A method comprising: configuring a first group of one or more processor cores in a device (100; 602) to run at a first frequency range, the first group of one or more processor cores being associated with a first importance level of multiple different importance levels; configuring a second group of one or more processor cores in the device (100; 602) to run at a second frequency range, wherein frequencies in the second frequency range are lower than frequencies in the first frequency range, the second group of one or more processor cores being associated with a second importance level of the multiple different importance levels; wherein the second importance level has a lower importance than the first importance level; determining an importance level of a first thread scheduled to be executed on the device (100; 602), the importance level being one of the first importance level or the second importance level; determining, based on the importance level of the first thread, whether the first thread is to be executed on the first group of one or more processor cores or the second group of one or more processor cores; and scheduling the first thread for execution on the determined group of one or more processor cores; the method further comprising dynamically adjusting, during operation of the device (100; 602), which processor cores of the device (100; 602) are included in the first group of one or more processor cores and which processor cores of the device (100; 602) are included in the second group of one or more processor cores, the dynamically adjusting comprising: determining whether at least a first threshold number of threads having the first importance level are scheduled on the second group of one or more processor cores, and upgrading at least one processor core in the second group of one or more processor cores to being one of the first group of one or more processor cores in response to at least the first threshold number of threads having the first importance level being scheduled on the second group of one or more processor cores; and/or determining whether at least a second threshold number of threads having the second importance level are scheduled on the first group of one or more processor cores, and downgrading at least one processor core in the first group of one or more processor cores to being one of the second group of one or more processor cores in response to at least the second threshold number of threads having the second importance level being scheduled on the first group of one or more processor cores. configuring a first group of one or more processor cores in a device (100; 602) to run at a first frequency range, the first group of one or more processor cores being associated with a first importance level of multiple different importance levels; configuring a second group of one or more processor cores in the device (100; 602) to run at a second frequency range, wherein frequencies in the second frequency range are lower than frequencies in the first frequency range, the second group of one or more processor cores being associated with a second importance level of the multiple different importance levels; wherein the second importance level has a lower importance than the first importance level; determining an importance level of a first thread scheduled to be executed on the device (100; 602), the importance level being one of the first importance level or the second importance level; determining, based on the importance level of the first thread, whether the first thread is to be executed on the first group of one or more processor cores or the second group of one or more processor cores; and scheduling the first thread for execution on the determined group of one or more processor cores; the method further comprising dynamically adjusting, during operation of the device (100; 602), which processor cores of the device (100; 602) are included in the first group of one or more processor cores and which processor cores of the device (100; 602) are included in the second group of one or more processor cores, the dynamically adjusting comprising: determining whether at least a first threshold number of threads having the first importance level are scheduled on the second group of one or more processor cores, and upgrading at least one processor core in the second group of one or more processor cores to being one of the first group of one or more processor cores in response to at least the first threshold number of threads having the first importance level being scheduled on the second group of one or more processor cores; and/or determining whether at least a first threshold number of threads having the first importance level are scheduled on the second group of one or more processor cores, and upgrading at least one processor core in the second group of one or more processor cores to being one of the first group of one or more processor cores in response to at least the first threshold number of threads having the first importance level being scheduled on the second group of one or more processor cores; and/or determining whether at least a second threshold number of threads having the second importance level are scheduled on the first group of one or more processor cores, and downgrading at least one processor core in the first group of one or more processor cores to being one of the second group of one or more processor cores in response to at least the second threshold number of threads having the second importance level being scheduled on the first group of one or more processor cores.