cpu: fix issue with sampling kernels (#1016)

aphrodite/modeling/layers/sampler.py

@@ -17,6 +17,7 @@ from aphrodite.common.sampling_params import SamplingType
 from aphrodite.common.sequence import (CompletionSequenceGroupOutput, Logprob,
                                        PromptLogprobs, SampleLogprobs,
                                        SequenceOutput)
+from aphrodite.common.utils import is_cpu
 from aphrodite.spec_decode.metrics import SpecDecodeWorkerMetrics
 from aphrodite.triton_utils import HAS_TRITON
 
@@ -1464,7 +1465,7 @@ def _sample_with_torch(
 
             seq_groups_arg = (None if sampling_type == SamplingType.RANDOM else
                               seq_groups)
-            if APHRODITE_USE_SAMPLING_KERNELS is not None:
+            if APHRODITE_USE_SAMPLING_KERNELS and not is_cpu():
                 multinomial_samples[
                     sampling_type] = _top_k_top_p_multinomial_with_kernels(
                         probs[long_sample_indices],