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Replaced ignoreStackAndRegisters with stackSize in GC_step
This commit is contained in:
Ruslan Mustakov
14
doc/gc.txt
14
doc/gc.txt
@@ -56,7 +56,7 @@ file as well). With this switch the GC supports the following operations:
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.. code-block:: nim
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proc GC_setMaxPause*(MaxPauseInUs: int)
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proc GC_step*(us: int, strongAdvice, ignoreStackAndRegisters = false)
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proc GC_step*(us: int, strongAdvice = false, stackSize = -1)
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The unit of the parameters ``MaxPauseInUs`` and ``us`` is microseconds.
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@@ -75,11 +75,13 @@ These two procs are the two modus operandi of the realtime GC:
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This allows the GC to perform some work for up to ``us`` time. This is
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useful to call in a main loop to ensure the GC can do its work. To
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bind all GC activity to a ``GC_step`` call, deactivate the GC with
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``GC_disable`` at program startup. Notice that you may ask GC to not
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scan stack and registers for references via ``ignoreStackAndRegisters``
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parameter. This may reduce the step time depending on the stack depth,
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but use it only when you are sure that neither the stack nor the registers
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contain unique references to objects that must be preserved.
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``GC_disable`` at program startup. If ``strongAdvice`` is set to ``true``,
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GC will be forced to perform collection cycle. Otherwise, GC may decide not
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to do anything, if there is not much garbage to collect.
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You may also specify the current stack size via ``stackSize`` parameter.
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It can improve performance, when you know that there are no unique Nim
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references below certain point on the stack. Make sure the size you specify
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is greater than the potential worst case size.
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These procs provide a "best effort" realtime guarantee; in particular the
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cycle collector is not aware of deadlines yet. Deactivate it to get more
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@@ -905,19 +905,19 @@ proc unmarkStackAndRegisters(gch: var GcHeap) =
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#sysAssert c.typ != nil, "unmarkStackAndRegisters 2"
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gch.decStack.len = 0
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proc collectCTBody(gch: var GcHeap, ignoreStackAndRegisters = false) =
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proc collectCTBody(gch: var GcHeap) =
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when withRealTime:
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let t0 = getticks()
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sysAssert(allocInv(gch.region), "collectCT: begin")
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when not defined(nimCoroutines):
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gch.stat.maxStackSize = max(gch.stat.maxStackSize, stackSize())
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sysAssert(gch.decStack.len == 0, "collectCT")
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prepareForInteriorPointerChecking(gch.region)
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if not ignoreStackAndRegisters:
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when not defined(nimCoroutines):
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gch.stat.maxStackSize = max(gch.stat.maxStackSize, stackSize())
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markStackAndRegisters(gch)
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markThreadStacks(gch)
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gch.stat.maxStackCells = max(gch.stat.maxStackCells, gch.decStack.len)
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inc(gch.stat.stackScans)
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markStackAndRegisters(gch)
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markThreadStacks(gch)
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gch.stat.maxStackCells = max(gch.stat.maxStackCells, gch.decStack.len)
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inc(gch.stat.stackScans)
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if collectZCT(gch):
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when cycleGC:
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if getOccupiedMem(gch.region) >= gch.cycleThreshold or alwaysCycleGC:
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@@ -927,8 +927,7 @@ proc collectCTBody(gch: var GcHeap, ignoreStackAndRegisters = false) =
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gch.cycleThreshold = max(InitialCycleThreshold, getOccupiedMem() *
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CycleIncrease)
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gch.stat.maxThreshold = max(gch.stat.maxThreshold, gch.cycleThreshold)
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if not ignoreStackAndRegisters:
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unmarkStackAndRegisters(gch)
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unmarkStackAndRegisters(gch)
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sysAssert(allocInv(gch.region), "collectCT: end")
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when withRealTime:
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@@ -972,17 +971,28 @@ when withRealTime:
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proc GC_setMaxPause*(MaxPauseInUs: int) =
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gch.maxPause = MaxPauseInUs.toNano
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proc GC_step(gch: var GcHeap, us: int, strongAdvice: bool, ignoreStackAndRegisters: bool) =
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proc GC_step(gch: var GcHeap, us: int, strongAdvice: bool) =
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acquire(gch)
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gch.maxPause = us.toNano
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if (gch.zct.len >= ZctThreshold or (cycleGC and
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getOccupiedMem(gch.region)>=gch.cycleThreshold) or alwaysGC) or
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strongAdvice:
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collectCTBody(gch, ignoreStackAndRegisters)
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collectCTBody(gch)
