

Google's Numbers Every Developer Should Know - thedob
http://surana.wordpress.com/2009/01/01/numbers-everyone-should-know/

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blurry
Please don't post a link to your own blog when all it does is link to another
post. Just link to the original.

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pg
Anyone know where the original is?

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suranap
That's my blog, but I didn't post it here. The original link is in the post:
[http://moderator.appspot.com/#15/e=c9&t=10c](http://moderator.appspot.com/#15/e=c9&t=10c)

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azanar
He may have meant this when he created the slide, but precise numbers here
seem less important than relative magnitude as long as one is reasonably
close.

One could be a few ns off on how long a L2 cache lookup takes, and endure in
all but the most time-critical situations. Far bigger problems occur when one
failed to account for drive seeks being around eight orders of magnitude
slower than L2 cache lookups.

It doesn't strike me as a list of numbers to memorize and be able to recite,
but more the sake of cultivating an intuition of where to start looking for
places to optimize communication, and the relative order of things one should
focus on.

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Tichy
"# Read 1 MB sequentially from network 10,000,000 ns # Read 1 MB sequentially
from disk 30,000,000 ns"

That seems weird - wouldn't the 1MB be read from a disk at the other end of
the network? So how can disk be slower than network (unless the network is all
RAM-Disk...).

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lacker
It doesn't have to be read from disk at the other end. It could be data that's
already cached in memory, you just have to talk to the cache server over the
network.

