| 3. |
- Goel, Bhavishya, 1981, et al.
(författare)
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Infrastructures for Measuring Power
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Energy-aware resource management requires some means of measuring power consumption. We present three approaches to measuring processor power. The easiest, least intrusive places a power meter between the system and power outlet. Unfortunately, this provides a single system measurement, and acuity is limited by device sampling frequency. Another method samples power at PSU voltage outputs using current transducers. This logs consumption separately per component, but requires custom hardware and an expensive analog acquisition device. A more accurate alternative samples power directly at the processor voltage regulator’s current-sensing pin, but requires motherboard intrusion. We explain implementation of each approach step-by-step.
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| 4. |
- Kaxiras, Stefanos, et al.
(författare)
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Efficient, snoopless, System-on-Chip coherence
- 2012
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Ingår i: SOC Conference (SOCC), 2012 IEEE International. - 9781467312950 ; , s. 230-235
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Konferensbidrag (refereegranskat)abstract
- Coherence in a System-on-Chip (SoC) introduces complexity and overhead (snooping caches/directory, state bits, invalidations, etc.) in exchange for a clean and uniform shared memory model. As it is typical today, a SoC comprises a variety of cores with local caches, accelerators with local memories, and some form of shared last-level cache (LLC), all interconnected with shared buses. We propose a very simple coherence protocol, fit for this environment, that eliminates L1 snooping and its associated complexity and costs (power). In essence, we remove all coherence decisions from local caches by simply determining at the LLC whether data are private or shared. This makes a write-through policy a practical and effective alternative to maintain coherence. In the local caches, we dynamically select between writeback for private data, or write-through for shared data. Self-invalidation of the shared data on synchronization points eliminates the need to snoop, with just a data-race-free guarantee from software. Our evaluation shows that this simple protocol outperforms a traditional snooping protocol while at the same time significantly reducing L1, shared cache, and bus energy consumption.
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