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scheduler: Cache quantum length

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This commit is contained in:
Pawel Dziepak 2014-01-17 01:43:41 +01:00
parent 4835c216f7
commit 3dce49af0e
2 changed files with 21 additions and 18 deletions
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36
src/system/kernel/scheduler/scheduler_thread.cpp
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@ -11,6 +11,9 @@ using namespace Scheduler;
static bigtime_t sQuantumLengths[THREAD_MAX_SET_PRIORITY + 1];
const int32 kMaximumQuantumLengthsCount = 20;
static bigtime_t sMaximumQuantumLengths[kMaximumQuantumLengthsCount];
void
ThreadData::_InitBase()
@ -18,6 +21,7 @@ ThreadData::_InitBase()
fPriorityPenalty = 0;
fAdditionalPenalty = 0;
fEffectivePriority = GetPriority();
fBaseQuantum = sQuantumLengths[GetEffectivePriority()];
fCPUBound = false;
fTimeUsed = 0;
@ -83,15 +87,6 @@ ThreadData::_ChooseCPU(CoreEntry* core, bool& rescheduleNeeded) const
}
inline bigtime_t
ThreadData::_GetBaseQuantum() const
{
SCHEDULER_ENTER_FUNCTION();
return sQuantumLengths[GetEffectivePriority()];
}
ThreadData::ThreadData(Thread* thread)
:
fThread(thread)
@ -190,19 +185,16 @@ ThreadData::ComputeQuantum() const
{
SCHEDULER_ENTER_FUNCTION();
bigtime_t quantum = _GetBaseQuantum();
if (IsRealTime())
return quantum;
return fBaseQuantum;
int32 threadCount = fCore->ThreadCount();
if (fCore->CPUCount() > 0)
threadCount /= fCore->CPUCount();
if (threadCount >= 1) {
quantum
= std::min(gCurrentMode->maximum_latency / threadCount, quantum);
quantum = std::max(quantum, gCurrentMode->minimal_quantum);
}
bigtime_t quantum = fBaseQuantum;
if (threadCount < kMaximumQuantumLengthsCount)
quantum = std::min(sMaximumQuantumLengths[threadCount], quantum);
return quantum;
}
@ -232,6 +224,16 @@ ThreadData::ComputeQuantumLengths()
sQuantumLengths[priority] = _ScaleQuantum(kQuantum2, kQuantum1,
B_NORMAL_PRIORITY, B_IDLE_PRIORITY, priority);
}
for (int32 threadCount = 0; threadCount < kMaximumQuantumLengthsCount;
threadCount++) {
bigtime_t quantum = gCurrentMode->maximum_latency;
if (threadCount != 0)
quantum /= threadCount;
quantum = std::max(quantum, gCurrentMode->minimal_quantum);
sMaximumQuantumLengths[threadCount] = quantum;
}
}
@ -276,6 +278,8 @@ ThreadData::_ComputeEffectivePriority() const
ASSERT(fEffectivePriority < B_FIRST_REAL_TIME_PRIORITY);
ASSERT(fEffectivePriority >= B_LOWEST_ACTIVE_PRIORITY);
}
fBaseQuantum = sQuantumLengths[GetEffectivePriority()];
}

3
src/system/kernel/scheduler/scheduler_thread.h
View File

@ -29,8 +29,6 @@ private:
inline CPUEntry* _ChooseCPU(CoreEntry* core,
bool& rescheduleNeeded) const;
inline bigtime_t _GetBaseQuantum() const;
public:
ThreadData(Thread* thread);
@ -121,6 +119,7 @@ private:
int32 fAdditionalPenalty;
mutable int32 fEffectivePriority;
mutable bigtime_t fBaseQuantum;
bigtime_t fTimeUsed;