System Design

Question 1

CPU Registers Access Time

Answer 1

0.5 nanoseconds

Question 2

L1 cache access

Answer 2

0.9 nanoseconds

Question 3

L2 cache access

Answer 3

2.8 nanoseconds

Question 4

L3 cache access

Answer 4

12.9 nano seconds

Question 5

Reading 1 MB from Memory

Answer 5

9 micro seconds

Question 6

SSD Write Latency

Answer 6

100-1000 microseconds

Round trip in the same data center takes around 500 microseconds

Question 7

Read 1MB sequentially from disk

Answer 7

2 ms

Question 8

Disk seek time

Answer 8

4 ms

Question 9

Intrazone network latency

Answer 9

5 ms

Question 10

Network round trip between two zones (inter-zone) - including reading 1GB of sequential data from memory on the same server

Answer 10

1ms - 100ms

Question 11

Password Hashing Algo

Answer 11

100ms - 1000ms

Question 12

Response Time Equation

Answer 12

Time (latency) + Time (processing)

Question 13

Effective API Average Response Time

Answer 13

0.1 - 1 second

Question 14

Seconds to MicroSeconds

Answer 14

1 / 1000000 (µs)

Question 15

Seconds to Milliseconds

Answer 15

1 / 1000 (ms)

Question 16

Seconds to NanoSeconds

Answer 16

1 / 1000000000 (ns)

Question 17

DNS Lookup

Answer 17

time to resolve the IP address against a domain name through a DNS server

Question 18

TCP Handshake

Answer 18

time to establish an initial connection between the client and the server

Question 19

SSL/TLS handshake

Answer 19

time to create a secure communication channel for data exchange

Question 20

Transfer start

Answer 20

time to acquire the first byte of the requested data in the response message. Includes both RTT get/post (round trip time of get/post) messages and processing time at the server end

Question 21

Transfer start formula

Answer 21

RTT get/post + Time (processing)

Question 22

Download

Answer 22

Time taken by a client to fetch the complete data

Question 23

Base Time

Answer 23

Generally includes DNS lookup, TCP handshake and SSL/TLS handshake

Question 24

Latency

Answer 24

Base Time + RTT get/post + download time

Question 25

CPU Bound RPS formula

Answer 25

NumCPU / Task Time

Question 26

Memory Bound RPS formula

Answer 26

(RAM / Worker Memory) / Task Time

Question 27

GET / POST Base Time

Answer 27

Min - 120.5
Max - 201.5

Question 28

RTT GET

Answer 28

70ms

Question 29

RTT POST

Answer 29

260ms + (1.15 * size of request)

Question 30

Download Time GET

Answer 30

0.4 * size of response (ms)

Question 31

Download Time POST

Answer 31

1.7ms

Question 32

GET / POST Processing Time

Answer 32

Min - 4 ms
Max - variable

Question 33

Average size of an image

Answer 33

200KB