CWYAlpha

Just another WordPress.com site

Thought this was cool: Latency numbers every programmer should know — Gist

leave a comment »


Comments: “Latency numbers every programmer should know — Gist”

URL: https://gist.github.com/2841832

L1 cache reference 0.5 ns

Branch mispredict 5 ns

L2 cache reference 7 ns 14x L1 cache

Mutex lock/unlock 25 ns

Main memory reference 100 ns 20x L2 cache, 200x L1 cache

Compress 1K bytes with Zippy 3,000 ns

Send 1K bytes over 1 Gbps network 10,000 ns 0.01 ms

SSD random read 150,000 ns

Read 1 MB sequentially from memory 250,000 ns 0.25 ms

Round trip within same datacenter 500,000 ns 0.5 ms

Read 1 MB sequentially from SSD 1,000,000 ns 1 ms 4X memory

Disk seek 10,000,000 ns 10 ms 20x datacenter roundtrip

Read 1 MB sequentially from disk 20,000,000 ns 20 ms 80x memory, 20X SSD

Send packet CA->Netherlands->CA 150,000,000 ns 150 ms

1 ns = 10-9 seconds

1 ms = 10-3 seconds

Assuming ~1GB/sec SSD

By Jeff Dean (http://research.google.com/people/jeff/)

Originally by Peter Norvig (http://norvig.com/21-days.html#answers)

Some updates from: https://gist.github.com/2843375

Great ‘humanized’ comparison version: https://gist.github.com/2843375


from Hacker News 200: https://gist.github.com/2841832?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+hacker-news-feed-200+%28Hacker+News+200%29

Written by cwyalpha

七月 2, 2012 在 11:53 上午

发表在 Uncategorized

发表评论

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / 更改 )

Twitter picture

You are commenting using your Twitter account. Log Out / 更改 )

Facebook photo

You are commenting using your Facebook account. Log Out / 更改 )

Google+ photo

You are commenting using your Google+ account. Log Out / 更改 )

Connecting to %s

%d 博主赞过: