1. A method, comprising: identifying, at a northbridge, a number of memory access requests received at the northbridge from a first processor core of a processor comprising a plurality of processor cores; and independent of a first set of tokens assigned to other processor cores of the plurality of processor cores, dynamically issuing tokens from the northbridge to the first processor core in response to the number of memory access requests received at the northbridge from the first processor core exceeding a threshold, the tokens limiting a maximum number of memory access requests that the first processor core can have pending at the northbridge, wherein dynamically issuing the tokens comprises issuing a first number of tokens by: issuing a minimum number of tokens to the first processor core, the minimum number of tokens independent of the numbers of memory access requests generated by the processor core; and issuing a second number of tokens in response to the number of memory access requests received at the northbridge exceeding the threshold, the first number of tokens including the minimum number of tokens and the second number of tokens, wherein issuing the second number of tokens comprises issuing the second number of tokens in response to the number of memory access requests received at the northbridge exceeding the threshold in not more than a specified amount of time.