Self Doubt

Question

We have WAR dependency amongst instructions but hazard is when something creates a stall in the pipeline. Can WAR or WAW dependency ever create a stall in the pipeline?. If yes, can someone please quote an example.

Comments

Thanks nitish. So in pipeline where every instruction passes through every stage we won’t have WAR and WAW hazard,right?

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yes and also if reordering is not allowed..

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We generally have RAW hazard in pipeline ( i.e. out(I₁) -  in(I₂)) but to reduce it we go for reordering( because if one instruction creates stall all other instruction following it suffers from it , so better idea is to run independent instruction out of order), which creates two more hazards i.e. WAR and WAW.

Hazard possible out of order also, but dependency cannot. 

Dependency when creating stall becomes Hazard.