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Total RPS calculation looks wrong as sum of CPU requests and Memory Requests

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#1

A service receives both the CPU-bound and memory-bound requests. Considering the case that half the requests are CPU-bound and the other half memory-bound, we can handle a total of
360/2 + 16000/2 =8,180≈ 8,000 RPS

Please explain this.
I think this is wrong since if a server can handle 8080 requests per second , and we are assuming 50% requests to be from CPU. Then the server should handle 4040 CPU requests. But in calculation we already cleared that CPU can handle only 360 RPS

Course: Grokking Modern System Design Interview for Engineers & Managers - Learn Interactively
Lesson: Put Back-of-the-envelope Numbers in Perspective - Grokking Modern System Design Interview for Engineers & Managers

2 Likes
#2

+1to the question, the logic seems weird to me.

#3

+1 to this question. It seems like the Server should be only able to handle 720 RPS (if half are CPU bound and half are memory bound)

#4

Hi Tushar, Zihao, and micro

We have revamped the “Back-of-the-envelope calculations” throughout the course. Please give it a read for a better understanding of the topic.

Thank you & regards,