Both Augustine and Calvin are quite clear that God knew perfectly well beforehand that the creatures He was about to create would sin. Where they differ somewhat is in their explanation
of why and how this was so. In brief, while Augustine follows a line suggesting that God permitted evil, Calvin more boldly declares that He willed it. Both, on the other hand, appeal to the same Felix Culpa (O Fortunate Crime...) justification for this view, namely that a world that included fallen-and-redeemed creatures is better than a world that includes only innocent creatures. However, both vitiate this justification by claiming that the redeemed constitute the minority and that the majority are predestined for something much nastier - and that before ever they were created!
Quotations and references below all come from John Hick's Evil And The God Of Love (MacMillan 1966)
God judged it better to bring good out of evil, than to suffer no evil to exist. Again, For God would never have created any... [men] whose future wickedness He foreknew, unless He had equally known to what uses in behalf of the good He could turn them ....
Later, on page 110, Hick quotes Charles Journet (following the Augustinian approach):
God permits, indeed, that evils come about so as to draw a greater good from them ... and The original fall was permitted only with a view to the Redemption of the world by Christ's sufferings ... Indeed, Journet even adopts the statement of St Francis de Sales that the redeemed state is worth a hundred times more than that of innocence.
On page 112 Hick writes:
Could God, had he wished, have exerted the irresistible influence of His grace within men's souls in such a way as to bring all mankind freely to salvation? Journet continues: Could he always act thus? To ask this of him would be to expect from him a different world from the one he chose to make... Is the divine goodness, having showered its creatures with such help that, should they reject it, the fault should belong entirely to them ... bound, under pain of ceasing to be infinite, to break down the resistance of one who freely wills to rebel against it? Not this question, but another is the one we find unanswerable: why does God sometimes do what he is in no way bound to do? And why does he do it for one person rather than for another? This is where we should listen to St Augustine: Do not judge, if you do not want to err.
Calvin is more forthright than Augustine. On page 120 Hick quotes Calvin as follows:
And it ought not to seem absurd for me to say that God not only foresaw the fall of the first man, and in him the ruin of his descendants, but also meted it out in accordance with his own decision.
Calvin supposes an objector to ask, Why from the beginning did God predestine some to death who, since they did not yet exist, could not yet have deserved the judgement of death? And his answer is that, although predestined to it, men sin freely, and are therefore all personally guilty and rightly condemned.