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author | Andreas Hansson <andreas.hansson@arm.com> | 2012-08-28 14:30:31 -0400 |
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committer | Andreas Hansson <andreas.hansson@arm.com> | 2012-08-28 14:30:31 -0400 |
commit | d53d04473e0d6ca1765f1117072eec59187a7f7b (patch) | |
tree | d336db3bfb308b14ec5bba88e8f4ddee1dde8899 /src/cpu/o3/cpu.hh | |
parent | d14e5857c7e1ee053fb4eb448c4776d7c985c5b2 (diff) | |
download | gem5-d53d04473e0d6ca1765f1117072eec59187a7f7b.tar.xz |
Clock: Rework clocks to avoid tick-to-cycle transformations
This patch introduces the notion of a clock update function that aims
to avoid costly divisions when turning the current tick into a
cycle. Each clocked object advances a private (hidden) cycle member
and a tick member and uses these to implement functions for getting
the tick of the next cycle, or the tick of a cycle some time in the
future.
In the different modules using the clocks, changes are made to avoid
counting in ticks only to later translate to cycles. There are a few
oddities in how the O3 and inorder CPU count idle cycles, as seen by a
few locations where a cycle is subtracted in the calculation. This is
done such that the regression does not change any stats, but should be
revisited in a future patch.
Another, much needed, change that is not done as part of this patch is
to introduce a new typedef uint64_t Cycle to be able to at least hint
at the unit of the variables counting Ticks vs Cycles. This will be
done as a follow-up patch.
As an additional follow up, the thread context still uses ticks for
the book keeping of last activate and last suspend and this should
probably also be changed into cycles as well.
Diffstat (limited to 'src/cpu/o3/cpu.hh')
-rw-r--r-- | src/cpu/o3/cpu.hh | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/src/cpu/o3/cpu.hh b/src/cpu/o3/cpu.hh index b1fd12a2e..5910f314d 100644 --- a/src/cpu/o3/cpu.hh +++ b/src/cpu/o3/cpu.hh @@ -214,9 +214,9 @@ class FullO3CPU : public BaseO3CPU void scheduleTickEvent(int delay) { if (tickEvent.squashed()) - reschedule(tickEvent, nextCycle(curTick() + ticks(delay))); + reschedule(tickEvent, clockEdge(delay)); else if (!tickEvent.scheduled()) - schedule(tickEvent, nextCycle(curTick() + ticks(delay))); + schedule(tickEvent, clockEdge(delay)); } /** Unschedule tick event, regardless of its current state. */ @@ -256,9 +256,9 @@ class FullO3CPU : public BaseO3CPU // Schedule thread to activate, regardless of its current state. if (activateThreadEvent[tid].squashed()) reschedule(activateThreadEvent[tid], - nextCycle(curTick() + ticks(delay))); + clockEdge(delay)); else if (!activateThreadEvent[tid].scheduled()) { - Tick when = nextCycle(curTick() + ticks(delay)); + Tick when = clockEdge(delay); // Check if the deallocateEvent is also scheduled, and make // sure they do not happen at same time causing a sleep that @@ -319,10 +319,10 @@ class FullO3CPU : public BaseO3CPU // Schedule thread to activate, regardless of its current state. if (deallocateContextEvent[tid].squashed()) reschedule(deallocateContextEvent[tid], - nextCycle(curTick() + ticks(delay))); + clockEdge(delay)); else if (!deallocateContextEvent[tid].scheduled()) schedule(deallocateContextEvent[tid], - nextCycle(curTick() + ticks(delay))); + clockEdge(delay)); } /** Unschedule thread deallocation in CPU */ |