some degree of pressure on the scheduler can thus be assumed.

Definition at line 393 of file stress-test-rig.hpp.

References StressTestRig< maxFan >::showRef, StressTestRig< maxFan >::showRes, StressTestRig< maxFan >::showStep, and StressTestRig< maxFan >::testSetup().

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perform()

auto perform ( )

inline

Launch a measurement sequence to determine the »breaking point« for the configured test load and parametrisation of the Scheduler.

Returns

a tuple [stress-factor, ∅delta, ∅run-time]

Definition at line 459 of file stress-test-rig.hpp.

References Config::COMPUTATION_CAPACITY, StressTestRig< maxFan >::showRef, StressTestRig< maxFan >::showRes, StressTestRig< maxFan >::testLoad(), and TRANSIENTLY.

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Inheritance diagram for BreakingPoint< CONF >:

Collaboration diagram for BreakingPoint< CONF >:

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The documentation for this class was generated from the following file:

• stress-test-rig.hpp