Project 11: Influence of the Number of Processors on the Miss Rate
Prepared By:
Suhaimi bin Mohd Sukor
M031010040
Project 11
Configure a system with the following architectural characteristics: • Cache coherence protocol = MESI. • Scheme for bus arbitration = LRU. • Word wide (bits) = 16. • Words by block = 32 (block size = 64 bytes). • Blocks in main memory = 524288 (main memory size = 32 MB). • Blocks in cache = 256 (cache size = 16 KB). • Mapping = Set-Associative. • Cache sets = 64 (four-way set associative caches). • Replacement policy = LRU.
Question :
Does the global miss rate increase or decrease as the number of processors increases? Why? Does this increment or decrement happen for all the benchmarks or does it depend on the
different locality grades, shared data,...? What does it happen with the capacity and coherence misses when you enlarge the number of processors? Are there conflict misses
in these experiments? Why?
Answer
The global miss rate will increase as the number of processor increases. By the result, the increment are happened in all benchmarks. Generally, the greater number of processors,
the higher miss rate and network traffics.
Question:
Configure the number of processors in the SMP using the following configurations: 1, 2, 4, and 8. For each of the configurations, obtain the global miss rate for the system using the three traces that were generated by the post-mortem scheme: FFT, Simple and Weather. (Note:
To change with Comp, Hydro and Nasa7 with your permission)
Answer :
I have attached the result by configuring each of the processor using SMP Cache simulator. I have chose Comp, Hydro and Nasa7 traces to get my result.
Full Result
NO. OF PROCESSOR
MISS RATE (%)
COMP HYDRO NASA7
MISSES NO. MISSES NO. MISSES NO.
1 9.3899 237 8.9798 191 9.3261 173
2 17.631 445 19.464 414 19.892 369
4 18.502 467 21.439 456 22.049 409
8 12.559 317 22.990 489 22.049 409
Number of Processors vs Miss Rate
17.631
19.464
22.9922.049
9.3899
18.502
12.559
8.9798
21.439
9.3261
19.892
22.049
0
5
10
15
20
25
1 2 4 8
No. of Processors
Mis
s R
ate
s (
%)
Comp Hydro Nasa7
Result by using Comp traces
Using Comp tracesNo of Processor : 1
Using Comp tracesNo of Processor : 2
Using Comp tracesNo of Processor : 4
Using Comp tracesNo of Processor : 8
Using Hydro traces
Using Hydro tracesNo of Processor : 1
Using Hydro tracesNo of Processor : 2
Using Hydro tracesNo of Processor : 4
Using Hydro tracesNo of Processor : 8
Using Nasa7 traces
Using Nasa7 tracesNo of Processor : 1
Using Nasa7 tracesNo of Processor : 2
Using Nasa7 tracesNo of Processor : 4
Using Nasa7 tracesNo of Processor : 8
Conclusion
Question:
In conclusion, does the increase of the number of processors improve the multiprocessor system performance? Why and in what sense?
Answer:
In conclusion, the increase of the number of processors can improve the multiprocessor system performance. However, it depends on the bus bandwidth, if the Multiprocessor System have enough bus bandwidth then the performance will increase, if not the system will slow down.