Displaying 4 results from an estimated 4 matches for "reducelatency".
2013 Jan 11
1
[LLVMdev] Arguments to setLatencyPolicy calls swapped by accident in ConvergingScheduler::checkResourceLimits?
Hi,
In ConvergingScheduler::checkResourceLimits on line 1535 of
MachineScheduler.cpp setLatencyPolicy is called as follows:
// Set ReduceLatency to true if needed.
Bot.setLatencyPolicy(TopCand.Policy);
Top.setLatencyPolicy(BotCand.Policy);
So the Bot scheduling boundary is used to set the latency policy of the
Top candidate and the other way around.
I think this should be:
// Set ReduceLatency to true if needed.
Bot.setLaten...
2016 Oct 28
2
mischeduler
...e aggressively for latency in PostRA mode. We don't check for
// acyclic latency during PostRA, and highly out-of-order processors will
// skip PostRA scheduling.
if (!OtherResLimited) {
if (IsPostRA || (RemLatency + CurrZone.getCurrCycle() >
Rem.CriticalPath)) {
Policy.ReduceLatency |= true;
Why !OtherResLimited? tryCandidate() has already checked for resource
balancing just
before this. To not do the latency check then only means falling back to
original
order.
/Jonas
2019 Sep 09
2
Fwd: MachineScheduler not scheduling for latency
...39;t have enough freedom to move
instructions around once physical registers have been assigned, so I
contend that MachineScheduler needs to consider latency.
I've looked at what's going on in the debugger and the problem seems
to be that GenericSchedulerBase::setPolicy does not set
Policy.ReduceLatency because it thinks that the other zone (Top in
this case) is issue limited. There are lots of things I don't
understand here:
1. "Issue limited" seems to mean that the number of instructions is
greater than the length of the critical path. I don't really
understand why this is an...
2019 Sep 10
2
MachineScheduler not scheduling for latency
...<< OtherCritCount /
SchedModel->getMicroOpFactor() << '\n');
+ }
for (unsigned PIdx = 1, PEnd = SchedModel->getNumProcResourceKinds();
PIdx != PEnd; ++PIdx) {
unsigned OtherCount = getResourceCount(PIdx) + Rem->RemainingCounts[PIdx];
As for "shouldReduceLatency should not be relevant at
MicroOpBufferSize = 1": are you suggesting that shouldReduceLatency
should effectively be changed to always return true on in-order CPUs?
Even with that change, latency comes pretty far down the list of
criteria tested in GenericScheduler::tryCandidate.
Thanks,
Jay....