
Interactive Latency Numbers - agbell
https://colin-scott.github.io/personal_website/research/interactive_latency.html
======
mlyle
This, overall, is questionable. Just what disk seeks in 2 milliseconds? SSDs
are much faster than this; spinning disks still much slower.

Other quantities are unclear what they mean. "Send 2000 bytes over commodity
network"\-- 44ns. but round trip in one data center is 500us. So is 44 ns just
the wire time of 2000 bytes (363 gigabits/second is "commodity"??)-- but other
operations count the actual _edge / completion_ of the operations?

~~~
thedance
This does seem to have parted ways with reality in several respects. Read a
megabyte from main memory in three microseconds? That’s much too fast, because
they model memory getting faster. But they model CPU as stagnant, meaning the
time to compress a 2kb block with zippy (snappy outside google) is much too
slow. CPUs are not stagnant.

ETA: 20 GB/s SSD reads is a bit fanciful, as is > 1 GB/s sequential from a
disk.

~~~
dang
Could you please stop creating accounts for every few comments you post? We
ban accounts that do that. This is in the site guidelines:
[https://news.ycombinator.com/newsguidelines.html](https://news.ycombinator.com/newsguidelines.html).

HN is a community and we want it to remain one. For that, users need some
identity for others to relate to. Otherwise we may as well have no usernames
and no community, and that would be a different kind of forum.
[https://hn.algolia.com/?query=by:dang%20community%20identity...](https://hn.algolia.com/?query=by:dang%20community%20identity&sort=byDate&dateRange=all&type=comment&storyText=false&prefix&page=0)

You needn't use your real name, of course.

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thedance
The problem is your weird anti-abuse hacks automatically shadow-ban whatever
account I have if I load HN from certain IPs. So I can’t use any account
that’s been burned that way. Of course in the past you’ve denied that this
happens, but I can demonstrate it easily.

~~~
dang
Let's try a different way. I've marked your current account legit so as to
exempt it from HN's anti-abuse software. As long as you keep following the
site guidelines, it should be fine to stick with this one from now on. If
you'd rather use a different account, let us know at hn@ycombinator.com.

I'm not sure what past statement you're referring to, but HN's software
doesn't shadowban anybody just for accessing the site from a specific IP, so
whatever you're experiencing, that can't be it. Unless it's a bug we haven't
seen.

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wtallis
As always, many of these quantities are gross approximations, modeled as
continuous improvement instead of step functions, and often missing out on
where performance has permanently plateaued. Looking at the numbers for any
one year is a waste of time. Only the long-term trends are instructive,
particularly where operations trade place in rankings (eg. due to bandwidth
increases with constant latency).

There's also something fishy about the scrolling in the source code box.

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doctor_eval
Even at the gross level, I'm pretty sure that RTT CA <-> Netherlands has
improved in the last 30 years too. e.g. in the early 90's a lot of
international data traffic went via satellite, and packet switching times have
also improved since then.

~~~
mlyle
Yup. In March 1990, the first T1 connection between the US and Europe internet
went online. Not to mention the wire time of a datagram over such slow links
is a long time, even ignoring the delays on individual devices.

Also--- 500us ping in the "same datacenter" for all time? I remember pings on
the same segment being 2-3 milliseconds typical in 1995-- let alone crossing
some routers with 68030's in them.

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_nalply
Probably of dubious use but perhaps to have a comparison also have the time of
some assembler instructions like ADD, MUL and DIV. Just an idea. When I saw:
branch mispredict 3ns, I thought first, okay and how many typical assembler
instruction is this?

