v**********6
发帖数: 86 | 1 已经gg,记得的一些题目分享给大家，同时也看看大家有什么解法，自己现在还不是很
确定:) 因为是一个architect的职位，所以不是纯软件的问题，有的可能需要一些
power的背景知识。
1. Suppose we have 2 pipelined hardware multipliers(or some other hardware).
One is working at 1GHz with 2 operations executed in parallel at the same
time. The other one is at 500GHz with 4 operations. Suppose we have
transistors of 3 types(low leaky(30%),middle leaky(50%) and high leaky(70%))
and here leaky means leakage power of the transistor. Which multiplier
should we use considering the 3 types of transistor?
2.In the new mobile phone, we can either choose to use a 1GHz solo core or
500MHz duo core processor. What tradeoffs should we consider?
3. We run two video game benchmarks on our new designed SOC. The two
benchmarks have the same instruction set. The benchmark with higher power
consumption always work well while the other one always get stuck. What can
be the problems?
4.In Linux, we use virtual address.So each process will think it has 4 GB
memory space even if the real memory is only 2GB. Now suppose we do not have
MMU and programmer use real physical address in their program. We only have
small size of physical memory. How can we design the system? | d*********y
发帖数: 81 | | f*********5
发帖数: 1237 | 3
).
))
Can we use different Vt transistors for the two pipelines?
【在 v**********6 的大作中提到】
: 已经gg,记得的一些题目分享给大家，同时也看看大家有什么解法，自己现在还不是很
: 确定:) 因为是一个architect的职位，所以不是纯软件的问题，有的可能需要一些
: power的背景知识。
: 1. Suppose we have 2 pipelined hardware multipliers(or some other hardware).
: One is working at 1GHz with 2 operations executed in parallel at the same
: time. The other one is at 500GHz with 4 operations. Suppose we have
: transistors of 3 types(low leaky(30%),middle leaky(50%) and high leaky(70%))
: and here leaky means leakage power of the transistor. Which multiplier
: should we use considering the 3 types of transistor?
: 2.In the new mobile phone, we can either choose to use a 1GHz solo core or
| c****p
发帖数: 6474 | 4 1. Suppose we have 2 pipelined hardware multipliers(or some other hardware).
One is working at 1GHz with 2 operations executed in parallel at the same
time. The other one is at 500MHz with 4 operations. Suppose we have
transistors of 3 types(low leaky(30%),middle leaky(50%) and high leaky(70%))
and here leaky means leakage power of the transistor. Which multiplier
should we use considering the 3 types of transistor?
P_dynamic = alpha * f（^2？） * V * C
P_static = V * C * 1/f
第一个f是两倍，C是一倍。第二个f低，C大于两倍（f高的流水线可以多级，硬件复用
效率高）。
然后是看P_D和P_S的trade-off
2.In the new mobile phone, we can either choose to use a 1GHz solo core or
500MHz duo core processor. What tradeoffs should we consider?
a.功耗和频率实际上呈平方关系，两倍的频率就是四倍的功耗。
b.应用场景，强调单线程还是多线程，涉及performance
c.芯片面积，和功耗也间接相关
3. We run two video game benchmarks on our new designed SOC. The two
benchmarks have the same instruction set. The benchmark with higher power
consumption always work well while the other one always get stuck. What can
be the problems?
跑高能耗应用的时候温度上升，降频；降频之后切到了低能耗应用，卡顿但是温度降下
来了，升频，结果又切到了高能耗应用。
4.In Linux, we use virtual address.So each process will think it has 4 GB
memory space even if the real memory is only 2GB. Now suppose we do not have
MMU and programmer use real physical address in their program. We only have
small size of physical memory. How can we design the system?
不知道。把程序的PA映射到内存的address上？这不还是个MMU么……
).
))
【在 v**********6 的大作中提到】
: 已经gg,记得的一些题目分享给大家，同时也看看大家有什么解法，自己现在还不是很
: 确定:) 因为是一个architect的职位，所以不是纯软件的问题，有的可能需要一些
: power的背景知识。
: 1. Suppose we have 2 pipelined hardware multipliers(or some other hardware).
: One is working at 1GHz with 2 operations executed in parallel at the same
: time. The other one is at 500GHz with 4 operations. Suppose we have
: transistors of 3 types(low leaky(30%),middle leaky(50%) and high leaky(70%))
: and here leaky means leakage power of the transistor. Which multiplier
: should we use considering the 3 types of transistor?
: 2.In the new mobile phone, we can either choose to use a 1GHz solo core or
| x**1
发帖数: 892 | 5
).
))
请给我解释一下 p leakage你怎么得到 vc/f的
http://blaauw.eecs.umich.edu/getFile.php?id=38&sid=nnxdqhqhnosz
还有 p dynamic = alpha c v^2 f
【在 c****p 的大作中提到】
: 1. Suppose we have 2 pipelined hardware multipliers(or some other hardware).
: One is working at 1GHz with 2 operations executed in parallel at the same
: time. The other one is at 500MHz with 4 operations. Suppose we have
: transistors of 3 types(low leaky(30%),middle leaky(50%) and high leaky(70%))
: and here leaky means leakage power of the transistor. Which multiplier
: should we use considering the 3 types of transistor?
: P_dynamic = alpha * f（^2？） * V * C
: P_static = V * C * 1/f
: 第一个f是两倍，C是一倍。第二个f低，C大于两倍（f高的流水线可以多级，硬件复用
: 效率高）。
| v**********6
发帖数: 86 | 6
).
))
第一个题，根据我知道的，leakage是和电压工艺成正比，和频率关系好像不大。我也
知道是这样一个tradeoff,但是接下去就不知道怎么分析了，感觉满难的,不知道这个
pipeline关键字能不能起到什么作用。。。。
第三题，我没说清楚，这两个benchmakr是在不同的时候跑的，而且可以想成在同样的
电压和频率下跑的
【在 c****p 的大作中提到】
: 1. Suppose we have 2 pipelined hardware multipliers(or some other hardware).
: One is working at 1GHz with 2 operations executed in parallel at the same
: time. The other one is at 500MHz with 4 operations. Suppose we have
: transistors of 3 types(low leaky(30%),middle leaky(50%) and high leaky(70%))
: and here leaky means leakage power of the transistor. Which multiplier
: should we use considering the 3 types of transistor?
: P_dynamic = alpha * f（^2？） * V * C
: P_static = V * C * 1/f
: 第一个f是两倍，C是一倍。第二个f低，C大于两倍（f高的流水线可以多级，硬件复用
: 效率高）。
|
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