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release(gch)
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proc GC_step*(us: int, strongAdvice, ignoreStackAndRegisters = false) =
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GC_step(gch, us, strongAdvice, ignoreStackAndRegisters)
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proc GC_step*(us: int, strongAdvice = false, stackSize = -1) {.noinline.} =
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var stackTop {.volatile.}: pointer
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let prevStackBottom = gch.stackBottom
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if stackSize >= 0:
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stackTop = addr(stackTop)
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when stackIncreases:
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gch.stackBottom = cast[pointer](
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cast[ByteAddress](stackTop) - sizeof(pointer) * 6 - stackSize)
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else:
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gch.stackBottom = cast[pointer](
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cast[ByteAddress](stackTop) + sizeof(pointer) * 6 + stackSize)
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GC_step(gch, us, strongAdvice)
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gch.stackBottom = prevStackBottom
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when not defined(useNimRtl):
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proc GC_disable() =
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@@ -894,18 +894,18 @@ proc unmarkStackAndRegisters(gch: var GcHeap) =
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decRef(d[i])
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gch.decStack.len = 0
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proc collectCTBody(gch: var GcHeap, ignoreStackAndRegisters = false) =
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proc collectCTBody(gch: var GcHeap) =
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when withRealTime:
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let t0 = getticks()
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sysAssert(allocInv(gch.region), "collectCT: begin")
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when not defined(nimCoroutines):
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gch.stat.maxStackSize = max(gch.stat.maxStackSize, stackSize())
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sysAssert(gch.decStack.len == 0, "collectCT")
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prepareForInteriorPointerChecking(gch.region)
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if not ignoreStackAndRegisters:
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when not defined(nimCoroutines):
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gch.stat.maxStackSize = max(gch.stat.maxStackSize, stackSize())
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markStackAndRegisters(gch)
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gch.stat.maxStackCells = max(gch.stat.maxStackCells, gch.decStack.len)
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inc(gch.stat.stackScans)
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markStackAndRegisters(gch)
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gch.stat.maxStackCells = max(gch.stat.maxStackCells, gch.decStack.len)
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inc(gch.stat.stackScans)
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if collectZCT(gch):
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when cycleGC:
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if getOccupiedMem(gch.region) >= gch.cycleThreshold or alwaysCycleGC:
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@@ -914,8 +914,7 @@ proc collectCTBody(gch: var GcHeap, ignoreStackAndRegisters = false) =
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gch.cycleThreshold = max(InitialCycleThreshold, getOccupiedMem() *
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CycleIncrease)
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gch.stat.maxThreshold = max(gch.stat.maxThreshold, gch.cycleThreshold)
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if not ignoreStackAndRegisters:
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unmarkStackAndRegisters(gch)
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unmarkStackAndRegisters(gch)
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sysAssert(allocInv(gch.region), "collectCT: end")
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when withRealTime:
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@@ -950,15 +949,26 @@ when withRealTime:
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proc GC_setMaxPause*(MaxPauseInUs: int) =
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gch.maxPause = MaxPauseInUs.toNano
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proc GC_step(gch: var GcHeap, us: int, strongAdvice, ignoreStackAndRegisters: bool) =
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proc GC_step(gch: var GcHeap, us: int, strongAdvice: bool) =
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gch.maxPause = us.toNano
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if (gch.zct.len >= ZctThreshold or (cycleGC and
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getOccupiedMem(gch.region)>=gch.cycleThreshold) or alwaysGC) or
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strongAdvice:
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collectCTBody(gch, ignoreStackAndRegisters)
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collectCTBody(gch)
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proc GC_step*(us: int, strongAdvice, ignoreStackAndRegisters = false) =
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GC_step(gch, us, strongAdvice, ignoreStackAndRegisters)
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proc GC_step*(us: int, strongAdvice = false, stackSize = -1) {.noinline.} =
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var stackTop {.volatile.}: pointer
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let prevStackBottom = gch.stackBottom
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if stackSize >= 0:
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stackTop = addr(stackTop)
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when stackIncreases:
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gch.stackBottom = cast[pointer](
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cast[ByteAddress](stackTop) - sizeof(pointer) * 6 - stackSize)
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else:
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gch.stackBottom = cast[pointer](
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cast[ByteAddress](stackTop) + sizeof(pointer) * 6 + stackSize)
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GC_step(gch, us, strongAdvice)
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gch.stackBottom = prevStackBottom
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when not defined(useNimRtl):
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proc GC_disable() =
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